U.S. patent application number 16/755806 was filed with the patent office on 2020-10-15 for ink compositions with high quantum dot concentrations for display devices.
The applicant listed for this patent is KATEEVA, INC.. Invention is credited to Christopher D. Favaro, William P. Freeman, Florian Pschenitzka, Teresa A. Ramos, Elena Rogojina.
Application Number | 20200326597 16/755806 |
Document ID | / |
Family ID | 1000004972309 |
Filed Date | 2020-10-15 |
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United States Patent
Application |
20200326597 |
Kind Code |
A1 |
Rogojina; Elena ; et
al. |
October 15, 2020 |
INK COMPOSITIONS WITH HIGH QUANTUM DOT CONCENTRATIONS FOR DISPLAY
DEVICES
Abstract
Organic ligand-capped quantum dots and curable ink compositions
containing the organic ligand-capped quantum dots are provided.
Also provided are thin films formed from the ink compositions.
Inventors: |
Rogojina; Elena; (Newark,
CA) ; Freeman; William P.; (Newark, CA) ;
Favaro; Christopher D.; (Newark, CA) ; Pschenitzka;
Florian; (Newark, CA) ; Ramos; Teresa A.;
(Newark, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KATEEVA, INC. |
Newark |
CA |
US |
|
|
Family ID: |
1000004972309 |
Appl. No.: |
16/755806 |
Filed: |
October 3, 2018 |
PCT Filed: |
October 3, 2018 |
PCT NO: |
PCT/US18/54214 |
371 Date: |
April 13, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62573539 |
Oct 17, 2017 |
|
|
|
62634506 |
Feb 23, 2018 |
|
|
|
62652768 |
Apr 4, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08L 33/12 20130101;
C09K 11/02 20130101; B82Y 20/00 20130101; C09D 11/38 20130101; G02F
1/133719 20130101; G02F 2202/10 20130101; C09K 11/62 20130101; G02F
2001/133715 20130101; G02F 1/1303 20130101; G02F 2202/023
20130101 |
International
Class: |
G02F 1/1337 20060101
G02F001/1337; C09D 11/38 20060101 C09D011/38; C09K 11/62 20060101
C09K011/62; C09K 11/02 20060101 C09K011/02; G02F 1/13 20060101
G02F001/13 |
Claims
1-26. (canceled)
27. A photonic device comprising: a photonic device substrate; and
a crosslinked polymer film on the photonic device substrate, the
crosslinked polymer film comprising: crosslinked polymer chains
comprising polymerized di(meth)acrylate monomers or a combination
of polymerized di(meth)acrylate monomers and mono(meth)acrylate
monomers; a diluent comprising a polyether group and a
crosslinkable group; and quantum dots with hydrophilic ligands
bound to their surfaces, wherein the hydrophilic ligands comprise
ester ligands, ether ligands, or a combination of ester ligands and
ether ligands.
28. The photonic device of claim 27, wherein the device substrate
is a light guide plate and the photonic device is a liquid crystal
display device.
29. The photonic device of claim 27, wherein the crosslinked
polymer film is in a sub-pixel cell of a color filter and the
photonic device is a liquid crystal display device.
30. The photonic device of claim 27, wherein the hydrophilic
ligands comprise polydentate ligands having two or more head groups
bound to the surface of a quantum dot.
31. The photonic device of claim 27, wherein the polydentate
ligands are bidentate ligands having two head groups bound to the
surface of a quantum dot.
32. The photonic device of claim 27, wherein the head groups
comprise carboxylate groups.
33. The photonic device of claim 27, wherein the hydrophilic
ligands comprise ligand backbone chains, the ligand backbone chains
comprising from 16 to 24 carbon atoms.
34. The photonic device of claim 27, wherein the hydrophilic
ligands comprise tail groups that are crosslinkable with the
(meth)acrylate monomer.
35. The photonic device of claim 27, wherein the tail groups
comprise maleimide groups.
36. The photonic device of claim 34, wherein the tail groups
comprise acrylate groups.
37. The photonic device of claim 34, wherein the tail groups
comprise methacrylate groups.
38. The photonic device of claim 34, wherein the tail groups
comprise styrene groups.
39. The photonic device of claim 27, wherein the tail groups
comprise alkylene oxide groups.
40. The photonic device of claim 39, wherein the alkylene oxide
groups comprise ethylene oxide groups or propylene oxide
groups.
41. The photonic device of claim 27, wherein the crosslinkable
group of the diluent comprises a maleimide group, a norbornene
group, or a combination thereof.
42. A method of forming a quantum dot-containing film on a device
substrate, the method comprising: inkjet printing a layer of a
curable ink composition on the surface of a device substrate, the
ink composition comprising: di(meth)acrylate monomers or a
combination of di(meth)acrylate monomers and mono(meth)acrylate
monomers; a diluent comprising a polyether group and a
crosslinkable group; a multifunctional (meth)acrylate crosslinking
agent comprising at least three acrylate functionalities; and
quantum dots with hydrophilic ligands bound to their surfaces,
wherein the hydrophilic ligands comprise ester ligands, ether
ligands, or a combination of ester ligands and ether ligands; and
curing the curable ink composition.
43. The method of claim 42, wherein the ink composition comprises:
30 wt. % to 96 wt. % of the (meth)acrylate monomer; 1 wt. % to 10
wt. % of the diluent comprising a polyether group and a
crosslinkable group; 3 wt. % to 10 wt. % of the multifunctional
(meth)acrylate crosslinking agent; and wt. % to 50 wt. % of the
quantum dots with the hydrophilic ligands bound to their
surfaces.
44. The method of claim 42, wherein the hydrophilic ligands
comprise tail groups that are crosslinkable with the (meth)acrylate
monomer.
45. The method of claim 44, further comprising crosslinking the
tail groups of the hydrophilic ligands with (meth)acrylate groups
of the (meth)acrylate monomer.
46. An ink composition comprising: di(meth)acrylate monomers or a
combination of di(meth)acrylate monomers and mono(meth)acrylate
monomers; a diluent comprising a polyether group and a
crosslinkable group; a multifunctional (meth)acrylate crosslinking
agent comprising at least three acrylate functionalities; and
quantum dots with hydrophilic ligands bound to their surfaces,
wherein the hydrophilic ligands comprise ester ligands, ether
ligands, or a combination of ester ligands and ether ligands.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to: U.S. provisional patent
application No. 62/573,539, filed on Oct. 17, 2017; U.S.
provisional patent application No. 62/634,506, filed on Feb. 23,
2018; and U.S. provisional patent application No. 62/652,768, filed
on Apr. 4, 2018, the entire contents of which are incorporated
herein by reference.
BACKGROUND
[0002] Liquid crystal display (LCD) device technology continuously
evolves with respect to improving the end-user experience. One
aspect of improving the end user experience has been to target
expanding the color gamut of LCD devices. Accordingly, quantum-dot
(QD) technology has been explored with respect to expanding the
color gamut of LCD devices. Generally, various technology solutions
are based on a modification to an LCD device assembly that includes
a polymeric sheet or rod in which QDs are embedded.
SUMMARY
[0003] Ink compositions for forming quantum-dot containing films
are provided. Also provided are methods of forming cured films from
the ink compositions and photonic devices that incorporated the
films as light converting and emitting layers are provided.
[0004] One embodiment of a method of forming a quantum
dot-containing film on a device substrate includes: inkjet printing
a layer of a curable ink composition on the surface of a device
substrate, the ink composition including: 30 wt. % to 96 wt. %
di(meth)acrylate monomers, mono(meth)acrylate monomers, or a
combination of di(meth)acrylate monomers and mono(meth)acrylate
monomers; and 0.1 wt. % to 50 wt. % quantum dots with organic
ligands bound to their surfaces; and curing the curable ink
composition.
[0005] One embodiment of an ink composition includes: 30 wt. % to
96 wt. % di(meth)acrylate monomers, mono(meth)acrylate monomers, or
a combination of di(meth)acrylate monomers and mono(meth)acrylate
monomers; and 0.1 wt. % to 50 wt. % quantum dots with organic
ligands bound to their surfaces.
[0006] One embodiment of a cured film includes a polymerization
product of an ink composition that contains: 30 wt. % to 96 wt. %
di(meth)acrylate monomers, mono(meth)acrylate monomers, or a
combination of di(meth)acrylate monomers and mono(meth)acrylate
monomers; and 0.1 wt. % to 50 wt. % quantum dots with organic
ligands bound to their surfaces.
[0007] One embodiment of a photonic device includes: a photonic
device substrate; and a cured film on the photonic device
substrate, the cured film being a polymerization product of an ink
composition that contains: 30 wt. % to 96 wt. % di(meth)acrylate
monomers, mono(meth)acrylate monomers, or a combination of
di(meth)acrylate monomers and mono(meth)acrylate monomers; and 0.1
wt. % to 50 wt. % quantum dots with organic ligands bound to their
surfaces.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] A better understanding of the features and advantages of the
present disclosure will be obtained by reference to the
accompanying drawings, which are intended to illustrate, not limit,
the present teachings. In the drawings, which are not necessarily
drawn to scale, like numerals may describe similar components in
different views. Like numerals having different letter suffixes may
represent different instances of similar components.
[0009] FIG. 1A is a schematic illustration, which represents
various layers that may be included in an embodiment of an LCD
display device. FIG. 1B is a schematic illustration, which
represents various layers that may be included in another
embodiment of an LCD display device.
[0010] FIG. 2A is a schematic illustration of the upper layers of
an LCD device that includes a QD color filter. FIG. 2B is a
cross-sectional view of the upper layers of the LCD device of FIG.
2A, showing the configuration of the QD color filter. FIG. 2C
illustrates the printing of a QD color filter that includes
scattering nanoparticles (represented by open circles) in its green
sub-pixels, red sub-pixels, and blue sub-pixels. FIG. 2D
illustrates the printing of a barrier or planarization layer over
embodiments of the QD color filter of FIG. 2C. FIG. 2E illustrates
an LCD device utilizing the QD color filter of FIG. 2D.
[0011] FIG. 3A is a schematic illustration of the upper layers of
an LCD device in which the layer stack does not include local
cut-on filters in the sub-pixel cells. FIG. 3B is a cross-sectional
side view of the upper layers of an LCD device according to FIG.
3A, including the blue, green, and red sub-pixels in the QD color
filter. FIG. 3C shows the absorbance spectrum of a global cut-on
filter that absorbs radiation having wavelengths shorter than the
blue emission wavelengths of the device. FIG. 3D shows a
cross-sectional side view of an embodiment of a QD color filter
that includes local light filter layers adjacent to QD-containing
layers in the sub-pixels. FIG. 3E shows the absorbance spectrum of
a red sub-pixel-specific cut-on filter layer; the absorbance
spectrum of the red-emitting QDs in a light-emitting layer; and the
emission spectrum of the red-emitting QDs in the light-emitting
layer for a red sub-pixel. FIG. 3F is a schematic illustration of
the upper layers of an LCD device similar to that of FIG. 2A,
except that the layer stack further includes a global cut-on filter
layer. FIG. 3G is a cross-sectional side view of the upper layers
of the LCD device according to FIG. 3F, including the blue, green,
and red sub-pixels in the QD color filter. FIG. 3H shows the
absorbance spectrum of a global cut-on filter layer; the absorbance
spectrum of a red sub-pixel-specific local cut-on filter layer; the
absorbance spectrum of the red-emitting QDs in a light-emitting
layer; the emission spectrum of the red-emitting QDs in the
light-emitting layer for a red sub-pixel; and the emission spectrum
of blue-emitting QDs in a blue light-emitting layer (or,
alternatively, the blue light emission spectrum for a blue BLU
transmitted through a blue sub-pixel).
[0012] FIG. 4A shows a process of inkjet printing the local light
filter layers in the sub-pixel cells of a QD color filter. FIG. 4B
shows a process of inkjet printing the QD-containing light-emitting
layers in the sub-pixel cells of a QD color filter.
[0013] FIG. 5 shows a cross-sectional side view of a quantum
dot-containing layer disposed between two protective layers for a
color enhancement device.
[0014] FIG. 6 illustrates generally a schematic exploded
perspective view of the components of an LCD device.
[0015] FIG. 7A shows a cross-sectional side view of a substrate
tray for inkjet printing a plurality of device substrates. FIG. 7B
shows a top view of the substrate tray of FIG. 7A.
[0016] FIG. 8 shows a top view of one embodiment of an edge lit CED
having a discontinuous quantum dot-containing layer.
[0017] FIG. 9 shows a cross-sectional side view of the CED of FIG.
8.
[0018] FIG. 10 shows a cross-sectional side of another embodiment
of an edge lit CED having a discontinuous quantum dot-containing
layer.
[0019] FIG. 11 shows a cross-sectional side view of an embodiment
of an edge lit CED having a discontinuous scattering
nanoparticle-containing layer and a separate quantum dot-containing
layer.
[0020] FIG. 12 shows the CED of FIG. 11 having plasmonic scattering
nanoparticles in the quantum dot-containing layer.
[0021] FIG. 13 shows a cross-sectional side view of an embodiment
of an edge lit CED having a continuous scattering
nanoparticle-containing layer, with a variable thickness along its
length, and a separate quantum dot-containing layer.
[0022] FIG. 14 shows a cross-sectional side view of an embodiment
of an edge lit CED having a continuous layer that contains both
quantum dots and scattering nanoparticles and has a variable
thickness along its length.
[0023] FIG. 15 shows a cross-sectional side view of an embodiment
of an edge lit CED having a continuous scattering
nanoparticle-containing layer, with a uniform thickness along its
length, and a separate quantum dot-containing layer.
[0024] FIG. 16 shows a cross-sectional side view of an embodiment
of an edge lit CED having a continuous layer that contains both
quantum dots and scattering nanoparticles and has a uniform
thickness along its length.
[0025] FIG. 17 shows a cross-sectional side view of an embodiment
of a back lit CED having a discontinuous quantum dot-containing
layer.
[0026] FIG. 18 shows a cross-sectional side view of an embodiment
of a back lit CED having a discontinuous scattering
nanoparticle-containing layer and a separate quantum dot-containing
layer.
[0027] FIG. 19 shows a cross-sectional side view of an embodiment
of a back lit CED having a continuous scattering
nanoparticle-containing layer, with a uniform thickness along its
length, and a separate quantum dot-containing layer.
[0028] FIG. 20 shows a cross-sectional side view of an embodiment
of a back lit CED having a continuous layer that contains both
quantum dots and scattering nanoparticles and has a uniform
thickness along its length.
[0029] FIG. 21 shows a cross-sectional side view of an embodiment
of a back lit CED having a continuous scattering
nanoparticle-containing layer, with a thickness modulation along
its length, and a separate quantum dot-containing layer, with an
optional thickness modulation along its length.
[0030] FIG. 22 is a schematic illustration of a method for inkjet
printing layers containing quantum dots and scattering
nanoparticles on a device substrate.
[0031] FIG. 23 is a schematic illustration of a method for forming
a sealing layer on a substrate and, optionally, also a barrier
layer.
[0032] FIG. 24 is a schematic illustration of a method of printing
one or more layers of a CED between the sealing banks of a sealing
layer and then sealing the CED layers.
[0033] FIG. 25 shows an example of a monodentate ligand having a
carboxylic acid head group and a methacrylate tail group.
[0034] FIG. 26 shows a method of synthesizing a bidentate ligand
having two carboxylic acid head groups and a methacrylate tail
group.
[0035] FIG. 27 shows a method of synthesizing another bidentate
ligand having two carboxylic acid head groups and a methacrylate
tail group.
[0036] FIG. 28 shows a method of synthesizing a bidentate ligand
having two carboxylic acid head groups and a maleimide tail
group.
[0037] FIG. 29 shows the different maleimide amines that can be
used to replace a (meth)acrylate tail group with a maleimide tail
group.
[0038] FIG. 30 shows a method of synthesizing a bidentate ligand
having two carboxylic acid head groups and a maleimide tail group
starting with the bidentate ligand of FIG. 26.
[0039] FIG. 31 shows a method of synthesizing a bidentate ligand
having two carboxylic acid head groups and a maleimide tail group
starting with the bidentate ligand of FIG. 27.
[0040] FIG. 32 is a schematic illustration of the crosslinking of a
QD into a cured polymeric film.
[0041] FIG. 33 shows the chemical structures of various organic
ligands having non-crosslinking tail groups.
[0042] FIG. 34 is a schematic illustration of the stabilization of
a QD into an ink composition through the use of a diluent.
[0043] FIG. 35 is a schematic diagram of a ligand exchange
mechanism.
DETAILED DESCRIPTION
[0044] Ink compositions for forming QD-containing films are
provided. Also provided are methods for forming the QD-containing
films via inkjet printing and photonic devices that incorporate the
QD-containing films. The QD-containing films can be incorporated as
light-emitting layers in a variety of optoelectronic devices.
Although the description that follows illustrates the use of the
QD-containing films as color filter layers and color enhancement
layers in devices such as LCDs or organic light-emitting diodes
(OLEDs), the QD-containing films can be incorporated into other
devices that include a QD-containing light-emitting layer.
Display Devices Having Color Filters Incorporating a QD-Containing
Layer
[0045] FIG. 1A is a schematic illustration that represents various
layers that may be included in an LCD display device. For various
display devices, for example, for various LCD devices, and for some
types of organic light emitting diode (OLED) devices, light is
directed from a source of white light located in back of the
individual sub-pixels of a color filter array. The sub-pixels can
be, but are not limited to, red (R) sub-pixels, green (G)
sub-pixels, and/or blue (B) sub-pixels. For LCD devices, the light
source may be a back-light source that illuminates many sub-pixels
in a color filter array at once, at a common brightness which can
be adjusted based on the image to be displayed. The light
transmitted through each of the sub-pixels of a color filter array
can be further modulated by a corresponding liquid crystal filter
associated with each sub-pixel of a color filter array. The liquid
crystal filter can be controlled by, for example, a transistor
circuit. In the case of OLED devices, the light supplied to each of
the sub-pixels of a color filter array typically comes from a white
OLED device and the brightness of each sub-pixel is modulated by a
transistor circuit. For either various embodiments of LCD devices
or OLED devices, each sub-pixel of a color filter array contains a
light filtering media that transmits light only within a prescribed
electromagnetic wavelength bandwidth associated with the sub-pixel
color. Manufacturing a conventional color filter array can be done
using, for example, photolithographic techniques, which are complex
processes requiring many separate sequences of, for example,
blanket coating, photo-exposure, and development to fabricate both
the light blocking "black matrix" material in between the
sub-pixels, as well as the individual color filter material
deposition sequences (e.g. one each for R, G, and B). Though FIG.
1A indicates an indium tin oxide (ITO) layer, which in various
embodiments can be coated on the polarizer surface positioned
towards the liquid crystal, various embodiments of an LCD display
device do not include an ITO coating on a polarizer. The device
might have an anti-glare layer to reduce glare caused by ambient
light.
[0046] FIG. 1B is a schematic illustration that represents various
layers that may be included in an LCD display device according to
the present teachings. In the device of FIG. 1B, the color filter
shown in FIG. 1A has been replaced by a color filter layer
fabricated using QDs. The QDs are small crystalline particles that
absorb incident radiation having a first wavelength, or a first
range of wavelengths, and convert the energy of the radiation into
light having a different wavelength, or a different range of
wavelengths, which is emitted from the QDs within a very narrow
part of the optical spectrum. Thus, by incorporating QDs of
appropriates sizes and materials in appropriate concentrations and
ratios into a light-emitting device layer, that layer can be
designed to alter the absorption and/or emission spectra of a
photonic device that incorporates the layer. Thus, the
QD-containing color filter layers are so called because they
"filter" incoming light having a first wavelength or wavelength
range, such as ultraviolet or blue light, by converting at least a
portion of it into light having a different wavelength or
wavelength range, such as red and/or green light. On a first side
of a QD-containing color filter, as depicted in FIG. 1B, there can
be a polarizer layer.
[0047] An LCD device may also utilize an anti-photoluminescent
layer in conjunction with a QD-containing color filter (referred to
herein as a QD color filter). Since the color filter sub-pixels
that utilize QDs are at the front of the display, it is desirable
to avoid having ambient light act as a source of excitation for QDs
in the color filter layer. Accordingly, various embodiments of LCD
devices utilize various local and global filter layers acting as
anti-photoluminescent layers. Similarly, this layer of filters can
also be utilized to prevent excess blue light (which has not been
absorbed and converted by the QD layer) to be transmitted and thus
decrease the color gamut of the display. Moreover, as will be
described in more detail herein, inkjet printing can be used to
fabricate the QD-containing layers of various embodiments of the QD
color filters, as well as various anti-photoluminescent layers for
such devices.
[0048] FIG. 2A is a schematic illustration of the upper layers of
an LCD device of the type shown in FIG. 1B. FIG. 2B is a
cross-sectional view of the upper layers of the LCD device. As
noted for FIG. 1B, on a first side of a QD-containing layer of the
QD color filter there can be a polarizer layer. In various
embodiments of a QD-containing color filter as illustrated
generally herein, for FIG. 1B, FIG. 2A, FIG. 2B, FIG. 2E, FIG. 3A,
FIG. 3B, FIG. 3F, and FIG. 3G, a conductive film, such as an ITO
film, can be coated on the polarizer layer, while in other
embodiments, the device may not require an ITO coating. In various
embodiments of an LCD device for which a conductive coating is
utilized, other conductive, transparent materials can also be used,
for example, but not limited by, fluorine-doped tin oxide (FTO),
doped zinc oxide, and graphene, as well as combinations of such
materials can be used. As shown in FIG. 2B, the QD color filter
includes a plurality of sub-pixel cells defined by sub-pixel banks
(depicted as thick black sections). The sub-pixels formed in the
sub-pixel cells include red sub-pixels (designated with an "R" in
FIG. 2B), green sub-pixels (designated with a "G" in FIG. 2B), and
blue sub-pixels (designated with a "B" in FIG. 2B). Each red
sub-pixel includes a red light-emitting layer containing
red-emitting QDs dispersed in a polymer matrix. Similarly, each
green sub-pixel includes a green light-emitting layer containing
green-emitting QDs dispersed in a polymer matrix. In some
embodiments of the LCD device in which the BLU is an ultraviolet
light, each blue sub-pixel includes a blue light-emitting layer
containing blue-emitting QDs in a polymer matrix. In other
embodiments of the LCD device in which the BLU is a blue light, the
blue sub-pixels in the QD color filter need not include QDs, but
can, optionally, include a polymer matrix that at least partially
transmits the blue light from the BLU. The polymer matrices in the
sub-pixels are capable of transmitting light across at least
certain portions of the visible spectrum. By way of illustration,
BLU may be composed of one or more blue LEDs, including one or more
blue OLEDs.
[0049] In the LCD device of FIG. 2B, an anti-photoluminescent layer
is provided in the form of a global cut-on filter layer and a local
cut-on filter layers. More information about the structure of
global and local cut-on filter layers (also referred to as global
light filter layers and local light filter layers) is provided in
FIGS. 3A, 3B, 3F, and 3G and their accompanying description
below.
[0050] In addition to the QDs, the light-emitting layers of the
sub-pixels can contain scattering nanoparticles (SNPs), which may
be geometric scattering nanoparticles (GSNPs), plasmonic scattering
nanoparticles (PSNPs), or a combination thereof. It should be noted
that, although the PSNPs and GSNPs will generally have at least one
nanoscale dimension--that is, at least one dimension of not greater
than about 1000 nm, the nanoparticles need not be round particles.
For example, the nanoparticles can be elongated particles, such as
nanowires, or irregularly shaped particles. Such scattering
nanoparticles can also be included in the matrix material of blue
sub-pixels that do not contain any QDs. Scattering by GSNPs is
accomplished by refraction at the surface of the particle. Examples
of GSNPs include metal oxide nanoparticles, such as nanoparticles
of zirconium oxide (i.e. zirconia), titanium oxide (i.e. titania)
and aluminum oxide (i.e. alumina) A PSNP is characterized in that
incident light excites an electron density wave in the nanoparticle
that creates a local oscillating electric field extending out from
the surface of the nanoparticle. In addition to the scattering
effect of the particle, if the PSNP is in close proximity to one or
more QDs, this electric field can couple to the QDs, thereby
enhancing the absorption of the QD layer. Examples of PSNPs include
metal nanoparticles, such as nanoparticles of silver and gold.
[0051] FIG. 2C shows an example of a QD color filter 160 that
includes GSNPs that can be formed using inkjet printing into a
plurality of sub-pixel cells 115 formed in substrate 110. As
depicted in FIG. 2C, an ink composition containing green QDs
(CFI.sub.G), an ink composition containing blue QDs (CFI.sub.B),
and an ink composition containing red QDs (CFI.sub.R) can be
printed to form to form the green, blue, and red light-emitting
layers, respectively, of QD color filter 160. As illustrated
generally in FIG. 2C, the various QD inks can include SNPs
(represented by open circles)), which can be incorporated in the
green sub-pixels, the red sub-pixels, and the blue sub-pixels. (As
depicted in FIG. 2C, the green QDs are represented by the smaller
solid circles and the red QDs are represented by the larger solid
circles.) The SNPs provide enhanced light absorption and extraction
by acting as light scattering centers in the polymer matrices.
Including SNPs in combination with the QDs can increase the color
conversion efficiency of a QD-containing sub-pixel by increasing
photon scattering in the interior of the light-emitting layer, so
that there are more interactions between the photons and the QDs
and, therefore, more light absorption by the QDs.
[0052] In embodiments of QD color filters that include
blue-emitting QDs in the blue sub-pixels, SNPs (for example, GSNPs)
could also be included in those sub-pixels. However, even blue
sub-pixels that lack QDs can include SNPs dispersed in a polymer
matrix to provide isotropic blue light emission from the blue
sub-pixels that is equivalent to, or nearly equivalent to, the
isotropic red and green light emission that is provided by the red
and green sub-pixels, such that the optical appearance of the
emitted blue light (e.g., haze and specular emission) is similar to
that of the emitted red and green light. However, in order to avoid
unwanted scattering of ambient light in the sub-pixels, some
embodiments of the light-emitting layers are free of SNPs.
[0053] The QDs and, if present, GSNPs and/or PSNPs can be
incorporated into the light-emitting layer of a sub-pixel by
including them in an ink composition, depositing them by inkjet
printing the ink composition as a layer in a sub-pixel cell, and
drying and/or curing the printed ink composition. By way of
illustration, an effective scattering nanoparticle size in the
range from about 40 nm to about 1 .mu.m, depending on the type of
scattering, can be selected for use in a jettable ink. The GSNPs
will typically be larger than the PSNPs and both types of particles
will generally be larger than the QDs. By way of illustration only,
in various embodiments of the ink compositions and the layers
formed therefrom, the GSNPs have an effective size in the range
from about 100 nm to about 1 .mu.m and the PSNPs have an effective
size in the range from about 10 nm to about 200 nm.
[0054] FIG. 2D illustrates generally a process for forming a
polymeric layer on various embodiments of QD color filter 160.
According to the present teachings, polymeric layer 170 can be
formed after the formation of the QD-containing light-emitting
layer of the QD color filter. According to the present teachings,
polymeric layer 170 can be a planarization layer. In various
embodiments, polymeric layer 170 can be a planarization layer that
may additionally act as a protective layer. For various embodiments
of a QD color filter, as will be described in more detail for FIG.
2E, polymeric layer 170 can be formed over an inorganic barrier
layer. As will be described in more detail herein, polymeric layer
170 can be formed from a polymer-forming ink composition that, when
subsequently cured or dried, can form polymeric layer 170.
Polymeric layer 170 can be, for example, between about 1 .mu.m
(micron) to about 5 .mu.m (micron) in thickness. As illustrated
generally in FIG. 2D, there can be surface topology occurring as a
result of the sub-pixel cell structures in conjunction with, for
example, formation of a meniscus occurring in the sub-pixel cells.
As such, inkjet printing can be done to compensate for the
variation in surface topology, for example, by printing more of a
polymer-forming ink composition over areas where there are
depressions, and less of a polymer-forming ink composition over
areas that are raised relative to the areas of depression.
[0055] In various embodiments of a polymer-forming ink composition
of the present teachings that can be used to form polymeric layer
170 of FIG. 2D, particles of various shapes and materials can be
added to an ink composition for the purpose of providing refractive
index adjustment of a polymeric layer formed over the QD-containing
sub-pixels. In various embodiments of such a polymeric-film forming
ink composition, metal oxide nanoparticles, such as zirconium
oxide, aluminum oxide, titanium oxide, and hafnium oxide of size,
for example, between about 5 nm to about 50 nm, can be added to an
ink. For various embodiments of such a polymeric-film forming ink
composition, graphene nanostructures, such as graphene nanoribbons
and graphene platelets, can be added to an ink composition in order
to substantially reduce the water vapor permeation through the
polymeric layer. According to the present teachings, graphene
platelets can have dimensions of, for example, between about 0.1 nm
to about 2 nm in thickness and between about 100 nm to about 1
.mu.m (micron) in diameter, while graphene nanoribbons can have
dimensions of between, for example, about 0.1 nm to 10 nm in
thickness and length of between about 1 nm to about 20 nm. Loading
of various graphene nanoparticles in an ink composition of the
present teachings can be between about 0.1% and 1.0%.
[0056] FIG. 2E illustrates generally a portion of an LCD device,
for example, as depicted in FIG. 1B, depicting planarizing layer
170 of QD color filter 160 oriented towards a polarizer, for which
an ITO layer as previously discussed herein can be optional. In
various embodiments of QD color filter 160, planarization layer can
be, for example, a polyethylene terephthalate (PET) film, an
acrylate-based polymeric film, or the like. QDs embedded in the
QD-containing sub-pixels of QD color filter 160 are known to
degrade when exposed to atmospheric gases, such as water vapor,
oxygen and ozone. Thus, in various embodiments of the QD color
filter, polymeric layer 170 can be coupled to an inorganic barrier
layer that protects the QD-containing layer from the ingress of
water vapor, oxygen, and/or ozone. The inorganic barrier layer,
which can be disposed above or below polymeric layer 170, can be
comprised of inorganic materials, such as metal oxides, metal
nitrides, metal carbides, metal oxynitrides, metal oxyborides, and
combinations thereof. For example, the inorganic barrier layer can
be composed of a material such as a silicon nitride material
(SiN.sub.x), aluminum oxide (Al.sub.2O.sub.3), titanium oxide
(TiO.sub.2), hafnium oxide (HfO.sub.2), or a silicon oxynitride
material (SiO.sub.xN.sub.y), or combinations thereof. According to
the present teachings, layer 170 can be a combination of a first
barrier layer composed of at least one inorganic barrier material
as described herein, followed by a second polymeric layer. If
present, the polymeric planarization layer and the barrier layer
should be capable of transmitting light in the visible region of
the electromagnetic spectrum. Polymeric protective layers can be
deposited using inkjet printing, as exemplified by U.S. Patent
Publication 2016/0024322.
[0057] To prevent excitation of the quantum dots by ambient light
three embodiments of the CED are proposed: (1) a CED containing
only a global cut-on filter; (2) a device containing only local
cut-on filters; and (3) a device containing both global and local
cut-on filters.
[0058] Some embodiments of the LCD devices will include a global
cut-on filter layer, without any local cut-on filters. One such
device is shown schematically in FIGS. 3A and 3B. FIG. 3A is a
schematic illustration of the upper layers of an LCD device. FIG.
3B is a cross-sectional side view of the upper layers, including
the blue, green, and red sub-pixels in the QD color filter layer.
The global cut-on filter can be deposited on either side of the
glass substrate. Ambient light with shorter wavelengths than the
blue emission will be blocked from entering the QD layer and,
therefore, will not excite the red and green QDs. This global
cut-on filter layer may be continuous and un-patterned, and may be
disposed on either side of the substrate of the QD color filter.
The global cut-on filter layer is desirably of high optical
performance with a steep cut-on filter characteristic.
[0059] FIG. 3D shows a cross-sectional side view of an embodiment
of a QD color filter that includes a local light filter layer
disposed between the substrate and the light-emitting surface of
the QD-containing layer in each sub-pixel cell. These local light
filter layers serve to filter out ambient light incident on the
device that would otherwise enter the QD-containing layers and be
absorbed by the QDs, creating unwanted photoluminescence and
degrading the optical quality of the LCD. By the same mechanism,
these local light filters can also filter out any excess blue light
from the BLU which has not been absorbed by the QD layer and which
would otherwise cause a diminished color saturation and diminished
color gamut for the display. As illustrated in FIG. 3E, the local
light filter layers (LFs) act as a sub-pixel-specific cut-on
filter; absorbing radiation at wavelengths below the emission
wavelengths of the QDs in the QD-containing light-emitting layer
and transmitting radiation at wavelengths at and above the emission
wavelengths of the QD-containing light-emitting layer. In FIG. 3E,
the local light filter layer is illustrated for a red sub-pixel.
The local light filter layers include light absorbers with the
appropriate light absorbing properties. Thus, a local light filter
layer for a red sub-pixel (LF.sub.R) will include a light absorber
that absorbs radiation at wavelengths below the red-light emission
wavelengths of the red-emitting QDs in the red-emitting sub-pixel
and transmits radiation at wavelengths at and above the red-light
emission wavelengths of the red-emitting QDs in the red-emitting
sub-pixel. Similarly, a local light filter layer for a green
sub-pixel (LF.sub.G) will include a light absorber that absorbs
radiation at wavelengths below the green light emission wavelengths
of the green-emitting sub-pixel and transmits radiation at
wavelengths at and above the green light emission wavelengths of
the green-emitting sub-pixel. And, if blue QDs are being used, a
local light filter layer for a blue sub-pixel (LF.sub.B) will
include a light absorber that absorbs radiation at wavelengths
below the blue light emission wavelengths of the blue-emitting
sub-pixel and transmits radiation at wavelengths at and above the
blue light emission wavelengths of the blue-emitting sub-pixel.
Local light filter layers could be omitted if the blue sub-pixels
are free of QDs, in which case the sub-pixel cells corresponding to
the blue sub-pixels could be completely filled with a matrix
material that is optically transparent to blue light. The local
filters can be deposited using, for example, inkjet printing; the
light absorbing materials would be deposited into the sub-pixel
cell and dried/cured before the QD-containing light-emitting layer
of the QD color filter was deposited in the sub-pixel cell. In this
way, two discrete layers could be formed within a sub-pixel cell,
with the local cut-on filter layer facing the outside of the device
after assembly and, thus, protecting the QD color filter layer from
unwanted excitation.
[0060] In a variation of the LCD shown in FIG. 2B, the local light
filter layers can be formed underneath their respective sub-pixel
cells, rather than within those sub-pixel cells. In this variation,
the local light filter layers could be formed in a pattern over the
sub-pixel cells using, for example, photolithography.
[0061] In some embodiments of the LCD devices, a global cut-on
filter layer is combined with local cut-on filter layers. In such
devices ambient light having wavelengths shorter than the blue
emission wavelengths of the display device will be blocked by the
global cut-on filter layer. However, light having wavelengths
longer than the blue emission wavelengths, but shorter than the
emission wavelengths of the QDs at the respective sub-pixel
location can still cause excitation of the QDs. A local cut-on
filter which blocks only this particular part of the optical
spectrum can, in conjunction with a global cut-on filter, eliminate
(or significantly reduce) the excitation of the QD by ambient
light. At the same time, a local cut-on filter with said properties
will block excess blue light from the BLU, which was not absorbed
by the QD color filter. By this process the color saturation and
the color gamut of the display can be enhanced. An embodiment of a
display device that incorporates a local cut-on filter layer and a
global cut-on filter layer is illustrated in FIGS. 3F and 3G, and
the spectral function of the system is shown in FIG. 3H.
[0062] FIG. 3F is a schematic illustration of the upper layers of
an LCD device. FIG. 3G is a cross-sectional side view of the upper
layers, including the blue, green, and red sub-pixels in the QD
color filter. In this embodiment of the LCD device, the QD color
filter has the same structure as that shown in FIG. 3D and the
global cut-on filter layer overlies all of the sub-pixel cells. As
discussed above, the global cut-on filter layer acts as an
additional filter for ambient incident light; absorbing radiation
at wavelengths below the shortest emission wavelengths of the
device, for example, below the blue emission wavelengths of the
device. In the embodiment of the LCD shown in FIGS. 3F, 3G and 3H,
the red sub-pixels include local cut-on filter layers that acts as
band-pass filters for ambient incident light. Analogous local light
filter layers can be included in the green and/or blue
sub-pixels.
[0063] In addition to, or as an alternative to, providing local
filters as layers separate from the QD-containing layers in the QD
color filters, the light absorbing materials can be incorporated
into the QD color filter layer by including them in an
QD-containing ink composition, inkjet printing the ink composition
as a QD-containing layer in a sub-pixel cell, and curing the
printed ink composition. It should be understood that, although not
depicted here, the light absorbing materials, QDs, and, optionally,
any GSNPs and/or PSNPs can be included in a single ink composition
and printed as a single layer in a sub-pixel cell in which the
light absorbers and QDs are uniformly distributed. However, in such
embodiments, it may be desirable to select the light absorbing
material and the polymer matrix material such that they do not
fully prevent the transmission of blue light. Suitable light
absorbers for inclusion in the local light filter layers include
organic dye molecules, such as azo dyes, inorganic pigments, and
combinations thereof.
[0064] A process of inkjet printing a QD color filter including a
plurality of green, red, and blue sub-pixels is shown schematically
in FIG. 2C, whereby a green color filter ink composition,
CFI.sub.G, is printed directly into the sub-pixel cell for a green
sub-pixel using a first inkjet printing nozzle, a blue color filter
ink composition, CFI.sub.B, is printed directly into the sub-pixel
cell for a blue sub-pixel using a second inkjet printing nozzle,
and a red color filter ink composition, CFI.sub.R, is printed
directly into the sub-pixel cell for a red sub-pixel using a third
inkjet printing nozzle. Alternatively, the different color
sub-pixels can be printed sequentially using the same inkjet
printing nozzle. Each of the color filter ink compositions contains
its respective color emitting QDs in an organic polymer forming
material, an organic solvent, or mixture thereof. The curable
organic polymer forming materials cure to form a polymer matrix
material and can include various organic monomers, oligomers,
and/or polymers, as discussed in more detail below. In addition,
the color filter ink compositions can include a crosslinking agent,
a photoinitiator, or both.
[0065] A process of inkjet printing a QD color filter having local
light filter layers is shown schematically in FIGS. 4A and 4B,
whereby the local light filter layers are printed in the sub-pixel
cells prior to printing the QD-containing light-emitting layers. As
shown in FIG. 4A, a green local light filter ink composition,
LFI.sub.G, is printed directly into the sub-pixel cell for a green
sub-pixel using a first inkjet printing nozzle (or a first set of
nozzles), a blue local light filter ink composition, LFI.sub.B, is
printed directly into the sub-pixel cell for a blue sub-pixel using
a second inkjet printing nozzle (or a second set of nozzles), and a
red local light filter ink composition, LFI.sub.R, is printed
directly into the sub-pixel cell for a red sub-pixel using a third
inkjet printing nozzle (or a third set of nozzles). Alternatively,
the different color sub-pixels can be printed sequentially using
the same inkjet printing nozzle (set of nozzles). Each of the local
light filter ink compositions contains its respective light
absorbing material, one or more polymer binder precursors, a
solvent, or mixture thereof, as discussed in more detail below. The
curable polymer binder precursors cure to form a matrix material
and can include various organic monomers and/or oligomers. In
addition, the local light filter ink compositions can include a
crosslinking agent, a cure initiator, such as a photoinitiator, or
both. Once the sub-pixel-specific local light filter layers are
formed in the bottoms of their respective sub-pixel cells, the
QD-containing light emitting layers can be printed over the cured
or dried local light filter layers, as illustrated in FIG. 4B.
After the final assembly of the display, the color filter substrate
faces outside and the QD-containing layers face the interior of the
display.
[0066] In various alternative processes for printing the
QD-containing layers and the layers containing the light absorbing
materials a single ink composition containing a mixture of the QDs
and the light absorbing materials is applied (e.g., inkjet printed)
as a single layer initially and dried in such a manner that a layer
containing the light absorbing materials separates from a layer
containing the QDs, resulting in a two-layer structure. For
example, if the QDs are capped with long carbohydrate ligands, it
is possible to phase separate them out with a suitable solvent
before the remaining light absorber-containing portion of ink
composition dries. Alternatively, the solubility of the light
absorbing material could be selected such that this material (or
the matrix in which it is dissolved) crashes out first, due to the
solubility limits of the material.
QD-Containing Color Enhancement Layers
[0067] The present inventors have recognized that inkjet printing
techniques can be used to provide innovative QD-containing CEDs.
Various CEDs of the present teachings include quantum dots
dispersed in a matrix. The CEDs can be formed as continuous or
discontinuous inkjet printed layers using QD-containing inkjet
printable ink compositions. As a result, the composition, geometry,
and location of the CEDs can be precisely tailored for a variety of
device applications. By incorporating QDs of appropriate sizes and
materials in appropriate concentrations and ratios into the CEDs,
the CEDs can be designed to alter the absorption and/or emission
spectra of photonic devices that incorporate the CEDs.
[0068] A cross-sectional view of a basic embodiment of a CED is
depicted schematically in FIG. 5. This CED includes a QD-containing
layer 572 that contains a plurality of QDs 580, 590 in a matrix
585, such as a polymer matrix. QD-containing layer 572 optionally
can be positioned between first and second protective layers, 574A
and 574B, respectively. QD-containing layer 572, as depicted, has a
plurality of green-emitting QDs 580, shown as smaller spheres, as
well as a plurality of red-emitting QDs 590, shown as larger
spheres. As shown in FIG. 5, green-emitting QDs 580 and
red-emitting QDs 590 are dispersed through matrix 585, which can
be, for example, a polymeric matrix capable of transmitting light
in the visible spectrum. Moreover, first and second protective
layers 574A and 574B provide protection for the QDs embedded in
QD-containing layer 572, given the sensitivity of QDs to
atmospheric gases, such as water vapor, oxygen and ozone. In
various embodiments of the CED, first and second protective layers
574A and 574B can be a polymeric film, such as polyethylene
terephthalate (PET), (meth)acrylate-based polymeric film, or the
like, or an inorganic barrier layer, or combination of the two.
Like QD matrix 585, the protective film needs to be capable of
transmitting light in the visible spectrum.
[0069] Depending on the devices into which they are incorporated,
the CEDs of the present teachings can enhance the visual experience
of an end user by enhancing the color gamut of light output by the
device; and/or enhance the efficiency of the device to provide
improved optical clarity and brightness to an end user. Similarly,
the layer can also improve the absorption efficiency of radiation
incident on the device. For example, a QD-containing layer can be
inkjet printed onto a surface of a photovoltaic cell, such that a
portion of the radiation incident on the cell is converted into
wavelengths that are more efficiently absorbed by the photoactive
material of the cell. By way of illustration, blue and/or
ultraviolet (UV) light incident upon the QD-containing layer in a
silicon solar cell can be absorbed by the QDs and emitted as red
light, which is more efficiently absorbed by the silicon. In the
photovoltaic cells, the QD-containing layer can be printed directly
onto the photoactive material or on the surface of another
component, such as an anti-reflection coating or an electrode.
[0070] In the LCD devices, the QD-containing layer can be printed
directly onto a light guide surface or onto the surface of another
component, such as a reflector, a diffuser, or a polarizer. FIG. 6
illustrates generally an exploded perspective view of one
embodiment of an LCD device 650 into which a CED can be
incorporated. LCD device 650 can have LCD panel 652. LCD panel 652
itself can be comprised of many component layers, which can
include, for example, but not limited by, a thin film transistor
(TFT) layer, a liquid crystal layer, a color filter array (CFA)
layer, and a linear polarizer. Additional component layers can
include another polarizer 654, first and second brightness
enhancement films 656A and 656B, respectively, and reflector film
658. LCD device 650 includes light guide plate 660, which can
include a plurality of LED devices 662 positioned proximal to an
end of light guide plate 660 as sources of light that can be
propagated through light guide plate 660. For various LCD devices,
the LED devices associated with a light guide plate can be either
white or blue LED sources, though as will be discussed herein
subsequently, for LCD device 650, the plurality of LED devices 662
can be blue emitting LEDs with, for example, but not limited by, an
emission line at 445 nm.
[0071] A plurality of device layers can be inkjet printed onto a
plurality of substrates simultaneously, or in rapid succession,
with or without a controlled delay between the successive printing
steps using a substrate tray that holds the substrates in place and
that moves with respect to the inkjet printhead during the inkjet
printing process. This is illustrated schematically in FIG. 7A and
FIG. 7B, which show a cross-sectional side view and a top view,
respectively, of a substrate tray 702 holding a plurality of device
substrates 704 disposed in an array. Device substrates 702 can be,
for example, light guides, reflectors, diffusers, polarizers,
layers of anti-reflective material, or electrodes. The shape of the
substrate is not limited to rectangular shapes. For example,
wafers, as used in the semiconductor industry, can also be
processed. Substrate tray 704 includes a plurality of securing
features that prevent device substrates 704 from sliding around on
the surface of the substrate tray when the tray is in motion. The
securing features can take on a variety of forms. In the embodiment
shown in FIGS. 7A and 7B, the securing features are a plurality of
recessed areas 706 defined in the upper surface 708 of substrate
tray 704. A device substrate can be placed in each recessed area
without the need for an additional mechanism for fixing the
substrates to the tray. Alternatively, the securing features can
include locking mechanisms that fix the substrates to the tray
and/or provide for precise positioning and alignment of the
substrates in select locations on the tray. For example, a
spring-loaded pin can be placed between device substrate 704 and
the wall of its recessed area 706 to prevent the substrate from
moving around in the recessed area.
[0072] If the alignment of the device substrates on the tray is
critical and the tolerances of the securing features are not
sufficiently high, the device substrates can be placed in precise
alignment on the substrate trays using alignment sensors with
sensory feedback and then locked into place on the tray by a
locking mechanism. This sensor-aided alignment can be carried out
after the substrate tray has been transferred to the inkjet printer
but prior to inkjet printing the QD-containing layers or before the
substrate tray has been transferred to the inkjet printer.
[0073] In addition to the QDs, the QD-containing layer can contain
GSNPs, PSNPs, or a combination thereof. Alternatively, the GSNPs
and/or PSNPs can be contained in one or more separate layers in the
CED. When the GSNPs and/or PSNPs are incorporated in a
QD-containing layer they can improve the conversion performance of
that layer. In addition, the GSNPs and PSNPs provide enhanced light
extraction, by acting as light scattering centers in the matrix of
the QD-containing layer and/or in a separate layer in the CED.
Including GSNPs and/or PSNPs in combination with the QDs can
increase the color conversion efficiency of a CED by increasing
light scattering in the interior of the quantum dot layer, so that
there are more interactions between the photons and the scattering
particles and, therefore, more light absorption by the QDs. Like
the QDs, the GSNPs and PSNPs can be incorporated into a CED by
including them in an ink composition, and depositing them by inkjet
printing the ink composition as a layer, as described above with
respect to QD color filters.
[0074] The QD-containing layers and/or scattering
nanoparticle-containing layers in a CED can be continuous or
discontinuous and can have a uniform distribution or a non-uniform
distribution of QDs and/or scattering particles along their lengths
and/or through their thicknesses. Similarly, QD-containing layers
and/or scattering particle-containing layers in a CED can have a
uniform or a non-uniform thickness along their lengths. The use of
a non-uniform QD or scattering nanoparticle distribution or a
non-uniform layer thickness can be used, for example, to offset a
non-uniform intensity distribution of the QD-exciting light in the
layer. For example, the use of a gradient concentration of the QDs
and/or the scattering nanoparticles in a given layer can provide a
more uniform light emission and/or color spectrum along the length
of a CED by compensating for any non-uniformity in the intensity of
the light entering the QD-containing layer. This is illustrated for
various embodiments of a CED in an LCD panel assembly in the
embodiments that follow.
[0075] For simplicity, and with the exception of FIG. 12, in the
figures described below, scattering nanoparticles are represented
with open circles and quantum dots are represented by solid
(filled) circles. The scattering nanoparticles represented by the
open circles can be only GSNPs, only PSNPs, or a mixture of GSNPs
and PSNPs and are referred to generically as SNPs. In addition,
some of the embodiments illustrated in the figures include a
QD-containing layer that does not include any SNPs. Although not
depicted in all of the figures, any QD-containing layer can also
include SNPs (GSNPs, PSNPs, or both) as an alternative to--or in
addition to--any separate SNP-containing layers.
[0076] FIG. 8 is a top plan view of CED 800 that incorporates QD
materials into the subassembly of an LCD device using inkjet
printing. Similar to the combination of light guide plate 660 and
QD-containing layer 670 of FIG. 6, CED 800 can be used as a
subassembly to achieve the same improvements. In this embodiment,
CED 800 has a non-uniform QD-containing layer composed of a
patterned array of QD-containing structures 822 deposited in
confinement regions upon light guide plate 810. Inkjet printing is
used to locally deposit QD-containing structures 822 onto first
surface 811. The local density of these structures is controlled by
the inkjet printing pattern. The number of QDs per QD-containing
structure can be controlled by the QD concentration in the ink
composition, by the inkjet drop volume, and/or by the number of
inkjet drops per QD-containing structure. Surface treatment of
first surface 811 before the printing process can be used to tailor
the local wetting properties on the surface and, as a result, can
control the size and the shape of the printed QD-containing
structures. The surface treatment can be performed in a patterned
fashion to increase printing resolution and structure profile.
Light guide plate 810 is illuminated by LEDs 812 positioned at a
near end edge 815. In this edge lit configuration, the intensity of
the light in light guide plate 810 decreases along its length. As a
result, light that is out-coupled from light guide plate 810 enters
QD-containing structures 822 with a non-uniform light intensity
distribution, wherein the intensity of the light out-coupled into
the QD-containing structures closer to near end edge 815 is greater
than the intensity of the light out-coupled into those that are
close to far end edge 816. For this reason, the local density of
QD-containing structures 822 has a gradient along the length of
light guide plate 810, with a lower density of QD-containing
structures 822 at near end edge 815 and a higher density of
QD-containing structures 822 at the opposite edge of light guide
plate 810. This arrangement of the QD-containing structures can
compensate for the decrease in light intensity along the length of
light guide plate 810, thereby generating a more uniform emission
along the length of the CED. Though FIG. 8 depicts an ordered array
of QD-containing structures 822 having a density gradient
distribution, for various embodiments of CEDs of the present
teachings utilizing QD-containing structures, any pattern of
confinement regions having any of a variety of shapes and aspect
ratios can be formed on the first surface 811 of light guide plate
810. Moreover, the size and packing density of the QD-containing
structures can be determined by the manner in which a defined
pattern of ink confinement regions is fabricated. In various
embodiments of an array of QD-containing structures, the array is
fabricated to provide a microlens array.
[0077] FIG. 9 is a schematic cross-sectional view of CED 800. In
the devices of FIG. 8 and FIG. 9, LED 812 can be a blue-emitting
LED with, for example, but not limited by, an emission line at 445
nm. The QD-containing structures 822 in this embodiment of the CED
are dome-shaped, but they can have any arbitrary shape. Each
structure contains a plurality of QDs, where smaller QDs designated
as QD 830 are green-emitting QDs and larger QDs designated as QD
840 are red-emitting QDs. The CED optionally includes a reflector
880 adjacent to a second surface 813 of light guide plate 810.
Reflector 880 may be attached to light guide plate 810 using an
optically clear adhesive (OCA); desirably one that has a refractive
index that is the same as, or nearly the same as, that of the light
guide plate.
[0078] As depicted in FIG. 9, CED 800 can include protective layer
826 deposited over the array of QD-containing structures 822.
Protective layer 826 can be a thick layer that encapsulates the
QD-containing layer. For example, protective layer 826 can be
between about 1 .mu.m to about 100 .mu.m in thickness. Protective
layer 826 can be a thick polymeric layer, such as polyethylene
terephthalate (PET), or an (meth)acrylate-based polymeric film. It
should be noted that when the protective layer is polymeric, it can
be deposited using inkjet printing, as exemplified by US Patent
Publication 2016/0024322.
[0079] An alternative embodiment of a CED having LEDS 812
illuminating its near end edge 815 is shown in FIG. 10. As
indicated by the use of like numerals, the components of this CED
can be the same as those shown in FIG. 9, but in this embodiment
the discontinuous QD-containing layer composed of QD-containing
structures 822 and protective layer 826 have been printed onto
second surface 813 of light guide plate 810, such that light
emitted through second surface 813 passes through QD-containing
structures 822 and protective layer 826, is reflected from
reflector 880, and passes back through QD-containing structures
822, protective layer 826, and light guide plate 810 before exiting
the CED through first surface 811. A similar geometry can be
achieved by printing QD-containing structures 822 and protective
layer 826B directly onto the surface of reflector 880 that faces
light guide plate 810, rather than onto second surface 813 of light
guide plate 810. After the protective layer has been printed on the
reflector, the reflector can be laminated onto the second surface
of the light guide plate.
[0080] In variations of the CEDs shown in FIGS. 8, 9, and 10 the
QD-containing structures can be uniformly spaced along the length
of the light guide plate, but the concentration of QDs in the
QD-containing structures can be tailored, such that the
concentration of QDs in the QD-containing structures increases as a
function of distance from the near end edge of the light guide
plate.
[0081] FIG. 11 illustrates a CED in which the outcoupling
functionality and color conversion functionality can be separated
into adjacent layers. In this embodiment, SNPs 870 are dispersed in
a discontinuous layer composed of a plurality of SNP-containing
structures 823. These structures provide the outcoupling
functionality of the device. Like QD-containing structures 822 in
FIG. 9, SNP-containing structures 823 are dome-shaped, although
they can have any arbitrary shape, and are distributed with a
density gradient along the length of light guide plate 810. In this
embodiment, QDs 830/840 are dispersed in the matrix of a continuous
QD-containing layer 836 providing the color conversion
functionality of the device. The effect of the SNP concentration
gradient in this embodiment, and in other embodiments, of the CED
is to improve the uniformity of the light intensity out-coupled
from light guide plate 810 into QD-containing layer 836 and,
ultimately, also the uniformity of the intensity of the light
exiting the CED.
[0082] In a variation of the CED shown in FIG. 11 the
SNP-containing structures can be uniformly spaced along the length
of the light guide plate, but the concentration of SNPs in the
SNP-containing structures can be tailored, such that the
concentration of SNPs in the SNP-containing structures increases as
a function of distance from the near end edge of the light guide
plate.
[0083] For simplicity, continuous QD-containing layer 836 is
depicted in this and other embodiments as containing QDs having the
same size. However, it should be understood that the
QD-containing-layers in the CEDs would include different types of
QDs, including green-emitting QDs, red-emitting QDs, blue-emitting
QDs, and combinations of two or more thereof.
[0084] FIG. 12 is provided to explicitly depict one example of a
CED that includes both GSNPs and PSNPs. Thus, unlike in the other
figures discussed herein, GSNPs and PSNPs are represented by
differently sized open circles. In particular, the larger open
circles in FIG. 12 are used to represent GSNPs, while the smaller
open circles are used to represent PSNPs. In the embodiment
depicted in FIG. 12, QD-containing layer 836 includes PSNPs 875
dispersed in its matrix and GSNPs 823 are included in a separate,
discontinuous layer.
[0085] FIG. 13 shows an embodiment of a CED in which the SNPs 870
are dispersed in a continuous SNP-containing layer 824 and the QDs
are dispersed in a separate, continuous QD-containing layer 837
overlying SNP-containing layer 824. In embodiments of the CEDs
where the scattering nanoparticles and the quantum dots are located
in separate layers, the intensity of the light outcoupled from the
layer containing the SNP has a uniform intensity distribution, even
when the light outcoupled from the light guide plate does not--as
in the case of a light guide plate that is illuminated by a light
source at its end edge. Because the light outcoupled from the layer
containing the SNPs has a uniform intensity along its length, the
QD-containing layer need not have a QD concentration gradient.
[0086] In the embodiment shown in FIG. 13, continuous
SNP-containing layer 824 has been printed directly onto first
surface 811 of light guide plate 810 and continuous QD-containing
layer 837 has been printed directly on continuous SNP-containing
layer 824. In this configuration, light emitted through first
surface 811 passes through SNP-containing layer 824 and scatters
from SNPs 870 to cause the out-coupling of the light to
QD-containing layer 837. In order to compensate for the higher
light intensity from near end edge 815 of light guide 810, there is
a gradient in the density of SNPs 870 along the length of
SNP-containing layer 824, whereby the density of the SNPs increases
as a function of distance from near end edge 815. To further
compensate for the non-uniform light intensity emitted from light
guide plate 810, SNP-containing layer 824 also has a variable
thickness along its length, whereby the thickness of the
SNP-containing layer increases as a function of distance from near
end edge 815. An alternative geometry can be achieved by printing
SNP-containing layer 824 directly onto second surface 813 of light
guide plate 810 and printing QD-containing layer 837 onto first
surface 811 of light guide plate 810; or by printing SNP-containing
layer 824 directly onto the surface of reflector 880 that faces
light guide plate 810 and printing QD-containing layer 837 onto
first surface 811 of light guide plate 810.
[0087] FIG. 14 shows a variation of the CED of FIG. 13 in which the
QDs 830/840 and the SNPs 870 are combined in a single layer, which
is referred to herein as a QD/SNP-containing layer 825. Like
SNP-containing layer 824 in the CED of FIG. 13, QD/SNP-containing
layer 825 has a gradient in the density of SNPs 870, as well as a
variable thickness, along its length. Also, like QD-containing
layer 837 in the CED of FIG. 13, QD/SNP-containing layer 825 has a
uniform QD concentration along its length. However, due to the
wedge-shaped profile of QD/SNP-containing layer 825, the surface
density of QDs 830/840 (that is--the density of QDs per mm.sup.2,
as viewed through the top surface of the layer) increases from near
end edge 817 to far end edge 818. An alternative geometry can be
achieved by printing QD/SNP-containing layer 825 directly onto
second surface 813 of light guide plate 810; or by printing
QD/SNP-containing layer 825 directly onto the surface of reflector
880 that faces light guide plate 810. This structure can be
achieved, for example, by simultaneously printing with two
different inks (a first ink containing the QDs and a second ink
containing the SNPs). Alternatively, a layer could be printed using
the first ink followed by a layer using the second ink, followed by
interdiffusion of these printed layers yield layer 825.
[0088] FIGS. 15 and 16 show variations of the CEDs of FIGS. 13 and
14, respectively, in which the SNP-containing layer 824 (in the
case of FIG. 15) and QD/SNP-containing layer 825 (in the case of
FIG. 16) have a uniform thickness along their lengths.
[0089] Although the concentration gradients for the QDs and/or the
SNPs in the CEDs of FIGS. 9-16 show a particle concentration that
increases linearly or substantially linearly from a near end edge
to a far end edge, other particle concentration patterns can be
used to provide a non-uniform particle concentration through all or
a portion of a printed layer. For example, the particle
concentration can increase exponentially across the layer or may
have a regular or irregular periodic variation across the layer. By
way of further illustration, the concentration of QDs and/or
scattering nanoparticles can increase from the far end edge of a
layer to the near end edge of the layer; from the top of a layer to
the bottom of the layer; from the bottom of a layer to the top of a
layer, or from a peripheral portion of the layer to the center of
the layer.
[0090] FIGS. 17, 18, 19, and 20 show variations of the CEDs of
FIGS. 9, 11, 15, and 16, respectively, in which light guide plate
810 is back lit, rather than edge lit. (It is noted again that,
although the device substrate is illustrated with a light guide
plate in these embodiments, other device substrate could be used,
including a diffuser or a polarizer.) In each of these CEDs, one or
more LEDs 812 illuminate light guide plate 810 through second
surface 813, rather than near end edge 815. In the back lit
devices, there is no edge-to-edge gradient in the intensity of
light emitted from light guide plate 810. Therefore, QD-containing
structures 822 and SNP-containing structures 823 may be uniformly
spaced along first surface 811 of light guide plate 810 in the CEDs
of FIGS. 17 and 18, and SNP-containing layer 824 and
QD/SNP-containing layer 825 may have a uniform density of SNPs 870
along their lengths in FIGS. 19 and 20. Although the QD-containing
structures 822 in the embodiments shown in FIGS. 17-20 include a
mixture of red light-emitting QDs 840 and green light-emitting QDs
830, the red light-emitting QDs 840 and the green light-emitting
QDs could also be separated in different QD-containing structures
822. LEDs 812 may be, for example, blue LEDs and QD-containing
structures 822 may include red light-emitting QDs and green
light-emitting QDs. When such a device is in operation, the blue
light emitted from blue LEDs 812 is absorbed by red light-emitting
QDs 840 and green light-emitting QDs 830, which convert at least a
portion of the blue light into red light and green light. The light
output from the device will be a mixture of the unconverted blue
light, the red light, and the green light. In some embodiments of
the device, the light output will be white light. An embodiment of
a device architecture that can be used to partially convert blue
light into a mixture of blue, red, and green light is described in
U.S. Pat. No. 8,330,348.
[0091] Although not shown here, other embodiments of the edge lit
CEDs could also be reconfigured as back lit CEDs, including the
embodiments depicted in FIGS. 9, 12, 13, and 14 and their
alternative geometries.
[0092] While there is no edge-to-edge gradient in the intensity of
the light emitted from surface 811 light guide plate 810 in the
back lit CEDs of FIGS. 17-20, the intensity of the light emitted
from light guide plate 810 can be non-uniform due to the placement
of LEDs 812, with a higher intensity of light entering the portions
of the light guide plate disposed directly above the LEDs and a
lower intensity of light entering the portions of the light guide
plate disposed between the LEDs. FIG. 21 shows an embodiment of a
CED that compensates for this intensity non-uniformity. As
illustrated in this figure, thicknesses of SNP-containing layer
824B and QD-containing layer 837C can be modulated along their
lengths.
[0093] A particle-containing layer in a CED can be printed as a
continuous layer having a QD concentration gradient, a GSNP
concentration gradient, a PSNP concentration gradient, or a
combination thereof, via the sequential or simultaneous inkjet
printing of three or more different ink compositions. Although the
layers depicted in FIGS. 8-16 as having a linear or substantially
linear QD and/or SNP concentration gradient along their lengths,
the layers can be printed with other gradient patterns, including
exponential gradients, as discussed above.
[0094] One embodiment of a method for inkjet printing a continuous
layer having a QD concentration gradient and/or a SNP concentration
gradient utilizes three inks. In some embodiments of these
multi-ink printing methods, the first ink composition contains the
QDs and a binder; the second ink composition contains the SNP and a
binder; and the third ink composition contains a binder, without
the QDs or the SNPs. Using this method, the concentration of
particles (QDs or SNPs) printed onto a given surface area will be
determined by the concentration of the QDs and SNPs in their
respective ink compositions and by the volume ratios of the three
ink compositions printed over that surface area. The volume of an
ink composition can be controlled by controlling the drops of the
ink composition printed per area ("DPA"). By way of illustration, a
first portion of a layer that is formed by printing the three ink
compositions in volumes that satisfy the relationship
(DPA).sub.binder>(DPA).sub.SNP>(DPA).sub.QD will have a lower
concentration of SNPs and QDs than another portion of the film
layer that is formed by printing the three ink compositions in
volume ratios that satisfy the relationship
(DPA).sub.QD>(DPA).sub.SNP>(DPA).sub.binder, provided that
the total number of drops per area
(DPA).sub.binder+(DPA).sub.SNP+(DPA).sub.QD remains constant.
[0095] The three ink compositions can be printed over the surface
of a substrate, such as a light guiding plate, a transparent
substrate, a diffuser, or a reflector, simultaneously,
sequentially, or a combination thereof. For example, two of the ink
compositions can be printed simultaneously and the third can be
printed subsequently. If the different ink compositions are
intended to form separate and distinct layers in the printed film,
the ink compositions can be printed sequentially and allowed to dry
or cure prior to the printing of a subsequent layer. Alternatively,
if the different ink compositions are intended to form a single
blended layer in which the binders and particles in the ink
compositions are intermixed, the ink compositions can be printed
simultaneously or sequentially. When different ink compositions are
printed sequentially and a blended layer is desired, the printing
should take place on a timescale that allows the ink compositions
to mix into a single layer before the ink compositions is dried or
cured into a film.
[0096] A method for inkjet printing a QD-containing layer on a
substrate surface is illustrated schematically in FIG. 22. The
method will be illustrated in the description that follows as a
method for inkjet printing a layer containing both QDs and SNPs on
a substrate surface, wherein the layer has a concentration gradient
in the and SNPs from one edge to the layer to the other. However,
the same equipment and general procedure also could be used to
print layers containing only QDs or only SNPs by varying the ink
compositions used and the order in which the ink compositions are
deposited. In addition, the ink compositions used to inkjet print
the various layers are described generally with reference to FIG.
22. A more detailed description of ink compositions that can be
used to form one of more layers in a CED is provided below.
[0097] As shown in panel (a) of FIG. 22, the inkjet printing
process can begin by printing a layer of material 2201 onto a
surface 2202 of a substrate 2203. As previously discussed, the
substrate can take the form of a variety of device substrates, such
as a light guide, a reflector, or a polarizer. In the embodiment
depicted here, three inkjet nozzles 2204A, 2204B, and 2204C, each
of which prints droplets of a different ink composition 2205A,
2205B, and 2205C, are used. By way of illustration, ink composition
2205A can contain curable polymer binder precursors, without any
QDs or SNPs. This ink composition acts as a diluent for the other
ink compositions during the printing of later 2201. Ink composition
2205B can contain curable polymer binder precursors and QDs and ink
composition 2205C can contain a curable polymer binder precursors
and SNPs. To form printed layer 2201, droplets of ink compositions
2205A, 2205B, and 2205C are jetted from nozzles 2204A, 2204B, and
2204C, respectively, either simultaneously or sequentially onto
surface 2202. As the printing progresses from a first edge 2206 to
a second edge 2207 of printed layer 2201, the relative volume
ratios of the three ink compositions are adjusted so that the
desired volumetric densities of the QD and SNP are achieved. For
example, the density of the SNPs is lowest at first edge 2206 and
higher at second edge 2206, while the volume density of QDs remains
constant from edge-to-edge. The polymer binder precursors, which
form the matrix of the cured layer after curing, can the same or
different for each ink composition. If the ink compositions are to
be printed successively and then allowed to mix to form a single
layer, the polymer binder precursors should be miscible. Once
printed, the layer can be cured by, for example, UV curing, thermal
curing, or a combination thereof. Although not shown here, if the
QDs and SNPs are inkjet printed as separate layers, the polymer
binder precursors can be the same. This may be advantageous for
devices in which the layers desirably have the same refractive
index.
[0098] Optionally, as shown in panel (b) of FIG. 22, a second layer
2210 can be printed over first printed layer 2201 using one of more
of inkjet nozzles 2204A, 2204B, and/or 2204C and this layer can
also undergo a post-deposition cure. Next a polymeric protective
layer 2211 that is free of QDs and SNPs can be formed over second
layer 2210 by inkjet printing an ink composition 2205D that
includes protective, curable polymer precursors over the second
layer and curing the ink composition (panel (c)). Once cured,
polymeric protective layer 2211 helps to protect first layer 2201
and second layer 2210 from exposure to damaging effects of the
atmosphere, such as water, oxygen, and/or ozone, and allows the CED
to be handled prior to incorporation into a larger device
structure. In addition, printed polymeric protective layer 2211 can
protect layers 2201 and 2210 from the damaging effects of
subsequent device processing steps, such as plasma enhanced
chemical vapor deposition (PECVD). For example, as shown in panel
(d), PECVD may be used to deposit an inorganic barrier layer 2212
over polymeric protective layer 2211. Inorganic barrier layer,
provides an enhanced degree of protection from the atmosphere. In
various embodiments, barrier layer 2212 can be a deposited dense
layer of an inorganic material, such as selected from classes of
inorganic materials including metal oxides, metal nitrides, metal
carbides, metal oxynitrides, metal oxyborides, and combinations
thereof. For example, but not limited by SiN.sub.x,
Al.sub.2O.sub.3, TiO.sub.2, HfO.sub.2, SiO.sub.xN.sub.y or
combinations thereof can be used for inorganic barrier layer 2212.
Alternatively, as shown in panel (e) a polymeric film 2213 can be
laminated directly onto polymeric protective layer 2211. (Polymeric
film 2213 could also be laminated directly onto inorganic barrier
layer 2212 in panel (d).) Laminated polymeric film 2213 can provide
an additional degree of protection and can permanently laminated to
the structure, such that it is ultimately incorporated into a final
device structure, or temporarily attached, such that it is removed
prior to the final device assembly. Panel (f) in FIG. 22
illustrates the temporary attachment of laminated polymeric film
2213 to the underlying structure, wherein a coating of optically
clear adhesive 2214 is disposed between printed polymeric
protective layer 2211 and laminated polymeric film 2213.
[0099] While the methods for printing film layers having particle
concentration gradients described herein and illustrated in FIG. 22
use at least three ink compositions, more than three ink
compositions or fewer ink compositions can be used. For example,
the printing methods can use two or more different QD-containing
ink compositions having different concentrations or types of the
quantum dots, or two or more different scattering
nanoparticle-containing ink compositions having different
concentrations or types of the scattering nanoparticles. For
example, in some embodiment of the printing methods, an ink
composition containing PSNPs and a binder can be used along with a
separate ink composition containing GSNPs and a binder.
Alternatively, only two ink compositions can be used. For example,
if a layer containing only one type of particles (e.g., only QDs,
only GSNPs, or only PSNPs) is being printed, the first ink
composition can contain the particles and a binder and the second
ink composition can contain a binder, without the particles. By
printing the two ink compositions simultaneously or sequentially
and varying the drops per area of the two ink compositions during
the printing process, as discussed above with respect to a
three-ink composition protocol, a layer having a particle gradient
along its length can be achieved. Alternatively, this concept also
provides for more than three inks. For example, several inks for
SNP with binder can be used where the SNP are PSNP of different
particle sizes.
[0100] For some applications, it can be advantageous to provide a
sealing layer around the perimeter of the CED or at least around
one or more layers of the CED. These sealing layers can be sealed
against another device layer to provide a water and/or oxygen proof
edge seal. CEDs fabricated with sealing layers can be cut to size
and sealed into a device without the risk of lateral ingress of
water and/or oxygen and subsequent damage to the CED. FIGS. 23 and
24 show schematic illustrations of a method for forming a CED
having a sealing layer. In this embodiment, the sealing layer
includes a plurality of sealing banks 2302 that are inkjet printed
onto a substrate 2304 using an ink composition 2306 that includes
curable sealing materials, such as curable monomers, oligomers,
polymers, or mixtures thereof, and, optionally, SNPs (FIG. 23, left
panel). In some embodiments of the sealing layers, sealing banks
2302 have SNPs dispersed therein. In these embodiments, the SNPs
can serve to help redirect light from a light source, such as a
back-lit unit, into a QD-containing layer printed between the
sealing banks (as described below). Like the QD- and SNP-containing
layers of the CED, described above, the SNPs within the sealing
banks or in different sealing banks can have a non-uniform (e.g.,
gradient) density distribution across the sealing layer in order to
provide the CED with more uniform light emission. Although sealing
banks 2302 in FIG. 23 are depicted as being inkjet printed, other
fabrication methods, such as nano-imprinting can be used to form
these banks.
[0101] Optionally, a barrier layer 2308 is formed over sealing
barriers 2302 and the exposed portions of substrate 2304 (FIG. 23,
right panel). This barrier layer, which can be, for example, an
inorganic material, such as by SiN.sub.x, Al.sub.2O.sub.3,
TiO.sub.2, ZnO, ZrO.sub.2, HfO.sub.2, SiO.sub.xN.sub.y or
combinations thereof, provides additional protection from water
and/or oxygen.
[0102] Once the barrier layer has been formed, one or more layers
of a CED 2310, including QD-containing layers and/or SNP-containing
layers, can be inkjet printed into the recesses 2312 defined
between sealing banks 2302, as shown in FIG. 24 (left panel). A
temporary or permanent film 2314 can then be sealed to sealing
banks 2302 to cover and protect the CED layers 1910 (FIG. 24, right
panel).
[0103] It should be noted that, while the formation of various
device layers is described herein as including a curing step,
device layers formed from non-curable compositions may be formed
simply by drying.
Curable Ink Compositions
[0104] The following teachings relate to various embodiments of ink
compositions which, once printed and dried and/or cured, form thin
polymeric layers, including, but not limited to, the local light
filter layers, the global light filter layers, the light-emitting
layers, the light-scattering layers, and/or the color enhancement
layers described herein. Various embodiments of the ink
compositions can be printed using, for example, an industrial
inkjet printing system that can be housed in a gas enclosure, which
gas enclosure defines an interior that has a controlled environment
maintained as an inert and substantially low-particle process
environment. QD-containing light-emitting layers can be inkjet
printed over various previously formed device substrates, such as a
light polarizer or a local light filter layer of the type disclosed
herein, and then cured using, for example, a thermal or UV cure. By
way of non-limiting example, a light source, such as a solid-state
LED, emitting at a nominal wavelength in the range from 350 nm to
395 nm at a radiant energy density of up to 2.0 J/cm.sup.2 could be
used to cure a curable ink composition.
[0105] The compositions described herein are referred to as "ink
compositions" because various embodiments of the compositions can
be applied using techniques, including printing techniques, by
which conventional inks have been applied to substrates. Such
printing techniques include, for example, inkjet printing, screen
printing, thermal transfer printing, flexographic printing, and/or
offset printing. However, various embodiments of the ink
compositions can also be applied using other coating techniques,
such as, for example, spray coating, spin coating, and the like.
Moreover, the ink compositions need not contain colorants, such as
dyes and pigments, which are present in some conventional ink
compositions.
[0106] It is contemplated that a wide variety of ink compositions
can be printed. By way of illustration, during the manufacture of
an LCD device, an LCD sub-pixel can be formed to include the
various device layers described herein. Various ink compositions
for a sub-pixel can be inkjet printed using ink compositions
tailored for the formation of an absorbing dye-containing layer, a
QD-containing layer for a red sub-pixel, a green sub-pixel, or a
blue sub-pixel, a scattering nanoparticle-containing layer, or a
QD-free polymer matrix layer for a blue sub-pixel, as well as a
polymeric planarization layer.
[0107] The curable ink compositions include one or more polymer
binder precursors, such as monomers and oligomers, that are
polymerizable and form a polymer upon curing. As such, ink
compositions that include the polymer binder precursors are
polymer-forming ink compositions.
[0108] Various embodiments of the ink compositions include: one or
more mono(meth)acrylate monomers, one or more di(meth)acrylate
monomers, or a combination of one or more mono(meth)acrylate
monomers with one or more di(meth)acrylate monomers; one or more
multifunctional crosslinking agents; optionally, one or more
polymerizable diluents; and quantum dots that are
surface-functionalized with organic ligands. As used herein, the
phrase "(meth)acrylate monomer" indicates that the recited monomer
may be an acrylate or a methacrylate.
[0109] Various embodiments of the ink compositions have a
(meth)acrylate monomer content in the range from about 30 wt. % to
about 96 wt. %. This includes embodiments of the ink compositions
having a (meth)acrylate monomer content in the range from about 50
wt. % to 95 wt. %, further includes embodiments of the ink
compositions having a (meth)acrylate monomer content in the range
from about 70 wt. % to 90 wt. %, still further includes embodiments
of the ink compositions having a (meth)acrylate monomer content in
the range from 65 wt. % to 75 wt. %, and still further includes
embodiments of the ink compositions having a (meth)acrylate monomer
content in the range from 65 wt. % to 70 wt. %. Some embodiments of
the ink composition include only a single (meth)acrylate monomer,
while others include a mixture of two or more (meth)acrylates. For
example, various embodiments of the ink compositions include two
mono(meth)acrylate monomers, two di(meth)acrylate monomers, or a
mono(meth)acrylate monomer in combination with a di(meth)acrylate
monomer. Some embodiments of the ink compositions are free of
di(meth)acrylates and some embodiments of the ink composition are
free of (mono)methacrylates. The weight ratios of the two
(meth)acrylate monomers can vary significantly in order to tailor
the viscosity, surface tension, and film-forming properties of the
ink compositions. By way of illustration, some embodiments of the
ink compositions that include two of the mono- or di(meth)acrylate
monomers include a first mono(meth)acrylate or di(meth)acrylate
monomer and a second mono(meth)acrylate or di(meth)acrylate monomer
in a weight ratio in the range from 95:1 to 1:2, including in a
weight ratio range from 12:5 to 1:2. This includes embodiments of
the ink compositions in which the weight ratio of the first
mono(meth)acrylate or di(meth)acrylate monomer to the second
mono(meth)acrylate or di(meth)acrylate monomer is in the range from
12:5 to 4:5; further includes embodiments of the ink compositions
in which the weight ratio of the first mono(meth)acrylate or
di(meth)acrylate monomer to the second mono(meth)acrylate or
di(meth)acrylate monomer is in the range from 5:4 to 1:2; and still
further includes embodiments of the ink compositions in which the
weight ratio of the first mono(meth)acrylate or di(meth)acrylate
monomer to the second mono(meth)acrylate or di(meth)acrylate
monomer is in the range from 5:1 to 5:4.
[0110] Some embodiments of the ink compositions have an organic
ligand-capped QD concentration in the range from about 0.1 wt. % to
about 50 wt. %, including concentrations in the range from about 1
wt. % to about 50 wt. %, in the range from about 20 wt. % to 30 wt.
%, and in the range from about 5 wt. % to about 20 wt. %--although
concentrations outside of these ranges can be employed.
[0111] Some embodiments of the ink compositions are free of
crosslinking agents, while others include one or more crosslinking
agents. In some embodiments of the ink compositions,
multifunctional (meth)acrylate crosslinking agents can account for
between about 3 wt. % to about 10 wt. % of the ink composition.
This includes ink compositions having a multifunctional
(meth)acrylate crosslinking agent content in the range from 4 wt. %
to 6 wt. %.
[0112] In some embodiments of the ink compositions, photoinitiators
will be included in amounts in the range from about 0.1 wt. % to
about 10 wt. %, including amounts in the range from about 0.1 wt. %
to about 8 wt. %. This includes embodiments in which the
photoinitiators are present in amounts in the range from about 1
wt. % to about 6 wt. %, further includes embodiments in which the
photoinitiators are present in amounts in the range from about 3
wt. % to about 6 wt. %, and still further includes embodiments in
which the photoinitiators are present in amounts in the range from
about 3.75 wt. % to about 4.25 wt. %.
[0113] The mono(meth)acrylate and di(meth)acrylate monomers are
ether and/or ester compounds that have thin film-forming properties
and spreading properties that render them suitable for use
film-forming applications, such as in inkjet printing applications.
As components of various embodiments of the ink compositions, these
monomers can provide compositions that are jettable at a range of
inkjet printing temperatures, including room temperature.
Generally, for ink compositions useful for inkjet printing
applications, the surface tension, viscosity and wetting properties
of the ink compositions should be tailored to allow the
compositions to be dispensed through an inkjet printing nozzle
without drying onto or clogging the nozzle at the temperature used
for printing (e.g., room temperature, .about.22.degree. C., or at
higher temperatures up to, for example, about 40.degree. C.). Once
formulated, various embodiments of the ink compositions can have a
viscosity of, for example, between about 2 cps and about 30 cps,
including, for example, between about 5 cP and 12 cP, between about
10 cps and about 27 cps, or between about 14 cps and about 25 cps,
at 22.degree. C. and a surface tension of between about 25 dynes/cm
and about 45 dynes/cm, including, for example, between about 30
dynes/cm and about 42 dynes/cm, and between about 28 dynes/cm and
about 38 dynes/cm at 22.degree. C.
[0114] The suitable viscosities and surface tensions for the
individual monomers used in the ink compositions will depend on the
viscosities and surface tensions for the other components present
in a given ink composition and on the relative amounts of each
component in the ink composition. Generally, however, the
mono(meth)acrylate monomers and the di(meth)acrylate monomers will
have a viscosity in the range from about 1 cps to about 22 cps at
22.degree. C., including about 4 cps to about 18 cps at 22.degree.
C., and a surface tension in the range from about 30 dynes/cm to 41
dynes/cm at 22.degree. C., including in the range from about 32
dynes/cm to 41 dynes/cm at 22.degree. C. Methods for measuring
viscosities and surface tensions are well known and include the use
of commercially available rheometers (e.g., a DV-I Prime Brookfield
rheometer) and tensiometers (e.g., a SITA bubble pressure
tensiometer).
[0115] The mono(meth)acrylate monomers and di(meth)acrylate
monomers can be, for example, linear aliphatic mono(meth)acrylates
and di(meth)acrylates, or can include cyclic and/or aromatic
groups. In various embodiments of the inkjet printable ink
compositions, the mono(meth)acrylate monomers and/or
di(meth)acrylate monomers are polyethers. In various embodiments of
the inkjet printable ink compositions, the (meth)acrylate monomers
are glycol ether (meth)acrylate monomers. These include ethylene
glycol phenyl (meth)acrylate (EGPE(M)A), di(ethylene glycol) methyl
ether (meth)acrylate (DEGME(M)A), diethylene glycol monoethyl ether
acrylate, ethylene glycol methyl ether (meth)acrylate (EGME(M)A),
1,3-butylene glycol di(meth)acrylate, and polyethylene glycol
di(meth)acrylate. The polyethylene glycol di(meth)acrylate
monomers, including polyethylene glycol di(meth)acrylate monomers
having a number average molecular weight in the range from, for
example, about 230 g/mole to about 440 g/mole. For example, the ink
compositions can include polyethylene glycol 200 dimethacrylate
and/or polyethylene glycol 200 diacrylate, having a number average
molecular weight of about 330 g/mole.
[0116] Other suitable (meth)acrylate monomers include, but are not
limited to: alkyl (meth)acrylates, such as methyl (meth)acrylate
and ethyl (meth)acrylate; cyclic (meth)acrylates, such as
tetrahydrofurfuryl methacrylate, alkoxylated tetrahydrofurfuryl
(meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate;
and aromatic (meth)acrylates, such as benzyl (meth)acrylate and
phenoxyalkyl (meth)acrylates, including 2-phenoxyethyl
(meth)acrylate and phenoxymethyl (meth)acrylate.
[0117] The (meth)acrylate monomers can also be, for example,
alkoxylated aliphatic di(meth)acrylate monomers. These include
1,6-hexanediol diacrylate and neopentyl glycol group-containing
di(meth)acrylates, including alkoxylated neopentyl glycol
diacrylates, such as neopentyl glycol propoxylate di(meth)acrylate
and neopentyl glycol ethoxylate di(meth)acrylate. Various
embodiments of the neopentyl glycol group-containing
di(meth)acrylates have molecular weights in the range from about
200 g/mole to about 400 g/mole. This includes neopentyl
glycol-containing di(meth)acrylates having molecular weights in the
range from about 280 g/mole to about 350 g/mole and further
includes neopentyl glycol-containing di(meth)acrylates having
molecular weights in the range from about 300 g/mole to about 330
g/mole. Various neopentyl glycol group-containing di(meth)acrylate
monomers are commercially available. For example, neopentyl glycol
propoxylate diacrylate can be purchased from Sartomer Corporation
under the tradename SR9003B and also from Sigma Aldrich Corporation
under the tradename Aldrich-412147 (.about.330 g/mole; viscosity
.about.18 cps at 24.degree. C.; surface tension .about.34 dynes/cm
at 24.degree. C.). Neopentyl glycol diacrylate also can be
purchased from Sigma Aldrich Corporation under the tradename
Aldrich-408255 (.about.212 g/mole; viscosity .about.7 cps; surface
tension .about.33 dynes/cm).
[0118] Still other mono- and di(meth)acrylate monomers that can be
included in various embodiments of the ink compositions, alone or
in combination, include dicyclopentenyloxyethyl acrylate (DCPOEA),
isobornyl acrylate (ISOBA), dicyclopentenyloxyethyl methacrylate
(DCPOEMA), isobornyl methacrylate (ISOBMA), and N-octadecyl
methacrylate (OctaM). Homologs of ISOBA and ISOBMA (collectively
"ISOB(M)A" homologs) in which one or more of the methyl groups on
the ring is replaced by hydrogen can also be used.
[0119] The multifunctional (meth)acrylate crosslinking agents
desirably have at least three reactive (meth)acrylate groups and
may have at least four reactive (meth)acrylate groups. Thus, the
multifunctional (meth)acrylate crosslinking agents can be, for
example, tri(meth)acrylates, tetra(meth)acrylates and/or higher
functionality (meth)acrylates. Pentaerythritol tetraacrylate,
pentaerythritol tetramethacrylate, di(trimethylolpropane)
tetraacrylate and di(trimethylolpropane) tetramethacrylate are
examples of multifunctional (meth)acrylates that can be used as a
primary cross-linking agent. The term `primary` is used here to
indicate that other components of the ink compositions may also
participate in crosslinking, although that is not their main
functional purpose.
[0120] The polymerizable diluents are organic compounds that
enhance the solubility of the organic ligand-capped QDs in the
(meth)acrylate-based ink compositions. The diluents are relatively
low viscosity compounds that are able to participate in
free-radical polymerization processing during the curing of the ink
compositions and, as such, are able to become covalently bound into
the resulting polymeric film. However, the reactivity of the
diluents is desirably low enough to avoid premature polymerization
prior to the initiation of the cure. For this reason, in some
embodiments of the ink compositions, the polymerizable diluents are
not (meth)acrylates. The low viscosity compounds may have
viscosities in the range of, for example, 1 cP to 5 cP. Examples of
suitable polymerizable diluents include compounds having a
crosslinkable maleimide group or a crosslinkable norbornene group.
In addition to a polymerizable group, the diluent compounds include
a chain group, such as a polyether chain. The polyether chain can
include, for example, a polypropylene oxide chain, a polyethylene
oxide chain, or a polyether chain that includes both polypropylene
oxide groups and polyethylene oxide groups along its backbone.
Maleimide compounds having hydrophilic polyether groups can be
synthesized from a primary polyether amine and
exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, as illustrated
in Example 5. Polyether amines are sold commercially by Huntsman
under the tradename Jeffamine.RTM.. Some embodiments of these
polyether amines have the general structure:
##STR00001##
where R.dbd.H for ethylene oxides, R.dbd.CH.sub.3 for propylene
oxides, and x and y represent the number of repeat units along the
backbone chain. In some embodiments of the values of x and y are in
the range from 1 to 12, including in the range from 1 to 10. By way
of illustration, Jeffamine.RTM. M-600 comprises polyether amines
having the general structure:
##STR00002##
In some embodiments, mixtures of two or more different polyether
amines, including two or more of the Jeffamine.RTM. amines shown
above, can be used. Norbornyl compounds having polyether groups can
be synthesized through the reaction of any acrylate or methacrylate
with cyclopentadiene. The polyether groups of the diluents can be,
but need not be, the same group as the spacer chains of the
hydrophilic ligands capping the QDs, which are described in greater
detail below. Embodiments of the ink compositions containing
diluents may have a diluents content of, for example, about 1 wt. %
to about 10 wt. %--although diluents contents outside of this range
can be used.
[0121] Photoinitiators can also, optionally, be included in the ink
compositions for photoinitiating the polymerization process. The
specific photoinitiators used for a given ink composition are
desirably selected such that they are activated at wavelengths that
are not damaging to materials used in the fabrication of the
device, such as materials used in the fabrication of LCD display
devices. The photoinitiators can be selected such that initial
polymerization is induced at wavelengths in the UV region of the
electromagnetic spectrum, the blue region of the visible spectrum,
or both. An acylphosphine oxide photoinitiator can be used, though
it is to be understood that a wide variety of photoinitiators can
be used. For example, but not limited by, photoinitiators from the
.alpha.-hydroxyketone, phenylglyoxylate, and .alpha.-aminoketone
classes of photoinitiators can also be considered. For initiating a
free-radical based polymerization, various classes of
photoinitiators can have an absorption profile of between about 200
nm to about 400 nm. For various embodiments of the ink compositions
and methods of printing disclosed herein,
2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) and
2,4,6-trimethylbenzoyl-diphenyl phosphinate have desirable
properties. Examples of acylphosphine photoinitiators include
Irgacure.RTM. TPO (also previously available under the tradename
Lucirin.RTM. TPO) initiators for UV curing sold under the
tradenames Irgacure.RTM. TPO, a type I hemolytic initiator which;
with absorption @ 380 nm; Irgacure.RTM. TPO-L, a type I
photoinitiator that absorbs at 380 nm; and Irgacure.RTM. 819 with
absorption at 370 nm. By way of illustration, a light source
emitting at a nominal wavelength in the range from 350 nm to 395 nm
at a radiant energy density of up to 1.5 J/cm.sup.2 could be used
to cure an ink composition comprising a TPO photoinitiator. Using
the appropriate energy sources, high levels of curing can be
achieved. For example, some embodiments of the cured films have a
degree of curing of 90% or greater, as measured by Fourier
Transform Infrared (FTIR) spectroscopy.
[0122] The QDs chosen for a given ink composition will depend on
the desired light-converting properties of the films made from the
ink compositions. By way of illustration only, QDs that can be
included in the ink compositions include InP QDs, ZnS QDs, ZnSe
QDs, and cadmium-containing QDs.
[0123] The QDs in the ink compositions include a surface film of
organic ligands. These organic ligands, which help to solubilize
the QDs and stabilize them against agglomeration in the
(meth)acrylate monomer-based ink compositions, include hydrophobic
hydrocarbon ligands; or hydrophilic ligands like ester ligands,
ether ligands, amine ligands, or a combination of two of more of
ester ligands, ether ligands, and amine ligands. In some
embodiments, the organic ligands are polyether amines and/or
polyester amines. The ligands each have at least one functional
group (a "head group"), which binds the ligand to the surface of a
QD, a backbone chain, and at least one tail group. The backbone
chain (also referred to as a spacer chain) separates the head group
from the tail group and may be, for example, 16-45 (including the
16-40) atoms (for example, carbon atoms, oxygen atoms, nitrogen
atoms, and/or sulfur atoms) long. However, ligands having shorter
or longer backbone chains can also be used. The organic ligands
bond to the QDs, typically via electrostatic interactions between
the head group and the QD surface and, in some embodiments, also
covalently crosslink to the monomer components in the ink
composition as it cures via their tail groups.
[0124] The organic ligands include monodentate ligands having a
single head group that binds to the surface of a QD and polydentate
ligands having two or more head groups that bind to the surface of
a QD. The polydentate ligands can be, for example, bidentate,
tridentate, tetradentate, or higher dentate ligands. Suitable head
groups include carboxylic acids, which bind to the surface of a QD
via a carboxylic acidic or a carboxylate group, as well as thiols
and/or amines. For example, ligands containing carboxyl (--COOH),
amine (--NR.sub.2, where R is an H atom or an alkyl group), and
thiol (--SH) groups have strong binding affinities for QDs surfaces
composed of Group II-VI elements.
[0125] By way of illustration, in some embodiments of the ink
compositions, the organic ligands have the following structure:
##STR00003##
where n represents the number of repeat units in the chain. In some
embodiments, n has a value between 4 and 12.
[0126] The crosslinkable ligands are characterized in that they
have a functional tail group with polymerizable bond, such as a
double bond, and at least one functional head group which undergoes
binding with the surface of a QD in the ink composition. Such
bi-functionality of the crosslinkable ligands keeps the QDs
dispersed in the curable ink compositions, and prevents their
re-aggregation during the curing process. In some embodiments, the
ligand has a tail group that is able to crosslink with the
(meth)acrylate monomers, the (meth)acrylate crosslinking agents,
and/or other ligands in the ink composition to provide a cured film
in which the QDs are stabilized throughout a crosslinked polymer
matrix. Crosslinkable tail groups include, but are not limited to,
acrylate groups, methacrylate groups, maleimide groups, norbornenyl
groups, allyl groups, and alkylbenzyl groups, such as styrene
groups.
[0127] In some embodiments of the ink compositions, the QDs are
functionalized with ligands having tail groups that do no crosslink
with other components in the cured composition. Examples of
non-crosslinkable ligands include ligands having alkylene oxide
tail groups, such as ethylene oxide tail groups and/or propylene
oxide tail groups, and ligands having carboxylic acid tail groups.
For the non-crosslinkable ligands, the tail group may be the
terminal group of the spacer chain.
[0128] Some embodiments of the ligands have two or more tail
groups. For example, various embodiments of the ligands have two
maleimide tail groups or two (meth)acrylate tail groups.
[0129] The spacer chain that connects the head group (or head
groups) of a ligand to its tail group (or tail groups) can be
comprised of, for example, unsaturated or saturated hydrocarbon
chain (hydrophobic fragments), or hydrophilic fragments such as a
short, oligo- and polymeric chain of ether, -ester, amine, amide
(e.g., a polyamide) chemical nature, or a combination of two or
more of these types of chains. For example, the spacers can include
one or more of the following structures along their chain:
##STR00004##
Where R=H, Me and/or Et
##STR00005##
where n represents the number of repeat units of the functional
group in the chain. By way of illustration, n may be up to 10, up
to 20, or higher. Thus, the number of repeat units can be 1, 2, 3,
4, 5, 6, or more. Various embodiments of these structures can
include different numbers of methylene groups in their repeating
functional groups. Thus, m represents the number of methylene
groups in structures. By way of illustration, in various
embodiments, m has a value in the range from 1 to 10. The spacer
chain can be an unbranched or a branched structure. If a ligand is
a multidentate ligand and/or if a ligand has two or more tail
groups, the spacer chain will be branched structure.
[0130] Some illustrative examples of hydrophilic ligands are
described in the Examples. One example of a monodentate carboxylic
acid ligand having a methacrylate tail group and one carboxylic
acid head groups is shown in FIG. 25. One example of a bidentate
dicarboxylic acid ligand having a methacrylate tail group and two
carboxylic acid head groups is shown in FIG. 26. In the structures,
n is an integer representing the number of repeat units in the
backbone chain. A synthesis scheme is also shown in the figure.
FIG. 27 shows the structure of another example of a bidentate
dicarboxylic acid ligand having a thioester tail group and two
carboxylic acid head groups, along with its synthesis scheme.
[0131] One example of a bidentate ligand having a maleimide tail
group and two carboxylic acid head groups is shown in FIG. 28. FIG.
29 shows the structures of four maleimide amines that can be used
to convert the (meth)acrylate tail group of an organic ligand into
a maleimide tail group. FIG. 30 illustrates a reaction scheme that
can be used to convert the (meth)acrylate tail group into a
maleimide tail group using a maleimide amine of the type shown in
FIG. 29, using the ligand shown in FIG. 26 as an example. The
product ligand shown here has a maleimide tail group and two
carboxylic acid head groups. FIG. 31 depicts a reaction scheme that
can be used to convert the ligand of the type shown in FIG. 27 into
a dicarboxylic ligand having a maleimide tail group. As shown in
the figure n can have a value of 1, 3, or 7. However, the ligand
can also have other n values. More details regarding the synthesis
of the organic ligands shown in FIGS. 26-31 are provided in the
Examples.
[0132] FIG. 32 illustrates how the use of ligands having
crosslinkable tail groups can stabilize QDs in a cured thin film.
The left panel in the figure is a schematic illustration of a QD
(represented in this embodiment as a core-shell QD with a ZnS
shell) initially capped with native hydrophobic ligands. The middle
panel shows the same QD, after the hydrophobic ligands have been
exchanged with hydrophilic ligands having maleimide tail groups, in
an ink composition that includes (meth)acrylate monomers
(represented in this embodiment by ethyl acrylate monomers). The
right panel is a schematic illustration of a cured film formed from
the ink composition, in which the maleimide tail groups have
crosslinked with the (meth)acrylate monomers to form an extended
polymer matrix into which the QDs are covalently bonded and
stabilized.
[0133] For purposes of illustration, the structures of some
non-crosslinkable ligands are shown in FIG. 33. These include
monodentate carboxylic acid ligands having alkyl oxide tail groups
(panels (a) and (b)), bidentate carboxylic acid ligands having
alkyl oxide tail groups (panels (c) and (d)), and a dicarboxylic
acid ligand (panel (e)). More details regarding the synthesis of
the organic ligands shown in FIG. 32 are provided in the
Examples.
[0134] In at least some embodiments the diluents render the
hydrophilic ligand-capped QDs soluble in (meth)acrylate-based ink
compositions in which they would otherwise be less soluble, or only
poorly soluble. As a result, the diluents enable the formulation of
ink compositions having higher QD concentrations that would be
possible in the absence of the diluents. By way of illustration,
various embodiments of the ink compositions have a QD concentration
of at least 5 wt. %, at least 10 wt. %, at least 15 wt. %, at least
20 wt. %, at least 25 wt. %, or at least 25 wt. %. For example, the
ink compositions can have a QD concentration in the ranges from
about 5 wt. % to about 80 wt. %. Without intending to be bound to
any one theory of the invention, the effect of the diluents may be
explained by a QD stabilizing effect brought on by the interaction
of the hydrophilic groups of the diluents with the hydrophilic
spacer chains of the ligands capping the QDs compounds and the
interaction of the polymerizable groups of the diluents with the
surrounding (meth)acrylate monomers. This is illustrated
schematically in FIG. 34.
[0135] A general description of embodiments of methods that can be
used to carry out ligand syntheses, ligand exchanges, and ink
formulation is provided below. The Examples that follow provide
more detailed guidance.
[0136] The QDs may initially include a surface film of capping
ligands. These capping ligands, which help to passivate the QDs and
stabilize them against agglomeration in solution, are frequently
present as a result of the solution phase growth of the QDs. The
capping ligands are typically hydrophobic organic ligands, such as
oleic acid, oleyl amine, and/or stearic acid. The capping ligands
can be replaced by the hydrophilic ligands via a ligand exchange
process. In such a process, the hydrophobic ligand-capped QDs are
introduced into a solution containing the hydrophilic ligands under
conditions (e.g., at concentrations and temperatures and for times)
that facilitate the exchange of the ligands on the QDs. Suitable
ligand exchange solvents include ethyl acetate, dimethoxy ethane
(DME), toluene, dimethylformamide (DMF), acetonitrile,
N-Methyl-2-pyrrolidone (NMP), and the like. The hydrophilic
ligand-capped QDs then can be washed and concentrated by dissolving
them in a wash solution. The washing and concentration steps can be
carried out multiple times. The dissolved hydrophilic ligand-capped
QD solution may then be mixed with a non-polar organic solvent,
such as toluene or hexane, whereby the hydrophilic ligand-capped
QDs precipitate out of solution. The precipitated QDs are then
separated from the solution using, for example, centrifugation
and/or filtration followed by drying under vacuum. The separated
hydrophilic ligand-capped QDs can then be redissolved in a polar
organic solvent and purified by, for example, a molecular weight
cut off (MWCO) centrifugal filter. Alternatively, a tangential flow
filtration (TFF) can be used to concentrate the hydrophilic
ligand-capped QDs. Tangential flow filtration systems are available
commercially from companies such as the Pall Corporation. Methods
of capping QDs with hydrophilic ligands and washing and
concentrating the hydrophilic ligand-capped QDs are illustrated in
the Examples.
[0137] The ligand exchange mechanism is illustrated schematically
in FIG. 35, where a QD (represented by a circle) is initially
capped with hydrophobic ligands (left panel). In this illustration,
the hydrophobic ligands are composed of a hydrocarbon chain with an
"X" group and the hydrophilic ligand are composed of a hydrocarbon
chain with a "Y" group. The ligand exchange reaction is a
reversible reaction that is driven by heat to equilibrium. It
occurs through a dissociative mechanism, by which the hydrophobic
ligand on the surface of the QD needs to open a coordination site
by dissociating a ligand from the QD surface before the hydrophilic
ligand is able to bind to the QD surface. In the case where both
ligands have the same binding constant, this reversible reaction
may be driven toward products (to the right) by adding an excess of
the hydrophilic ligand to the reaction solution. Alternatively,
this reversible reaction may also be driven toward products by
using ligands that have a higher binding constant than the ligands
on the QDs, such as when the hydrophilic ligand has a higher
bonding constant than the hydrophobic ligand. Because multidentate
ligands, such as bidentate ligands, bind to the surface more
effectively than monodentate ligands, they can assist with pushing
the equilibrium of the mechanism shown in FIG. 34 to the right. The
dissociation of ligands can be promoted by heating the solution for
a time sufficient for equilibrium to be achieved between the
`bound` ligands on the surface and `free` ligands in solution.
[0138] Once the hydrophilic ligand-capped QDs have been washed,
concentrated and separated, the QD concentrate can be re-dissolved
in a relatively polar organic solvent, such as ethanol, and
polymerizable diluent can be added to the solution. Volatile
compounds can then be removed to concentrate the hydrophilic
ligand-capped QDs in the diluents and this concentrate can then be
mixed with the (meth)acrylate monomers, crosslinking agent, and,
optionally, photoinitiator to provide an ink composition.
[0139] Given that the initiation of polymerization can be induced
by light, ink compositions can be prepared under conditions
preventing exposure to light. With respect to preparation of
organic thin layer ink compositions of the present teachings, in
order to ensure the stability of various compositions, the
compositions can be prepared in a dark or very dimly lit room or in
a facility in which the lighting is controlled to exclude
wavelengths that would induce polymerization. Such wavelengths
generally include those below about 500 nm.
[0140] The ink compositions can be inkjet printed using a printing
system, such as that described in U.S. Pat. No. 8,714,719, which is
incorporated herein in its entirety. The films can be cured in an
inert nitrogen environment using UV radiation. The ink compositions
can be designed to be applied by inkjet printing. Such ink
compositions are, therefore, characterized by jettability, wherein
a jettable ink composition displays constant, or substantially
constant, drop velocities, drop volumes and drop trajectories over
time when jetted continuously through the nozzle of a printhead. In
addition, such ink compositions are desirably characterized by good
latency properties, where latency refers to the time that nozzles
can be left uncovered and idle before there is a significant
reduction in performance, such as a reduction in drop velocity or
volume and/or a change in trajectory that will noticeably affect
the image quality.
[0141] Various embodiments of ink compositions, method of inkjet
printing and forming films from the ink compositions, and photonic
devices incorporating the films are presented below. However, the
inventions described herein are not limited to these illustrative
examples.
[0142] Various embodiments of the ink compositions include:
di(meth)acrylate monomers, mono(meth)acrylate monomers, or a
combination of di(meth)acrylate monomers and mono(meth)acrylate
monomers; optionally, a diluent comprising a polyether group and a
crosslinkable group; optionally, a multifunctional (meth)acrylate
crosslinking agent comprising at least three acrylate
functionalities; and quantum dots with organic ligands bound to
their surfaces. In some embodiments, the ink compositions include:
30 wt. % to 96 wt. % of the di(meth)acrylate monomers, the
mono(meth)acrylate monomers, or the combination of di(meth)acrylate
monomers and mono(meth)acrylate monomers; 1 wt. % to 10 wt. % of
the diluent comprising a polyether group and a crosslinkable group;
3 wt. % to 10 wt. % of the multifunctional (meth)acrylate
crosslinking agent; and 0.1 wt. % to 50 wt. % of the quantum dots
with the ligands bound to their surfaces. In some embodiments, the
ink compositions have a viscosity in the range from 2 cps to 30 cps
and a surface tension at 22.degree. C. in the range from 25 dyne/cm
to 45 dyne/cm at a temperature in the range from 22.degree. C. to
40.degree. C. In some embodiments of the ink compositions, the
di(meth)acrylate monomers, the mono(meth)acrylate monomers, or the
combination of di(meth)acrylate monomers and mono(meth)acrylate
monomers comprises a glycol ether (meth)acrylate monomer, a
tetrahydrofurfuryl (meth)acrylate monomer, or a combination
thereof. In some embodiment of the ink compositions, the ligands
are hydrophilic ligands. In some embodiments, the hydrophilic
ligands include ester ligands, ether ligands, or a combination of
ester ligands and ether ligands. In some embodiments, the
hydrophilic ligands comprise polydentate ligands having two or more
head groups bound to the surface of a quantum dot. In some
embodiments, the polydentate ligands are bidentate ligands having
two head groups bound to the surface of a quantum dot. In some
embodiments, the head groups include carboxylate groups. In some
embodiments, the ligands include ligand backbone chains, the ligand
backbone chains having from 16 to 24 carbon atoms. In some
embodiments, ligands are the hydrophilic ligands that include tail
groups that are crosslinkable with the di(meth)acrylate monomers,
the mono(meth)acrylate monomers, or the combination of
di(meth)acrylate monomers and mono(meth)acrylate monomers. In some
embodiments, the tail groups include maleimide groups. In some
embodiments, the tail groups include acrylate groups. In some
embodiments, the tail groups include methacrylate groups. In some
embodiments, the tail groups include styrene groups. In some
embodiments, the ligands are hydrophilic ligands having tail groups
comprising alkylene oxide groups. In some embodiments, the alkylene
oxide groups include ethylene oxide groups or propylene oxide
groups. In some embodiments, the crosslinkable group of the diluent
includes a maleimide group, a norbornene group, or a combination
thereof.
[0143] Various embodiments of the ink compositions include: 80 wt.
% to 97 wt. % di(meth)acrylate monomers, mono(meth)acrylate
monomers, or a combination of di(meth)acrylate monomers and
mono(meth)acrylate monomers; 3 wt. % to 10 wt. % multifunctional
(meth)acrylate crosslinking agent comprising at least three
acrylate functionalities; and 0.1 wt. % to 10 wt. % cure initiator.
In some embodiments of the ink compositions, the mono(meth)acrylate
monomers or the combination of di(meth)acrylate monomers and
mono(meth)acrylate monomers include benzyl methacrylate.
[0144] One embodiment of a method of forming a quantum
dot-containing film on a device substrate includes the steps of:
inkjet printing a layer of an embodiment of an ink composition as
disclosed herein on the surface of a device substrate; and curing
the curable ink composition.
[0145] Various embodiments of cured films include the
polymerization product of an embodiment of an ink composition as
disclosed herein.
[0146] Various embodiments of photonic devices include: a photonic
device substrate; and the polymerization product of an embodiment
of an ink composition as disclosed herein on the photonic device
substrate. In some embodiments, the device substrate is a light
guide plate and the photonic device is a liquid crystal display
device. In some embodiments, the cured film is in a sub-pixel cell
of a color filter and the photonic device is a liquid crystal
display device.
EXAMPLES
Example 1: Ligands without Polymerizable Functional Groups
TABLE-US-00001 [0147] TABLE 1 Carboxylic Acid Ligand Structure
Guide--Non-Polymerizable End Groups Ligand length, Denticity Ligand
Name in atoms Monodentate EG4SA 18 EG4SA2X Bidentate EG4.3TSA 20
EG4.3OSA 19
[0148] A. Synthesis of EG4SA2X, a Dicarboxylic Acid, from
Tetraethylene Glycol and Succinic Anhydride
##STR00006##
[0149] General:
[0150] The reagents and solvents were purchased from Aldrich and
used without further purification. The starting materials,
tetraethylene glycol and succinic anhydride, were stored and
transferred in air. The toluene and pyridine were stored and
handled under nitrogen gas. FTIR analysis was obtained on a Nicolet
6700 spectrometer equipped with a Smart iTR Attenuated Total
Reflectance (ATR) Sampling Accessory. Mass spectroscopy analysis
was obtained by Scripps MS Center for Metabolomics and Mass
Spectrometry.
[0151] Synthetic Procedure: To a 20 mL clear glass vial equipped
with a small stir bar were added succinic anhydride (6.73 g, 67.2
mmoles) followed by tetraethylene glycol (6.47 g, 33.3 mmoles), and
the vial was closed with a septum screw cap. Positive pressure of
nitrogen was maintained in the vial using a needle through the
septum cap. The headspace of the vial was gently purged for 15 min
by piercing the septum with another needle to release the gas into
the air. The vent needle was removed and pyridine (132 mg, 1.66
mmoles or 0.025 eq) was added by syringe after transfer in the
glove box. Then the mixture was heated in a heat block that was
thermostat controlled at 90.degree. C., which melted the solids and
produced a clear, colorless, homogenous solution. The reaction
solution was heated at 90.degree. C. for 16 h or overnight. A
sample was prepared for FTIR analysis by removing the volatiles by
vacuum. That analysis showed that the C.dbd.O peaks of succinic
anhydride at 1859 cm.sup.-1 and 1775 cm.sup.-1 had been replaced by
C.dbd.O peaks at 1728 cm.sup.-1 and 1708 cm.sup.-1. The alcohol
absorbance 3500 had also been replaced by a broad absorbance
between 3500 cm.sup.-1 and 2500 cm.sup.-1 for the carboxylic acid.
Following analysis that suggested the reaction was complete, the
heating block temperature was reduced to 60.degree. C. and dry
toluene (10 mL) was added to the reaction solution. The reaction
mixture was dissolved in toluene and a vent needle was inserted
into the septum to purge the headspace above the solution with a
stream of nitrogen gas. The toluene was evaporated while the
solution temperature was maintained at about 60.degree. C. with the
heat block. The toluene azeotrope purification/drying step was
performed four times to produce a clear colorless product.
Ultimately, the product was isolated by vacuum while being stirred
in a desiccator to a pressure of less than 50 mtorr overnight. The
product was a slightly viscous clear colorless oil. The hygroscopic
product was stored in a glove box.
[0152] Analytical:
[0153] FTIR (diamond, cm.sup.-1): 3500-2500 (broad, carboxylic
acid), 1728, 1708 (s, C.dbd.O), 1157 (s, C--O--C).
[0154] B. Synthesis of EG4SA, a Monocarboxylic Acid Ligand, Via
Alcohol Addition to Succinic Anhydride
##STR00007##
[0155] General:
[0156] The reagents and solvents were purchased from Aldrich and
used without further purification. The starting materials
tetraethylene glycol monomethyl ether and succinic anhydride were
stored and transferred in air. The toluene and pyridine were stored
and handled under nitrogen gas.
[0157] Synthetic Procedure:
[0158] To a 100 mL RBF equipped with a thermocouple attached to a
temperature control unit and heating mantle, magnetic stirrer,
stopper, and nitrogen inlet adapter were added tertaethylene glycol
monomethyl ether (12.00 g, 57.6 mmoles) and succinic anhydride
(5.77 g, 57.6 mmoles). The thermocouple tip was adjusted to monitor
the reaction solution temperature, and the mixture was heated to
80.degree. C., which dissolved the succinic anhydride. Then
pyridine (0.228 g, 0.233 mL, 2.88 mmoles) was added by syringe and
the reaction solution was maintained at 80.degree. C. overnight. A
sample was prepared for FTIR analysis by removing the volatiles by
vacuum. FTIR analysis showed that the C.dbd.O peaks of succinic
anhydride at 1859 cm.sup.-1 and 1775 cm.sup.-1 had been replaced by
C.dbd.O a peak at 1730 cm.sup.-1. The alcohol absorbance at 3500
cm.sup.-1 for tertaethylene glycol monomethyl ether had also been
replaced by a broad absorbance between 3500 cm.sup.-1 and 2500
cm.sup.-1 for the carboxylic acid. Due to this data, the reaction
was considered complete, and the reaction flask was then modified
by removal of the stopper opposite to the nitrogen inlet adapter
and replaced by a short path distillation head equipped with a 100
mL receiving flask. Nitrogen gas was adjusted to pass across the
surface of the solution from the nitrogen inlet adapter to the
distillation head. Toluene (40 mL) was added and the solution was
maintained at 80.degree. C. to distill the toluene into the
receiver. After distillation, toluene was added three more times
followed by distillation to remove impurities by toluene azeotrope.
The distillation head was then replaced by a stopper and the
reaction solution was cooled to 40.degree. C. while vacuum was
applied to the reaction flask. The volatiles were removed by vacuum
overnight while the reaction solution temperature was maintained at
40.degree. C. The product, a clear colorless oil, was stored in the
glove box.
[0159] Analytical:
[0160] Product FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad,
carboxylic acid), 1730 (s, C.dbd.O), 1095 (s, C--O--C).
[0161] ESI TOF MS: m/z (% relative intensity, ion): Positive 412
(50%, Tetramer+3Na+2H.sub.2O), Negative 393 (100%,
Tetramer+2Na+K).
[0162] C. Synthesis of EG4.3TSA, a Bidentate Dicarboxylic Acid,
from Metcaptosuccinic Acid and Allyloxy(tetraethylene oxide) Methyl
Ether
##STR00008##
[0163] General:
[0164] The reagents and solvents were purchased from Aldrich and
used without further purification, with the exception of
allyloxy(tetraethylene oxide) methyl ether that was purchased from
Gelest. The starting materials, metcaptosuccinic acid and
allyloxy(tetraethylene oxide) methyl ether, were stored and
transferred in the glove box under nitrogen gas. The solvents,
toluene and pyridine, were also stored and handled under nitrogen
gas. FTIR analysis was obtained on a Nicolet 6700 spectrometer
equipped with a Smart iTR Attenuated Total Reflectance (ATR)
Sampling Accessory. Mass spectroscopy analysis was obtained by
Scripps MS Center for Metabolomics and Mass Spectrometry.
[0165] Synthetic Procedure:
[0166] To a 100 mL RBF equipped with a nitrogen inlet adapter, stir
bar and stoppers was added in the glove box metcaptosuccinic acid
(12.0 g, 79.9 mmoles), and the flask was then connected to the
vacuum line. After attachment to the vacuum line, the middle
stopper was replaced by a thermocouple and allyloxy(tetraethylene
oxide) methyl ether (21.8 g, 87.9 mmoles) was added by syringe.
Pyridine (0.632 g, 0.646 mL or 7.99 mmoles) was also added to the
reaction solution by syringe. The thermocouple and heating mantle
were connected to a temperature controller and the reaction
solution was heated to 90.degree. C., which dissolved the
metcaptosuccinic acid and formed a clear straw yellow solution. The
yellow color was imparted into the solution by the light straw
yellow allyloxy(tetraethylene oxide) methyl ether. The reaction
solution was heated at 90.degree. C. overnight. Following heating
for 16 h, the reaction was about the same straw yellow color as the
night before. The reaction solution was sampled and the volatiles
were removed from that sample to prepare them for FTIR analysis.
Before volatiles removal, the sample smelled like a sulfur organic
compound. The sample was vacuumed until a pressure of <100 mtorr
was reached. FTIR analysis showed that the S--H peaks, from
starting metcaptosuccinic acid centered at 2564 cm.sup.-1, had
almost disappeared and the C.dbd.O peak from metcaptosuccinic acid
at 1681 cm.sup.-1 had shifted to 172.9 cm.sup.-1, suggesting the
reaction had proceeded to completion. The reaction apparatus was
modified by removal of the stopper followed by replacement with a
short path distillation apparatus equipped with a 100 mL receiver
flask. Nitrogen gas was sent through the apparatus gently from the
nitrogen inlet adapter across the surface of the solution and out
the short path distillation head to the air. Then toluene (40 mL)
was added and the toluene was distilled slowly with the assistance
of flowing, nitrogen gas. Upon completion of distillation of the
first aliquot of toluene, the process was repeated four more times.
Upon completion of toluene distillation/product purification, the
short path distillation head was replaced by a stopper and the
reaction solution was placed under vacuum while the temperature was
allowed to decrease to 60.degree. C. The product was purified by
vacuum overnight as the pressure dropped to <50 mtorr. The
product, a clear light yellow oil, was then transferred into the
glove box and stored in a vial.
[0167] Analytical:
[0168] FTIR (diamond, cm.sup.-1): 1729 (m, C.dbd.O) and 1084 (s,
C--O--C).
[0169] ESI TOF MS: m/z (% relative intensity, ion): Positive 354
(40%, M-CO.sub.2H), 372 (65%, M-CO.sub.2H+H.sub.2O), 398 (20%, M+H
for n=4), 416 (25%, M+H.sub.2O) and negative 397 (15%, M-H).
[0170] D. Synthesis of EG4.3OSA, a Bidentate Dicarboxylic Acid,
from Maleic Anhydride Acid and Allyloxy(tetraethylene Oxide) Methyl
Ether
##STR00009##
[0171] General:
[0172] The reagents and solvents were purchased from Aldrich and
used without further purification, with the exception of
allyloxy(tetraethylene oxide) methyl ether that was purchased from
Gelest. The starting materials, maleic anhydride and activated
charcoal, were stored and handled in the air, while
allyloxy(tetraethylene oxide) methyl ether and dimethyltin
dichloride were stored and handled in the glove box under nitrogen
gas. Toluene and ethyl acetate were also stored and handled under
nitrogen gas. FTIR analysis was obtained on a Nicolet 6700
spectrometer equipped with a Smart iTR Attenuated Total Reflectance
(ATR) Sampling Accessory. Mass spectroscopy analysis was obtained
by Scripps MS Center for Metabolomics and Mass Spectrometry.
[0173] Synthesis of the Anhydride:
[0174] To a 20 mL clear glass vial was added maleic anhydride (1.00
g, 10.2 mmoles) in air, and the vial then was pumped into the glove
box antechamber. Once the vial was inside the glove box,
allyloxy(tetraethylene oxide) methyl ether (2.53 g, 10.2 mmoles)
was added. Dimethyltin dichloride (0.22 mg, 1.0 micromoles) was
then added, the vial was closed, and the reaction solution was
heated on a thermostat-controlled heat block at 90.degree. C.
overnight. The reaction solution was a colorless slurry upon
combination, but upon reaching 90.degree. C. the maleic anhydride
dissolved and the solution became a clear, colorless oil. After
being heated overnight at 90.degree. C., the reaction solution
remained a clear, colorless oil. A sample was removed and, after a
brief vacuum, analyzed by FTIR. The C.dbd.O peaks of the maleic
anhydride at 1800 cm.sup.-1 and 1855 cm.sup.-1 (symm and asymm) had
been shifted to 1776 cm.sup.-1 and 1848 cm.sup.-1, which suggested
that the reaction had gone to completion. The reaction solution was
cooled to room temperature, and tin impurities were removed with
activated charcoal. A sample of the anhydride (1.00 g, 2.89 mmoles)
was dissolved in 1.0 mL toluene, and 100 mg of activated charcoal
was added. The resulting slurry was stirred overnight and then
filtered through fine glass wool, followed by a 0.45 um nylon
syringe filter into a 20 mL vial. After the initial filtration, the
filter apparatus was rinsed with another 3 mL of toluene, and that
filtrate was combined with the product to produce a clear,
colorless solution. The anhydride was hydrolyzed by the addition of
water (1.30 g, 1.30 mL, 72.2 mmoles) to the same vial, and the
reaction solution was heated at 90.degree. C. for 90 min. A small
0.2 mL portion of the reaction solution was transferred to a
separate vial, and the volatiles were removed with flowing nitrogen
gas followed by vacuum, leaving an opaque paste. Analysis of the
paste by FTIR showed one C.dbd.O peak at 1731 cm.sup.-1 and a broad
adsorption for carboxylic acid between 3500 cm.sup.-1 and 2500
cm.sup.-1, indicating that succinic anhydride had been hydrolyzed
to succinic acid. The volatiles were removed by toluene azeotrope
using flowing nitrogen, while the vial containing the reaction
solution was held in a thermostat-controlled heat block at
50.degree. C. Once the product had been reduced to a paste, ethyl
acetate (10 mL) was added, and an ethyl acetate water azeotrope was
used to remove the water at 30.degree. C. Finally, ethyl acetate
(10 mL) water azeotrope was used again to dry the product to a
paste followed by subjecting the product to two days at a pressure
of less than 50 mtorr. The product was an opaque, but flowing, very
light yellow oil.
[0175] Anhydride Analytical Data:
[0176] FTIR (diamond, cm.sup.-1): 3083 (w, olefin C--H), 1848 (m,
C.dbd.O) and 1776 (s, C.dbd.O) anhydride symm and asymm, 1094 (s,
C--O--C).
[0177] ESI TOF MS: m/z (% relative intensity, ion): Positive 249
(40%, M-CO.sub.2H--CH.sub.2O-2CH.sub.2), 266 (85%,
M-CO.sub.2H--CH.sub.2O-2CH.sub.2+H.sub.2O), 293 (40%,
M-CO.sub.2H--CH.sub.2O+H.sub.2O), 310 (100%,
M-CO.sub.2H--CH.sub.2O--CH.sub.2+Li+Na+H.sub.2O), 354 (50%,
M-O+Na), Negative 287 (100%,
M-CO.sub.2H--CH.sub.2O--CH.sub.2+Li+H.sub.2O), 331 (90%,
M-CO.sub.2H--CH.sub.2O--CH.sub.2+Li+Na+K).
[0178] Acid Analytical Data:
[0179] FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad, carboxylic
acid OH), 1731 (m, C.dbd.O) and 1084 (s, C--O--C).
[0180] ESI TOF MS: m/z (% relative intensity, ion): Positive 266
(100%, M-O(CH.sub.2CH.sub.2O)2CH.sub.3+H.sub.2O+H), 266 (100%,
M-CO.sub.2H--O(CH.sub.2).sub.2OCH.sub.3+H.sub.2O+H), 222 (20%,
M-O(CH.sub.2CH.sub.2O)3CH.sub.3+H.sub.2O+H), 222 (20%,
M-CO.sub.2H--O(CH.sub.2CH.sub.2O)2CH.sub.3+H.sub.2O+H), 249 (20%,
M-CO.sub.2H--CH.sub.2O(CH.sub.2).sub.2OCH.sub.3+H.sub.2O), 271
(20%, M-O(CH.sub.2CH.sub.2O)2CH.sub.3+Na+H), 271 (20%,
M-CO.sub.2H--O(CH.sub.2).sub.2OCH.sub.3+H.sub.2O+Li), 310 (20%,
M-CO.sub.2H--OCH.sub.3+H.sub.2O+H).
TABLE-US-00002 TABLE 2 Amine Ligand Structure Guide--Polymerizable
End Groups Ligand Ligand length, Denticity Name in atoms
Monodentate MADMI 30 A2MI 6 A4MI 8 A8MI 10 DA2MI 9 Bidentate DADMI
31 Tridentate TAMMI 31
[0181] E. Synthesis of A2MI, A4MI and A8MI, Amines with Maleimide
from their Respective Diamine
##STR00010##
[0182] General:
[0183] The reagents and solvents were purchased from Aldrich and
used without further purification. However, the amines were stored
and transferred in the glove box. The reagent handling and
reactions were performed under nitrogen, except where noted. FTIR
analysis was obtained on a Nicolet 6700 spectrometer equipped with
a Smart iTR Attenuated Total Reflectance (ATR) Sampling Accessory.
Mass spectroscopy analysis was obtained by Scripps MS Center for
Metabolomics and Mass Spectrometry.
[0184] Synthetic Procedure:
[0185] To a 20 mL amber vial was added 1,8-diaminooctane (0.868 g,
6.02 mmoles) in the glove box, and the vial was capped with a
septum cap. The vial was then connected to the vacuum line through
a syringe needle and de-gassed water (10 mL) was added by syringe,
which dissolved the amine and produced a clear solution. Then
exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride (1.00 g, 6.02
mmoles) was weighed into a vial in the air. The vial was connected
to the vacuum line with a needle and purged with a vent needle
using nitrogen gas. Acetonitrile (8 mL) was added to the vial, and
the solution was heated slightly to dissolve the anhydride and
produce a clear solution before it was drawn into a syringe. The
reaction solution of di-amine in water, connected to the vacuum
line, then was heated in a thermostat-controlled heat block
maintained at 70.degree. C., and the anhydride was added dropwise
to the center of the vortex over 5 min. The reaction solution was
stirred at 70.degree. C. overnight. The volatiles were then removed
with flowing nitrogen gas while the vial was in a heat block
maintained at 30.degree. C. A small sample was placed under vacuum
in a desiccator to prepare it for analysis. FTIR analysis showed
the anhydride peaks at 1857 cm.sup.-1 and 1778 cm.sup.-1 had been
replaced by maleimide C.dbd.O at peaks 1769 cm.sup.-1 and 1693
cm.sup.-1. The C.dbd.O peaks also appeared to be the typical
maleimide peak (symm and asymm) pattern, suggesting that the
reaction had gone to completion. There was also an amine peak at
3321 cm.sup.-1, although the peak was obscured by a substantial
amount of hydrogen bonded water. Dimethoxyethane (DME, 10 mL) then
was added to the oily product, and after mixing the volatiles were
removed with flowing nitrogen gas using a vent needle while in a
heat block maintained at 30.degree. C. DME (10 mL) was added to dry
the product two more times, and the product was placed under vacuum
in a desiccator and stirred overnight. The product was a white
crystalline powder.
[0186] Analytical:
[0187] Product FTIR (diamond, cm.sup.-1): .about.3450 and 3321 (m,
secondary amine) 3069 (w, olefin C--H), 1769 (sh, C.dbd.O), 1693
(s, C.dbd.O); both are maleimide symm and asymm.
[0188] ESI TOF MS: m/z (% relative intensity, ion): Positive 243
(50%, M+H.sub.2O+H), 268 (40%, M+2Na), 293 (85%, M+3Na), 311 (100%,
M+3Na+H.sub.2O), negative 241 (35%, M+H.sub.2O--H).
[0189] For n=2 and 4, the procedure and solvent amounts were the
same.
[0190] For n=2, 1,2-diaminoethane (0.362 g, 6.02 mmoles) and
exo-3,6-Epoxy-1,2,3,6-tetrahydrophthalic anhydride (1.00 g, 6.02
mmoles) were used. The product was a white crystalline powder.
[0191] Analysis:
[0192] Product FTIR (diamond, cm.sup.-1): 3371 and 3299 (m,
secondary amine), 3071 (w, olefin C--H), 1760 (w, maleimide
C.dbd.O) and 1691 (s, maleimide C.dbd.O) symm and asymm.
[0193] ESI TOF MS: m/z (% relative intensity, ion): Positive 209
(50%, M+3Na), 157 (50%, M+H.sub.2O--H) and negative 433 (65%,
2M+3H.sub.2O).
[0194] For n=4, 1,4-diaminobutane (0.531 g, 6.02 mmoles and
exo-3,6-Epoxy-1,2,3,6-tetrahydrophthalic anhydride (1.00 g, 6.02
mmoles) was used. The product was a white crystalline powder.
[0195] Analysis:
[0196] Product FTIR (diamond, cm.sup.-1): .about.3400 and 3280 (m,
secondary amine), 3073 (w, olefin C--H), 1769 (w, maleimide
C.dbd.O) and 1692 (s, maleimide C.dbd.O) symm and asymm.
[0197] ESI TOF MS: m/z (% relative intensity, ion): Positive 237
(100%, M+3 Na) and negative 421 (35%, 2M+3 Na H.sub.2O).
[0198] F. Synthesis of DA2MI, Amines with Maleimide from their
Respective Triamine
##STR00011##
[0199] General:
[0200] The reagents and solvents were purchased from Aldrich and
used without further purification. However, the amines were stored
and handled in the glove box. The reagent handling and reaction
were performed under nitrogen, except where noted. FTIR analysis
was obtained on a Nicolet 6700 spectrometer equipped with a Smart
iTR Attenuated Total Reflectance (ATR) Sampling Accessory. Mass
spectroscopy analysis was obtained by Scripps MS Center for
Metabolomics and Mass Spectrometry.
[0201] Synthetic Procedure:
[0202] To a 20 mL amber vial was added diethylenetriamine (0.621 g,
6.02 mmoles) in the glove box, and then the vial was capped with a
septum cap. The vial was then connected to the vacuum line through
a syringe needle, and de-gassed water (10 mL) was added by syringe,
which dissolved the amine and produced a clear solution. Then
exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride (1.00 g, 6.02
mmoles) was weighed into a vial in the air. The vial was connected
to the vacuum line with a needle and purged with a vent needle
using nitrogen gas. Acetonitrile (8 mL) was added to the vial, and
the solution was heated slightly to dissolve the anhydride before
the clear solution was drawn into a syringe. The reaction solution
of di-amine in water, connected to the vacuum line, was then heated
in a thermostat-controlled heat block maintained at 70.degree. C.,
and the anhydride was added dropwise to the center of the vortex
over 5 min. The reaction solution was stirred at 70.degree. C.
overnight. The volatiles were then removed with flowing nitrogen
gas while the vial was in a thermostat-controlled heat block
maintained at 30.degree. C. A small sample was placed under vacuum
in a desiccator to prepare it for analysis. FTIR analysis showed
the anhydride peaks at 1857 cm.sup.-1 and 1778 cm.sup.-1 had been
replaced by maleimide C.dbd.O at peaks 1769 cm.sup.-1 and 1692
cm.sup.-1. Also, the C.dbd.O peaks appeared as the typical
maleimide peak pattern (symm and asymm), suggesting that the
reaction had gone to completion. There was also an amine peak at
3321 cm-1, although the peak was obscured by a substantial amount
of hydrogen bonded water. Dimethoxyethane (DME, 10 mL) was then
added to the oily product and, after mixing, the volatiles were
removed with flowing nitrogen gas using a vent needle while in a
heat block maintained at 30.degree. C. DME (10 mL) was added two
more times to dry the product, and the product was placed under
vacuum in a desiccator and stirred overnight. The product was a
clear oil.
[0203] Analytical:
[0204] Product FTIR (diamond, cm.sup.-1): 3283 (w, amine), 3076 (w,
olefin C--H), 1769 (sh, maleimide C.dbd.O) and 1692 (s, maleimide
C.dbd.O) symm and asymm.
[0205] ESI TOF MS: m/z (% relative intensity, ion): Positive 184
(30%, M+H), 252 (100%, M+3Na) and negative 547 (100%, 3M-H).
[0206] G. Synthesis of DCA10A, a Dicarboxylic Acid Monoamine from
the Reaction of Tris(2-aminoethyl)amine and Succinic Anhydride
##STR00012##
[0207] General:
[0208] The reagents and solvents were purchased from Aldrich and
used without further purification. However, the amine was stored
and transferred in the glove box. The reagent handling and reaction
were performed under nitrogen. FTIR analysis was obtained on a
Nicolet 6700 spectrometer equipped with a Smart iTR Attenuated
Total Reflectance (ATR) Sampling Accessory. Mass spectroscopy
analysis was obtained by Scripps MS Center for Metabolomics and
Mass Spectrometry.
[0209] Synthetic Procedure:
[0210] To a 20 mL clear glass vial in the glove box
tris(2-aminoethyl)amine (1.00 g, 6.84 mmoles) was dissolved in
methanol (5.0 mL) to form a clear solution. The vial was closed
with a septum cap. In a separate vial, succinic anhydride (1.37 g,
13.7 mmoles) was dissolved in methanol (5.0 mL) and
dimethylformamide (DMF, 5.0 mL). The succinic anhydride solution
was pulled into a syringe. The tris(2-aminoethyl)amine solution in
the vial was then stirred at 30.degree. C. in a
thermostat-controlled heat block while the succinic anhydride
solution was added dropwise into the vortex over 5 min. The
resulting clear, colorless reaction solution was then stirred
overnight. A reaction sample was subjected to vacuum to prepare it
for analysis. FTIR analysis showed loss of the starting succinic
anhydride C.dbd.O peaks at 1857 cm.sup.-1 and 1778 cm.sup.-1 (symm
and asymm), and the appearance of peaks at 1725 cm.sup.-1 for
carboxylic acid C.dbd.O and 1648 cm.sup.-1 for amide C.dbd.O. In
addition, there was a broad absorbance between 3500 cm.sup.-1 and
2500 cm.sup.-1 for the hydrogen bonded carboxylic acid. The FTIR
data suggested that the reaction was complete. The reaction volume
was about 15 mL when the volatiles were removed with flowing
nitrogen gas, and when the volume reached about 10 mL the solution
transformed into opaque white. When the reaction solution had been
reduced to a paste, ethyl acetate (5.0 mL) was added and the
reaction solution temperature was maintained at about 30.degree. C.
in the thermostat-controlled heating block, while the volatiles
were removed with flowing nitrogen gas. Toluene (5.0 mL) was added
six times, and the volatiles were removed with flowing nitrogen gas
while in the heat block. The vial then was placed into the
desiccator to remove the last of the volatiles overnight. Finally,
the product was dissolved in methanol (5.0 mL), and toluene (about
4 to 8 mL) was added to precipitate the product. After removal of
the supernatant, the precipitate was dried by vacuum overnight. The
product was a thick, straw yellow oil.
[0211] Analytical:
[0212] Product FTIR (diamond, cm.sup.-1): 3266 cm-1 (m, amine),
3500 to 2500 (broad, carboxylic acid), 1709 (sh, carboxylic acid),
1634 (m, amide C.dbd.O), 1535 (s, amide N--H).
[0213] ESI TOF MS: m/z (% relative intensity, ion): Positive 347
(90%, M+H), 693 (20%, 2M+H), Negative 345 (20%, M-H).
[0214] H. Synthesis of DCAMI, a Dicarboxylic Acid Ligand, with
Maleimide
##STR00013##
[0215] General:
[0216] The reagents and solvents were purchased from Aldrich and
used without further purification. However, the amine/carboxylic
acid was stored and transferred in the glove box. The reagent
handling and reaction were performed under nitrogen, except where
noted. FTIR analysis was obtained on a Nicolet 6700 spectrometer
equipped with a Smart iTR Attenuated Total Reflectance (ATR)
Sampling Accessory. Mass spectroscopy analysis was obtained by
Scripps MS Center for Metabolomics and Mass Spectrometry.
[0217] Synthetic Procedure:
[0218] To a 20 mL amber vial the amine/carboxylic acid (2.08 g,
6.02 mmoles) was transferred in the glove box, and the vial was
closed with a septum cap. The vial was attached to the vacuum line
by a syringe needle and dissolved in degassed water (10 mL) to form
a clear solution. The exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic
anhydride (1.00 g, 6.02 mmoles) was transferred to a vial and
dissolved in acetonitrile (5.0 mL) before being drawn into a
syringe. The solution of amine in the vial then was stirred in a
30.degree. C. thermostat-controlled heat block while the solution
of anhydride was added by syringe into the reaction solution vortex
dropwise over 5 min. The reaction solution was then stirred under
nitrogen gas atmosphere at 30.degree. C. in a thermostat-controlled
heat block overnight. A small sample was prepared for analysis by
removal of volatiles by vacuum. FTIR analysis showed loss of the
anhydride C.dbd.O peaks at 1857 cm.sup.-1 and 1778 cm.sup.-1, along
with the appearance of product peaks at 1769 cm.sup.-1 and 1687
cm.sup.-1 in the characteristic pattern for a cyclic maleimide ring
system (symm and asymm), suggesting that the reaction was complete.
The volatiles were removed using nitrogen gas and a vent needle on
the vacuum line. Once the volume had been substantially reduced,
ethyl acetate (10 mL) was added, followed by removal of volatiles
with flowing nitrogen gas while the vial was being heated in the
heat block at 30.degree. C. This ethyl acetate (10 mL) addition
followed by flowing nitrogen etc. then was performed once again,
and the product was isolated by vacuum to yield a white
semi-crystalline solid. The product was stored in the glove
box.
[0219] Analytical:
[0220] Product FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad,
carboxylic acid), 1769 (sh, maleimide), 1688 (s, maleimide and
carboxylic acid), .about.1680 (sh, carboxylic acid).
[0221] ESI TOF MS: m/z (% relative intensity, ion): Positive 443
(25%, M+H.sub.2O--H), 429 (35%, M-CO.sub.2H+2Na+H), Positive 477
(55%, M-CO.sub.2H+2K+H.sub.2O), Positive 411 (100%,
M-CO.sub.2H+Na+Li), Negative 427 (15%, M+H).
[0222] I. Synthesis of TR14A, a Nanocrystal Intermediate Intended
to Produce a Nanocrystal Ligand to Covalently Bond the Nanocrystals
into an Acrylate Cure Matrix
##STR00014##
[0223] General:
[0224] The reagents and solvents were purchased from Aldrich and
used without further purification. However, the amine was stored
and transferred in the glove box. The reaction was performed under
clean dry air (CDA). FTIR analysis was performed on a Nicolet 6700
spectrometer equipped with a Smart iTR Attenuated Total Reflectance
(ATR) Sampling Accessory. Mass spectroscopy analysis was performed
at Scripps MS Center for Metabolomics and Mass Spectrometry.
[0225] Synthetic Procedure:
[0226] To a 20 mL amber glass vial in the glove box was added
bis(3-aminopropyl)amine (1.16 g, 8.86 mmoles), which was then
dissolved in methanol (10 mL). The vial was capped with a septum
cap. To another vial then was added trimethylolpropane
trimethacrylate (1.00 g, 2.95 moles), and it was dissolved in
methanol (5.0 mL) under CDA. The acrylate was then transferred into
a syringe. Under a CDA atmosphere, the solution of acrylate was
added to the solution of triamine dropwise over 5 min. The two
solutions were clear and colorless before combination, and clear
and colorless afterward, but the reaction solution became slightly
warm upon the addition of acrylate. The reaction solution then was
stirred overnight at room temperature under CDA. Samples removed 20
min after addition and, after stirring overnight, appeared to be
the same after FTIR analysis. The product was isolated by addition
of 5 mL toluene, followed by removal of the volatiles with flowing
nitrogen gas. The product then was placed under a vacuum overnight,
leaving an opaque, white semi-solid.
[0227] Analytical: Trimethylolpropane trimethacrylate FTIR
(diamond, cm.sup.-1): 3104 (w, olefin C--H), 1715 (s, C.dbd.O).
[0228] Product FTIR (diamond, cm.sup.-1): 3278 and 3182 (w, amine)
and 1728 (s, C.dbd.O).
[0229] ESI TOF MS: m/z (% relative intensity, ion): positive 232
(100%,
M-2NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NHCH.sub.2CH(CH.sub.3)CO--NH-
.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.2+H), 331 (85%,
M-2NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NHCH.sub.2CH(CH.sub.3)CO--NH-
.sub.2+2Li--H), 431 (75%,
M-NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NHCH.sub.2CH(CH.sub.3)CO--NH.-
sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NH.sub.2CH.sub.2CH(CH.sub.3)+3Na+H)-
, 531 (25%,
M-NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NHCH.sub.2CH(CH.sub.3)CO--H),
631 (15%, M-NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.2) and
Negative 375 (35%,
M-NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NHCH.sub.2CH(CH.sub.3)C-
O--NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NHCH.sub.2CH(CH.sub.3)+2Li),
443 (20%,
M-NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NHCH.sub.2CH(CH.sub-
.3)CO--NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3+H.sub.2O+Li), 575
(35%,
M-NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NHCH.sub.2CH(CH.sub.3)+2Li)
and 773 (10%, M+Na+H.sub.2O+H).
[0230] J. Synthesis of TE14A, a Dodecylamine Intermediate Intended
for Production of a Nanocrystal Ligand to Bond the Nanocrystals
into an Acrylate Cure Matrix
##STR00015##
[0231] General:
[0232] The reagents and solvents were purchased from Aldrich and
used without further purification. However, the amine was stored
and transferred in the glove box. The reagent handling and reaction
were performed under clean dry air (CDA), as noted. FTIR analysis
was obtained on a Nicolet 6700 spectrometer equipped with a Smart
iTR Attenuated Total Reflectance (ATR) Sampling Accessory. Mass
spectroscopy analysis was obtained by Scripps MS Center for
Metabolomics and Mass Spectrometry.
[0233] Synthetic Procedure:
[0234] To a 20 mL vial in the glove box was added
bis(3-aminopropyl)amine (2.98 g, 22.7 mmoles), which was then
dissolved in methanol (8 mL). The vial was capped with a septum
cap. Pentaerythritol tetraacrylate (1.00 g, 3.84 mmoles) was added
to a vial and dissolved in methanol (5 mL) and then pulled into a
syringe. The 20 mL vial then was placed under CDA and the acrylate
was added dropwise over 5 min. Both solutions were clear and
colorless before addition, and the reaction solution remained clear
colorless after the addition. The reaction solution also became a
little warm upon reagent combination. The reaction solution was
stirred overnight at room temperature under CDA. Samples removed 20
min after addition and after stirring overnight were essentially
the same according to FTIR analysis. The product was isolated by
adding 5 mL toluene followed by removing the volatiles with flowing
nitrogen gas. The product was then placed under vacuum overnight,
leaving an opaque, white, oily solid.
[0235] Analytical:
[0236] Pentaerythritol tetraacrylate FTIR (diamond, cm.sup.-1):
1720 (s, C.dbd.O).
[0237] Product FTIR (diamond, cm.sup.-1): 1733 (m, C.dbd.O), 1652
(s, primary NH.sub.2 scissoring).
[0238] ESI TOF MS: m/z (% relative intensity, ion): Positive 317
(100%,
M-3NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NH(CH.sub.2).sub.3CO--NH.sub-
.2CH.sub.2+Na+H), 502 (35%,
M-2NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NH(CH.sub.2).sub.3CO--NH.sub-
.2CH.sub.2+Na+H) and 688 (15%,
M-NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NH(CH.sub.2).sub.3CO--NH.sub.-
2CH.sub.2+Li-H). Negative 361 (60%,
M-3NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NH(CH.sub.2).sub.3CO+Na+H.su-
b.2O--H), 366 (60%,
M-2NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NH(CH.sub.2).sub.3CO-2NH.sub-
.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NH(CH.sub.2).sub.3.+-.H.sub.2O--H),
546 (60%,
M-2NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NH(CH.sub.2).sub.3-
CO+Na+H.sub.2O--H), 551 (25%,
M-NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NH(CH.sub.2).sub.3CO--NH.sub.-
2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NH(CH.sub.2).sub.3+H.sub.2O--H),
732 (25%,
M-NH.sub.2(CH.sub.2).sub.3NH(CH.sub.2).sub.3NH(CH.sub.2).sub.3CO+Na-
+H.sub.2O--H) and 917 (8%, M+Na+H.sub.2O--H).
Example 2: Carboxylic Acid Ligands with Polymerizable Functional
Groups
TABLE-US-00003 [0239] TABLE 3 Carboxylic Acid Ligand Structure
Guide--Polymerizable End Groups Meth (Meth) (Acrylate) Maleimide
Acrylate Ligand Maleimide Ligand Ligand Length, Ligand Length, in
Density Name in atoms Name atoms Bidentate DCAMI 13 DCA17A 17
DCAD2MI 22 DCAD2MI 24 DCAD8MI 28 DCAD2AMI 25 DCA17MA 17 DCAM2MI 24
DCAM4MI 28 DCAM8MI 32 DCAM2AMI 29 DCA7MA 17 DCA2MI 29 DCA4MI 31
DCA8MI 34 DCA2D2AMI 31
[0240] A. Synthesis of DCA17A, a Dicarboxylic Acid, Diacrylate
Ligand for Nanocrystal Stabilization and Covalent Bonding into the
Acrylate Cure Matrix
##STR00016##
[0241] General:
[0242] The reagents and solvents were purchased from Aldrich and
used without further purification. However, the amine was stored
and transferred in the glove box. The reagent handling and reaction
were performed under clean dry air (CDA) as noted. FTIR analysis
was obtained on a Nicolet 6700 spectrometer equipped with a Smart
iTR Attenuated Total Reflectance (ATR) Sampling Accessory. Mass
spectroscopy analysis was obtained by Scripps MS Center for
Metabolomics and Mass Spectrometry.
[0243] Synthetic Procedure:
[0244] To a 20 mL amber vial under CDA were added
11-aminoundecanoic acid (1.14 g, 5.68 mmoles) and methanol (5 mL),
which formed a slurry. The vial was closed with a septum cap.
Pentaerythritol tetraacrylate (1.00 g, 2.84 mmoles) then was added
to a separate vial and dissolved in methanol (5 mL) to produce a
clear, colorless solution. The acrylate was drawn into a syringe,
and the vial containing the amine solution was placed under CDA.
The amine solution was added to the acrylate solution dropwise over
5 min. Upon this addition, the reaction solution became an opaque,
white slurry that had become slightly warm. The solution was
stirred overnight at room temperature. Samples of the reaction
solution were removed for analysis after about 30 min, and
overnight, and analyzed after removal of volatiles. The C.dbd.O
peaks from pentaerythritol tetraacrylate at 1720 cm.sup.-1 had
shifted to 1725 cm.sup.-1, which is not a very large shift.
However, the NH.sub.2 peak at 3111 cm.sup.-1 had disappeared into
the hydrogen bonded carboxylic acid absorbance between 3500
cm.sup.-1 and 2500 cm.sup.-1. Both of these factors suggested that
the reaction had gone to completion. The reaction solution was
isolated by adding toluene (5 mL), followed by removing volatiles
with flowing nitrogen gas and vacuum. The product was an opaque,
white semi-solid.
[0245] Analytical:
[0246] Pentaerythritol tetraacrylate FTIR (diamond, cm.sup.-1):
1720 (s, C.dbd.O).
[0247] Product FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad,
hydrogen bonded carboxylic acid, .about.3025 (sh, olefin C--H),
1725 (s, C.dbd.O), 1634 (m, C.dbd.C).
[0248] ESI TOF MS: m/z (% relative intensity, ion): Negative 939
(20%, M+Na+2NH.sub.4Cl+3H.sub.2O), 885 (15%, M+Na+2NH.sub.4Cl), 794
(10%, M+Na+H.sub.2O--H), 713 (25%, M-CO.sub.2H+H.sub.2O), 641 641
(100%, M-HO.sub.2C(CH.sub.2).sub.5--H), 587 (100%,
M-HO.sub.2C(CH.sub.2)10-H), 401 (15%,
M-HO.sub.2C(CH.sub.2)10NH.sub.2--HO.sub.2C(CH.sub.2)8+H), 200 (40%,
2 M-HO.sub.2C(CH.sub.2)10NH.sub.2--HO.sub.2C(CH.sub.2)8+H).
[0249] B. Synthesis of DCA17MA, a Dicarboxylic Acid
Monomethacrylate Ligand, for Nanocrystal Stabilization and Covalent
Bonding into the Acrylate Cure Matrix
##STR00017##
[0250] General:
[0251] The reagents and solvents were purchased from Aldrich and
used without further purification. However, the amine/carboxylic
acid were stored under CDA. The reagent handling and reaction were
performed under clean dry air (CDA), as noted. FTIR analysis was
obtained on a Nicolet 6700 spectrometer equipped with a Smart iTR
Attenuated Total Reflectance (ATR) Sampling Accessory. Mass
spectroscopy analysis was obtained by Scripps MS Center for
Metabolomics and Mass Spectrometry.
[0252] Synthetic Procedure:
[0253] To a 20 mL amber vial was added 11-aminoundecanoic acid
(1.19 g, 5.91 mmoles) that was then dissolved in methanol (5 mL) to
form a slurry. The vial was closed with a septum cap. Then into a
separate vial was added trimethylolpropane trimethacrylate (1.00 g,
2.95 mmoles) that was dissolved in methanol (5 mL) to produce a
clear, colorless solution that was drawn into a syringe. Under CDA,
the amine solution then was added to the acrylate solution dropwise
over 5 min. The reaction solution remained an opaque, white slurry.
The solution was stirred at room temperature under CDA overnight.
Samples were removed about 30 min after addition, and overnight,
and the volatiles were removed with flowing nitrogen gas and vacuum
to prepare them for FTIR analysis. FTIR analysis of the two samples
was essentially the same, except the hydrogen bonding regions
between 2500 cm.sup.-1 and 3500 cm.sup.-1 were not the same. The
product was isolated by adding toluene (5 mL) and, after mixing,
the volatiles were removed with flowing nitrogen gas followed by
vacuum overnight. The product was an opaque, white semi-solid.
[0254] Analytical:
[0255] Trimethylolpropane trimethacrylate FTIR (diamond,
cm.sup.-1): 1715 (s, C.dbd.O).
[0256] Product FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad w,
hydrogen bonded carboxylic acid), 1718 (m, C.dbd.O), 1637 (m,
C.dbd.C).
[0257] ESI TOF MS: m/z (% relative intensity, ion): Positive 540
(40%, M-2(CH.sub.2).sub.4CO.sub.2H+), 361 (45%,
M-C(O)C(CH.sub.3).dbd.CH.sub.2 and --(CH.sub.2).sub.7CO.sub.2H and
--(CH.sub.2).sub.8CO.sub.2H.sup.-), 356 (100%,
M-C(O)C(CH.sub.3)CH.sub.2NH(CH.sub.2).sub.11CO.sub.2H and
--(CH.sub.2).sub.5CO.sub.2H.sup.-) and Negative 641 (45%,
M-CH.sub.2CO.sub.2C(CH.sub.3).dbd.CH.sub.2.sup.-), 501 (35%,
M-C(CH.sub.3)CH.sub.2NH(CH.sub.2).sub.10CO.sub.2H--), 346 (55%,
M-CH.sub.2CO.sub.2C(CH.sub.3).dbd.CH.sub.2 and
(CH.sub.2).sub.9CO.sub.2H and (CH.sub.2).sub.8CO.sub.2H.sup.-).
[0258] C. Synthesis of DCA7MA, a Bidentate Dicarboxylic Acid, from
a Dicarboxylic Acid Amine and Hexanediol Dimethacrylate
##STR00018##
[0259] General:
[0260] The reagents and solvents were purchased from Aldrich and
used without further purification. The starting materials
dicarboxylic acid amine (DCA10A) was stored and handled in the
glove box and hexanediol dimethacrylate was stored and handled in
the air. However, the hexanediol dimethacrylate was also combined
with 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) to prevent
polymerization. To a 20 mL vial was added hexanediol dimethacrylate
(10 g, 39.3 mmoles) followed by TEMPO (14.2 mg) in air, and the
solution in the vial was mixed with a vial rolling mixer overnight
to completely dissolve the TEMPO and produce a clear solution.
Toluene and methanol were also stored and handled under nitrogen
gas. FTIR analysis was obtained on a Nicolet 6700 spectrometer
equipped with a Smart iTR Attenuated Total Reflectance (ATR)
Sampling Accessory. Mass spectroscopy analysis was obtained by
Scripps MS Center for Metabolomics and Mass Spectrometry.
[0261] Synthesis of the Anhydride:
[0262] To a 20 mL clear glass vial was added hexanediol diacrylate
(0.867 g, 3.41 mmoles), which was dissolved in methanol (2.0 mL).
The vial then was capped with a septum cap, attached to the vacuum
line with a needle through the septum, and placed into a heat block
that was thermostat controlled at 30.degree. C. The diacid amine
(DCA10A) (1.18 g, 3.41 mmoles) was dissolved in methanol (8.7 mL).
The solution was drawn into a syringe and added dropwise over 10
min with stirring. The reaction solution was clear after the
addition, and remained clear upon stirring at 30.degree. C.
overnight. A sample was removed, and the volatiles were removed
with flowing nitrogen gas and vacuum to prepare them for FTIR
analysis. FTIR analysis showed two C.dbd.O peaks at 1701 cm.sup.-1
and 1636 cm.sup.-1, which are different than the peaks that
occurred when the solution was the placed under starting
diacid-amine at 1712 cm.sup.-1 and 1633 cm.sup.-1 and the
hexanediol dimethacrylate at 1713 cm.sup.-1. As a result, the
reaction was considered complete, and the volatiles were removed
with flowing nitrogen gas followed by vacuum. The product was
stored in methanol for the next reaction. The purity and yield of
this synthesis may be improved with a tertiary amine catalyst such
as trimethylamine or pyridine.
[0263] Analytical Data:
[0264] FTIR (diamond, cm.sup.-1): 3275 (m, amine), 3069 (w, olefin
C--H), 1701 (m, C.dbd.O), 1636 (m, C.dbd.O).
[0265] ESI TOF MS: m/z (% relative intensity, ion): Positive 266
(25%,
M-2HO.sub.2C(CH.sub.2).sub.2--CH.sub.3CH(CH.sub.2)CO(O)(CH.sub.2).sub.6OC-
(O)CH.sub.2CH.sub.3+Na+H), 447 (50%,
M-CH.sub.3C(CH.sub.2)CO(O)(CH.sub.2).sub.5+H), negative 445 (100%,
M-CH.sub.3C(CH.sub.2)CO(O)(CH.sub.2).sub.5--H).
[0266] D. Synthesis of DCA2MI, DCA4MI and DCA8MI, that are
Bidentate Dicarboxylic Acid, from a Dicarboxylic Acid Amine and the
Amine-Maleimides A2MI, A4MI and A8MI, Respectively
##STR00019##
[0267] General:
[0268] The reagents and solvents were purchased from Aldrich and
used without further purification. The starting materials
dicarboxylic acid-methacrylate (DSA7MA) was stored in methanol in
the glove box along with the maleimide-amine that was stored as a
dry powder. Toluene and methanol were also stored and handled under
nitrogen gas. FTIR analysis was obtained on a Nicolet 6700
spectrometer equipped with a Smart iTR Attenuated Total Reflectance
(ATR) Sampling Accessory. Mass spectroscopy analysis was obtained
by Scripps MS Center for Metabolomics and Mass Spectrometry.
[0269] Synthesis of DCA8MI with n=8:
[0270] To an 8 mL clear glass vial was added maleimide-amine (A8MI)
(0.100 g, 0.446 mmoles), and the diacid-methacrylate (DSA7MA)
(0.268 g, 0.446 mmoles) was added in methanol (1.6 mL). The vial
was then stirred over the weekend while resting in a heat block
that was temperature controlled at 30.degree. C. The volatiles then
were removed with flowing nitrogen gas followed by vacuum, leaving
the product a white, oily paste.
[0271] Analytical Data:
[0272] FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad, carboxylic
acid OH), 3273 (w, amine), 3059 (w, olefin C--H), 1967 (m,
C.dbd.O), 1636 (s, C.dbd.O).
[0273] ESI TOF MS: m/z (% relative intensity, ion): Positive 447
(50%,
M-(HOC(O)CH.sub.2CH.sub.2C(O)NHCH.sub.2CH.sub.2).sub.2N(CH.sub.2).sub.2NH-
CH.sub.2CH(CH.sub.3)+Li+H) and negative 445 (100%,
M-(HOC(O)(CH.sub.2).sub.2C(O)NHCH.sub.2CH.sub.2).sub.2N(CH.sub.2).sub.2NH-
CH.sub.2CH(CH.sub.3)+Li-H), 427 (15%,
M-(HOC(O)(CH.sub.2).sub.2C(O)NHCH.sub.2CH.sub.2).sub.2N)CH.sub.2).sub.2NH-
CH.sub.2CH(CH.sub.3)C(O)O.+-.H.sub.2O--H) and 459 (15%,
M-(HOC(O)(CH.sub.2).sub.2C(O)NHCH.sub.2CH.sub.2).sub.2N-Maleimide+Li+Na+H-
).
The other products were synthesized similarly.
[0274] For DCA2MI the n=2 derivative: dicarboxylic
acid-methacrylate (0.428 g, 0.713 mmoles) in 2.2 mL methanol was
combined with maleimide-amine (A2MI) (0.100 g, 0.713 mmoles).
[0275] FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad, carboxylic
acid OH), 3268 (m, amine), 3068 (m, olefin), 1702 (m, C.dbd.O), and
1635 (s, C.dbd.O).
[0276] ESI TOF MS: m/z (% relative intensity, ion): Positive 429
(20%,
M-(HOC(O)CH.sub.2CH.sub.2C(O)NHCH.sub.2CH.sub.2).sub.2NCH.sub.2CH.sub.2+H-
.sub.2O) and 447 (55%,
M-(HOC(O)CH.sub.2CH.sub.2C(O)NHCH.sub.2CH.sub.2).sub.2N+Li+H) and
negative 691 (15%, M-maleimide+2Na--H) and 445 (100%,
M-(HOC(O)CH.sub.2CH.sub.2C(O)NHCH.sub.2CH.sub.2).sub.2N+Li-H).
[0277] For DCA4MI the n=4 derivative: dicarboxylic
acid-methacrylate (0.357 g, 0.594 mmoles) in 1.8 mL methanol was
combined with maleimide-amine (A4MI) (0.100 g, 0.594 mmoles).
[0278] FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad, carboxylic
acid OH), 3265 (m, amine), 3075 (m, olefin), 1695 (m, C.dbd.O), and
1634 (s, C.dbd.O).
[0279] ESI TOF MS: m/z (% relative intensity, ion): Positive 693
(10%, M-maleimideCH.sub.2CH.sub.2+2Na+H) and 593 (10%,
M-maleimideCH.sub.2--HOC(O)CH.sub.2CH.sub.2--H+Li) and negative 459
(10%,
M-maleimide-CH.sub.2CH.sub.2CH.sub.2CH.sub.2NHCH.sub.2CH(CH.sub.3)CO(O)CH-
.sub.2CH.sub.2CH.sub.2CH.sub.2--H) and 691 (10%,
M-maleimideCH.sub.2CH.sub.2+2Na--H).
TABLE-US-00004 TABLE 3 Succinic Acid Ligand Structure
Guide--Polymerizable End Groups Meth (Meth) (Acrylate) Maleimide
Acrylate Ligand Maleimide Ligand Ligand Length, Ligand Length, in
Density Name in atoms Name atoms Tetradentate SA16MA 15 SA2MI 23
SA4MI 25 SA8MI 29 SA2D2AMI 26 DSA12MA 13 DSA2MI 19 DSA4MI 21 DSA8MI
25 DSA2AMI 22
[0280] E. Synthesis of SA16MA, a Bidentate Dicarboxylic Acid, from
a Mercaptosuccinic Acid and Hexanediol Dimethacrylate
##STR00020##
[0281] General:
[0282] The reagents and solvents were purchased from Aldrich and
used without further purification. The starting materials
mercaptosuccinic acid was stored and handled in the glove box while
hexanediol dimethacrylate was stored and handled in the air.
However, the hexanediol dimethacrylate was also combined with TEMPO
to prevent polymerization. To a 20 mL vial was added hexanediol
dimethacrylate (10 g, 39.3 mmoles) followed by TEMPO (14.2 mg) in
air, and the solution was mixed with a rolling vial mixer overnight
to completely dissolve the TEMPO and produce a clear solution.
Toluene and methanol were also stored and handled under nitrogen
gas. FTIR analysis was obtained on a Nicolet 6700 spectrometer
equipped with a Smart iTR Attenuated Total Reflectance (ATR)
Sampling Accessory. Mass spectroscopy analysis was obtained by
Scripps MS Center for Metabolomics and Mass Spectrometry.
[0283] Synthesis of the Anhydride:
[0284] To a 20 mL clear glass vial were added mercaptosuccinic acid
(2.00 g, 13.3 mmoles) and methanol (7.0 mL) in the glove box. The
thiol was dissolved completely and pulled into a syringe. The
hexanediol dimethacrylate (3.39 g, 13.3 mmoles) was transferred
into a 20 mL brown glass vial in air and then de-gassed in the
antechamber on the way into the glove box. Once inside the glove
box, the hexanediol dimethacrylate was dissolved in methanol (4.0
mL) and the vial was capped with a septum cap. Outside the glove
box, the vial was attached to the vacuum line using a syringe
needle through the septum. The vial was placed into a
thermostat-controlled heat block maintained at 30.degree. C., and
the solution of the thiol was added dropwise over 10 min. Following
this addition, the reaction solution was clear, and was then heated
at 40.degree. C. overnight. After being heated overnight, the
reaction solution was opaque, but stirring freely. The solution was
sampled, and the volatiles were removed from the sample with
flowing nitrogen gas followed by vacuum. FTIR analysis of the
sample showed C.dbd.O peaks at 1690 cm.sup.-1, which were different
than those obtained with the mercaptosuccinic acid at 1681
cm.sup.-1, but not very much different than those obtained with
hexanediol dimethacrylate at 1713 cm-1. However, the volatiles were
removed from the reaction solution with flowing nitrogen gas
followed by vacuum, leaving an oily paste. The reaction procedure
can be improved by adding 0.01 eq (or less) of a catalytic amine
such as triethyl amine or pyridine.
[0285] Analytical Data:
[0286] FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad, carboxylic
acid) and 1710 (m, C.dbd.O).
[0287] ESI TOF MS: m/z (% relative intensity, ion): Positive 255
(100%,
M-CO.sub.2H--(CH.sub.2).sub.4OC(O)CH(CH.sub.2)CH.sub.3+2H.sub.2O),
255 (100%,
M-CO.sub.2H--(CH.sub.2).sub.4OC(O)CH(CH.sub.2)CH.sub.3+2H.sub.2O),
271 (50%,
M-CO.sub.2H--(CH.sub.2).sub.2OC(O)(CH.sub.2)CH.sub.3)+Na), 266
(25%, M-(CH.sub.2).sub.4OC(O)C(CH.sub.2)CH.sub.3) and 277 (25%,
M-(CH.sub.2).sub.3OC(O)C(CH.sub.2)CH.sub.3).
[0288] F. Synthesis of SA2MI, a Bidentate Dicarboxylic Acid, from a
Dicarboxylic Acid Amine and Hexanediol Dimethacrylate
##STR00021##
[0289] General:
[0290] The reagents and solvents were purchased from Aldrich and
used without further purification. The starting material,
dicarboxylic acid-methacrylate (SA16MA), was stored in methanol in
the glove box. The maleimide-amine was stored as a dry powder in
the glove box. Toluene and methanol were also stored and handled
under nitrogen gas. FTIR analysis was obtained on a Nicolet 6700
spectrometer equipped with a Smart iTR Attenuated Total Reflectance
(ATR) Sampling Accessory. Mass spectroscopy analysis was obtained
by Scripps Center for Metabolomics and Mass Spectrometry.
[0291] Synthesis of SA2MI, the product with n=2:
[0292] To an 8 mL clear glass vial was added maleimide-amine (A2MI)
(0.100 g, 0.713 mmoles), and diacid-methacrylate (SA16MA) (0.289 g,
0.713 mmoles) was added in methanol (1.0 mL). The vial was then
stirred over the weekend while resting in a heat block that was
temperature controlled at 30.degree. C. The volatiles then were
removed with flowing nitrogen gas followed by vacuum, leaving the
product was a white oily paste.
[0293] Analytical Data:
[0294] FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad, carboxylic
acid OH) and 1702 (s, C.dbd.O).
[0295] ESI TOF MS: m/z (% relative intensity, ion): Positive 209
(100%,
M-HO.sub.2CCH.sub.2CH(CO.sub.2H)SCH.sub.2CH(CH.sub.3)C(.dbd.O)O(CH.sub.2)-
6O--H--), 255 (35%,
M-HO.sub.2CCH.sub.2CH(CO.sub.2H)SCH.sub.2CH(CH.sub.3)C(.dbd.O)O(CH.sub.2)-
.sub.5+H) and 463 (25%, M-HO.sub.2C--HO.sub.2C+Li) and negative 403
(20%,
M-HO.sub.2CCH.sub.2CH(CO.sub.2H)SCH.sub.2CH(CH.sub.3)--H+2H.sub.2O).
The other products were synthesized similarly.
[0296] For SA4MA, the n=4 derivative: dicarboxylic
acid-methacrylate (0.241 g, 0.594 mmoles) in 1.5 mL methanol was
combined with maleimide-amine (A4MI) (0.100 g, 0.594 mmoles).
[0297] FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad, carboxylic
acid OH) and 1711 (s, C.dbd.O).
[0298] For SA8MA, the n=8 derivative: dicarboxylic
acid-methacrylate (0.181 g, 0.466 mmoles) in 1.5 mL methanol was
combined with maleimide-amine (A8MI) (0.100 g, 0.446 mmoles).
[0299] FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad, carboxylic
acid OH) and 1697 (s, C.dbd.O).
[0300] G. Synthesis of DSA12MA, a Tetradentate Succinic Acid, from
a Mercaptosuccinic Acid and TMPTMA
##STR00022##
[0301] General:
[0302] The reagents and solvents were purchased from Aldrich and
used without further purification. The starting material,
mercaptosuccinic acid, was stored and handled in the glove box,
while trimethylolpropane trimethacrylate (TMP TMA) was stored and
handled in the air. However, the TMP TMA was also combined with
TEMPO to prevent polymerization. To a 20 mL vial was added TMP TMA
(10 g, 29.6 mmoles) followed by TEMPO (10.5 mg) in air, and the
solution was mixed with a rolling vial mixer overnight to
completely dissolve the TEMPO and produce a clear solution. Toluene
and methanol were also stored and handled under nitrogen gas. FTIR
analysis was obtained on a Nicolet 6700 spectrometer equipped with
a Smart iTR Attenuated Total Reflectance (ATR) Sampling Accessory.
Mass spectroscopy analysis was obtained by Scripps MS Center for
Metabolomics and Mass Spectrometry.
[0303] Synthesis of DSA12MA:
[0304] To a 20 mL clear glass vial was added mercaptosuccinic acid
(2.66 g, 17.7 mmoles) and methanol (9.0 mL) in the glove box. The
thiol then was dissolved completely and pulled into a syringe. The
TMP TMA (3.00 g, 8.86 mmoles) was transferred into a 20 mL brown
glass vial in air and then de-gassed in the antechamber on the way
into the glove box. Once inside, the TMP TMA was dissolved in
methanol (4.0 mL) and the vial was capped with a septum cap.
Outside the glove box, the vial was attached to the vacuum line
using a syringe needle through the septum. The vial was placed into
a thermostat-controlled heat block maintained at 30.degree. C., and
the solution of the thiol was added dropwise over 10 min. After
addition, the reaction solution was clear and was then heated at
40.degree. C. overnight. After being heated overnight, the reaction
solution was opaque but stirring freely. The solution was sampled,
and the volatiles were removed from the sample with flowing
nitrogen gas followed by vacuum. FTIR analysis of the sample showed
C.dbd.O peaks at 1689 cm.sup.-1, which were different than TMP TMA
at 1715 cm.sup.-1, but not very much different than the
mercaptosuccinic acid at 1681 cm.sup.-1. The reaction ceased, and
the product was stored in methanol in the glove box. This reaction
procedure can be improved by adding 0.01 eq (or less) of a
catalytic amine such as triethyl amine or pyridine.
[0305] Analytical Data:
[0306] FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad, carboxylic
acid) and 1689 (s, C.dbd.O).
[0307] ESI TOF MS: m/z (% relative intensity, ion): Positive 361
(60%,
M-CH.sub.3C(CH.sub.2)CO(O)--HO.sub.2CCH.sub.2CH(CO.sub.2H)SCH.sub.2CH(CH.-
sub.3)CO(O)+H.sub.2O+Na), 511 (75%,
M-CO.sub.2H--CH.sub.3C(CH.sub.2)CO(O)), 525 (20%,
M-HO.sub.2CCH.sub.2CHCO.sub.2H+H), 525 (20%,
M-CO.sub.2H--CH.sub.3C(CH.sub.2)C(O)--H).
[0308] H. Synthesis of DSA2MI, DSA4MI and DCS8MI, that are
Bidentate Dicarboxylic Acids, from a Dicarboxylic Acid Amine and
the Amine-Maleimides A2MI, A4MI and A8MI, Respectively
##STR00023##
[0309] General:
[0310] The reagents and solvents were purchased from Aldrich and
used without further purification. The starting material
dicarboxylic acid-methacrylate (DSA12MA) was stored in methanol in
the glove box. Maleimide amine was stored as a dry powder. Methanol
was also stored and handled under nitrogen gas. FTIR analysis was
obtained on a Nicolet 6700 spectrometer equipped with a Smart iTR
Attenuated Total Reflectance (ATR) Sampling Accessory. Mass
spectroscopy analysis was obtained by Scripps MS Center for
Metabolomics and Mass Spectrometry.
[0311] Synthesis of DSA2MI with n=2:
[0312] To an 8 mL clear glass vial was added maleimide-amine (A2MI)
(0.100 g, 0.713 mmoles), and the tetraacid-methacrylate (DSA12MA)
(0.456 g, 0.713 mmoles) was added in methanol (1.6 mL). The vial
was then stirred over the weekend while resting in a heat block
that was temperature controlled at 30.degree. C. The volatiles then
were removed with flowing nitrogen gas followed by vacuum, leaving
the product a white oily paste.
[0313] Analytical Data:
[0314] FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad, carboxylic
acid OH) and 1700 (s, C.dbd.O).
[0315] ESI TOF MS: m/z (% relative intensity, ion): Positive 359
(15%,
M-2H.sub.02CCH.sub.2CH(CO.sub.2H)SCH.sub.2CH(CH.sub.3)C(.dbd.O)+H.sub.2O--
-H), 459 (10%,
M-HO.sub.2CCH.sub.2CH(CO.sub.2H)--HO.sub.2CCH.sub.2CH(CO.sub.2H)SCH.sub.2-
CH(CH.sub.3)C(.dbd.O)+2Li--H), 565 (10%,
M-HO.sub.2CCH.sub.2CH(CO.sub.2H)SCH.sub.2CH(CH.sub.3)C(.dbd.O)--H+Li)
and 697 (10%, M-2HO.sub.2C+Li), negative 487 (10%,
M-HO.sub.2CCH.sub.2CH(CO.sub.2H)--HO.sub.2CCH.sub.2CH(CO.sub.2H)SCH.sub.2-
CH(CH.sub.3)C(.dbd.O)--H) and 637 (10%,
M-HO.sub.2CCH.sub.2CH(CO.sub.2H)S+Li-H).
The other products were synthesized similarly.
[0316] For DSA4MI the n=4 derivative: tetracarboxylic
acid-methacrylate (A4MI) (0.380 g, 0.594 mmoles) in 1.3 mL methanol
was combined with maleimide-amine (0.100 g, 0.594 mmoles)
[0317] FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad, carboxylic
acid OH), 3075 (w, olefin) and 1699 (s, C.dbd.O).
[0318] For DSA8MI the n=8 derivative: tetracarboxylic
acid-methacrylate (0.268 g, 0.446 mmoles) in 1.0 mL methanol was
combined with maleimide-amine (A8MI) (0.100 g, 0.446 mmoles).
[0319] FTIR (diamond, cm.sup.-1): 3500 to 2500 (broad, carboxylic
acid OH) and 1696 (s, C.dbd.O).
Example 3: Ligand Exchange of Quantum Materials Green QDS with
Ligand EG4.3TSA
[0320] General:
[0321] The solvents dimethoxy ethane (DME), ethyl acetate (EtOAc),
hexanes and ethyl alcohol (EtOH) were purchased from Aldrich
(anhydrous grade) and used without further purification in a
glovebox. The ligand EG4.3TSA was synthesized as described in
Example 1. The diluent, M-600-MI, was synthesized as described in
Example 5. The QDs were purchased from Quantum Materials Corp in
San Marcos, Tex. An Amicon Ultra 4 (i.e. 4 mL volume) with high
flux polyethersulfone (PES) membrane with 30K molecular weight cut
off (MWCO) was used for centrifugal filtration. FTIR analysis was
obtained on a Nicolet 6700 spectrometer equipped with a Smart iTR
Attenuated Total Reflectance (ATR) Sampling Accessory. Analysis for
optical density (OD) was performed on a Cary 5000 UV-Vis
Spectrometer by Varian.
[0322] Procedure:
[0323] To six, 8 mL vials (synthesis performed in parallel) in the
glovebox were added EG4.3TSA ligand (200 mg, 0.502 mmoles, 1.4 eq
ligand/surface Zn atom (as shown in the table below) and DME (2.0
mL), and the reaction solution was gently swirled until clear. A
flea size magnetic stir bar then was added, followed by a solution
of green QDs in toluene (2.0 mL with [QD] of 10 OD.sub.450 measured
at 450 nm). After closing the vial with a screw cap, the mixture
was then heated in a thermostat-controlled heat block at 90.degree.
C. for 16 h. The reaction solution was clear green upon
combination, and was also clear green after being heated overnight
at 90.degree. C. The vial cap was replaced with a septum cap, and
the volatiles were removed with flowing nitrogen gas using two
syringe needles (nitrogen in and nitrogen out) to produce a clear,
concentrated oil. The oil was dissolved in EtOAc (200 .mu.L)
completely to form a clear solution, and the product was
precipitated with hexanes (2.0 mL). After the addition of hexane,
the vial was shaken aggressively for about 60 seconds and then
centrifuged using an angular velocity, .omega., of 2000 for 10
minutes to produce a clear, intensely green pellet underneath a
clear, colorless liquid supernatant. In the glove box the
supernatant was removed and discarded before the
dissolution/precipitation process was repeated again with EtOAc 200
.mu.L, precipitated with 2 mL of hexanes, mixed by shaking,
centrifuged, and the supernatant removed to produce an intensely
green pellet that was a little smaller in volume and a little
thicker in viscosity than produced by the first precipitation. The
product in each vial was dissolved in EtOH (1.0 mL) to a produce
clear, green solution. At the same time, one Amicon Ultra 4 filter
was cleaned with EtOH (4 mL) and centrifuged for 10 min to remove
surfactant from the filter membrane. The solution from four vials
then was added to the MWCO centrifuge filters, and the centrifuge
filters were spun at an angular velocity, .omega., of 2000 until
about 300 .mu.L of solution remained above the filter element.
During centrifugation, a small amount of green QDs leaked through
the filter, but the vast majority were retained. The retained QDs
had been concentrated into a yellow orange oil that could be
observed by the eye above the MWCO filter element. The last two
vials then were added to the filter, and the solution above the
filter was mixed by `pumping` the solution with a Pasteur pipette.
The filter was spun on the centrifuge until about 500 .mu.L of
solution remained above the filter element. Each vial then was
rinsed with EtOH, 1 mL, and that solution was added to the filter
sequentially and the vials were spun on the centrifuge with enough
EtOH so that each vial was rinsed with 2.times.1.0 mL EtOH. When
the volume in the centrifuge filter was about 500 .mu.L the
solution was transferred to a tared vial and the volatiles were
removed with flowing nitrogen gas to leave a concentrated paste of
quantum dot concentrate or `QD concentrate.` The vial was sent into
the glove box and the product was placed under vacuum in the
antechamber for 1 minute before weighing. The product was an
intensely green grease that weighed 94.4 mg. It was easily
dissolved in 1.0 mL EtOH, and a 20 .mu.L sample was dissolved in
4.0 mL EtOH for an optical density (OD) measurement at 450 nm using
a cuvette with 10 mm path length. Using the optical density from
this dilute solution measurement the OD.sub.450 was projected back
to the QD concentrate. The OD.sub.450 was 0.521, which made the
EtOH solution 105 OD.sub.450 and the QD concentrate 1214
OD.sub.450. While dissolved in 1 mL of EtOH, 100 mg of M-600-MI
then was added, and the volatiles were removed with flowing
nitrogen gas followed by vacuum to leave a thick, intensely green,
but flowing oil. The table below summarizes some of the numbers
used in this synthesis.
TABLE-US-00005 Ratio; Zn mmoles OD450 of QD Zn atoms on Amount
mmoles ligand to QDs from solution surface surface Ligand/ of
ligand of ligand mmoles manu- used atoms/ in fwt of added to added
to Zn on QD facturer per vial OD450 solution ligand exchange
exchange surface 10 2 mL 1.79 .times. 0.179 EG4.3T 100 mg 0.251
1.40 10E-2 mmoles SA/ mmoles mmoles/ 398.47 OD450
Example 4: Ligand Exchange of Quantum Materials Red QDS with Ligand
EG4.3TSA
[0324] General:
[0325] The solvents dimethoxy ethane (DME), ethyl acetate (EtOAc),
hexanes and ethyl alcohol (EtOH) were purchased from Aldrich
(anhydrous grade) and used without further purification in a
glovebox. The ligand EG4.3TSA was synthesized as described in
Example 1. The diluent, M-600-MI, was synthesized as described in
Example 5. The QDs were purchased from Quantum Materials Corp in
San Marcos, Tex. An Amicon Ultra 4 (i.e. 4 mL volume) with high
flux polyethersulfone (PES) membrane with 30K molecular weight cut
off (MWCO) was also used for centrifugal filtration. FTIR analysis
was obtained on a Nicolet 6700 spectrometer equipped with a Smart
iTR Attenuated Total Reflectance (ATR) Sampling Accessory. Analysis
for optical density (OD) was performed on a Cary 5000 UV-Vis
Spectrometer by Varian.
[0326] Procedure:
[0327] To six, 8 mL vials (synthesis performed in parallel) in the
glovebox were added EG4.3TSA ligand (40 mg, 0.502 mmoles, 1.4 eq
ligand/surface Zn atom, as shown in the table below) and DME (2.0
mL), and the reaction solution was gently swirled until clear. Then
a flea size magnetic stir bar was added, followed by a solution of
red QDs in toluene (2.0 mL with [QD] of 10 OD measured at 450 nm).
After closing the vial with a screw cap, the mixture was then
heated in a thermostat-controlled heat block at 90.degree. C. for
16 h. The reaction solution was clear red upon combination and was
also clear red after heating at 90.degree. C. overnight. The vail
cap was replaced with a septum cap, and the volatiles were removed
with flowing nitrogen gas using two syringe needles (nitrogen in
and nitrogen out) to produce a clear concentrated oil. The oil was
dissolved in EtOAc (100 .mu.L) completely to form a clear solution,
and the product was precipitated by the addition of hexanes (2.0
mL). After hexane addition, the vial was shaken aggressively for
about 60 seconds and then centrifuged using an angular velocity,
.omega., of 2000 for 10 minutes to produce a clear, intensely red
pellet underneath a clear, colorless liquid supernatant. In the
glove box, the supernatant was removed and discarded before the
dissolution/precipitation process was repeated with EtOAc 200
.mu.L, precipitated with hexanes 2 mL, mixed by shaking,
centrifuged and the supernatant removed to produce an intensely red
pellet that was a little smaller in volume and a little thicker in
viscosity than produced by the first precipitation. The product in
each vial was dissolved in EtOH (1.0 mL) to produce a clear, red
solution. At the same time, one Amicon Ultra 4 filter was cleaned
with EtOH (4 mL) and centrifuged for 10 min to remove surfactant
from the filter membrane. The solution from four vials was then
added to the MWCO centrifuge filters, and the centrifuge filters
were spun at an angular velocity, .omega., of 2000 until about 300
.mu.L of solution remained above the filter element. During
centrifugation, a small amount of red QDs leaked through the
filter, but the vast majority were retained. The retained QDs had
been concentrated into a dark red oil that could be observed by the
eye above the MWCO filter element. The last two vials then were
added to the filter, and the solution above the filter was mixed by
`pumping` the solution with a Pasteur pipette. The filter was spun
on the centrifuge until about 500 .mu.L of solution remained above
the filter element. Each vial then was rinsed with EtOH, 1 mL, that
solution added to the filter sequentially, and the vials were spun
on the centrifuge with enough EtOH so that each vial was rinsed
with 2.times.1.0 mL EtOH. When the volume in the centrifuge filter
was about 500 .mu.L the solution was transferred to a tared vial
and the volatiles were removed with flowing nitrogen gas to leave a
concentrated paste of quantum dot concentrate or `QD concentrate.`
The vial was sent into the glove box, and the product was placed
under vacuum in the antechamber for 1 minute before weighing. The
product was an intensely red grease that weighed 17.3 mg. It was
easily dissolved in 1.0 mL EtOH and a 20 .mu.L sample was dissolved
in 4.0 mL EtOH for an optical density (OD) measurement at 450 nm
using a cuvette with 10 mm path length. Using the optical density
from this dilute solution measurement, the OD.sub.450 was projected
back to the QD concentrate. The OD.sub.450 was 0.310, which made
the EtOH solution 62.3 OD.sub.450 and the QD concentrate 3664
OD.sub.450. While dissolved in 1 mL of EtOH, 200 mg of M-600-MI was
then added, and the volatiles were removed with flowing nitrogen
gas followed by vacuum to leave a thick, intensely red grease. The
table below summarizes some of the numbers used in this
synthesis.
TABLE-US-00006 Ratio; OD450 Zn mmoles of QDs QD450 Zn atoms on
Amount mmoles ligand to from solution surface surface Ligand/ of
ligand of ligand mmoles manu- used atoms/ in fwt of added to added
to Zn on QD facturer per vial OD450 solution ligand exchange
exchange surface 12.6 2.0 mL 1.99 .times. 0.0501 EG4.3T 40.0 mg
0.304 2.0 10E-3 mmoles SA/ mmoles/ 398.47 OD450
Example 5: Synthesis of M-600-MI from Jeffamine M-600
##STR00024##
[0329] General:
[0330] The reagents and solvents were purchased from Aldrich and
used without further purification. The M-600 Jeffamine was obtained
from Huntsman Reagent handling and the reaction were performed
under nitrogen, except where noted. FTIR analysis was obtained on a
Nicolet 6700 spectrometer equipped with a Smart iTR Attenuated
Total Reflectance (ATR) Sampling Accessory. Mass spectroscopy
analysis was obtained by Scripps MS Center for Metabolomics and
Mass Spectrometry.
[0331] Synthetic Procedure:
[0332] To a 20 mL clear glass vial was added
exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride (2.76 g, 16.7
mmoles) in air, and the vial was sent into the glove box open to
de-gas in the antechamber. 20 mL of acetonitrile was then added,
and the solution was stirred for about 15 minutes until dissolved.
The solution was drawn into a 24 mL syringe. Concurrently, to a 40
mL vial was added Jeffamine M-600 (10.0 g, 16.7 mmoles) in air. The
vial was then capped with a septum cap and gently purged with
nitrogen gas for 15 minutes before de-gassed water, 5 mL, was added
to form a clear, colorless solution. While a nitrogen atmosphere
was maintained with a needle and bubbler, the reaction solution was
heated in a thermostat-controlled heat block to 50.degree. C. The
solution of the anhydride in acetonitrile was then added dropwise
over 15 minutes. The reaction was stirred at 50.degree. C. for 16 h
(or overnight) under nitrogen.
[0333] Following heating the reaction solution overnight, a 100
.mu.L sample was placed under vacuum at a pressure of less than 100
mtorr and analyzed by FTIR. There were two new peaks at 1717
cm.sup.-1 and 1578 cm.sup.-1 for maleimide C.dbd.O, which differed
from the starting anhydride peaks at 1857 cm.sup.-1 and 1778
cm.sup.-1. The Jeffamine also did not have significant absorbances
in this region. The volatiles were removed from the product by
flowing nitrogen gas, while the vial was in the
thermostat-controlled heat block was maintained at 50.degree. C.
Once the volume of the solution had been reduced by half, toluene
was added (24 mL), the reaction solution was thoroughly mixed, and
the volatiles were removed again with flowing nitrogen gas. Toluene
(24 mL) was added, and the volatiles were removed again with the
same procedure. The reaction vial was then placed into a desiccator
and subjected to vacuum overnight with magnetic stirring. Following
that, the whole process was performed again: toluene 24 mL, flowing
nitrogen, toluene 24 mL, flowing nitrogen, and vacuum with
stirring. When the process was completed the pressure in the
desiccator was <100 mtorr.
[0334] The product was analyzed by FTIR after the first and second
vacuum procedures. The baseline was compared between .about.3800
and .about.2200 cm.sup.-1 as a relative measure of the amount of
water in the mixture. The relative shape and size of the baseline
and the shoulder surrounding the sp.sup.3 C.dbd.H bond stretch was
the same, so the product was considered dry and the toluene was
removed.
[0335] Analytical:
[0336] Product FTIR (diamond, cm.sup.-1): 3078 (sh, olefin C--H),
1720 (w, maleimide C.dbd.O) & 1634 (w, maleimide C.dbd.O) symm
and asymm.
Example 6: Formulation of an Acrylate Cure, Thin Film of Green or
Red QD Phosphors Exchanged with EG4.3TSA Ligand and Diluent
M-600-MI
[0337] In this example, green or red QD phosphors exchanged with
EG4.3TSA ligand and dissolved in diluent M-600-MI were dissolved in
ether methacrylates and then thin film coated at 10 .mu.m
thickness, followed by free radical curing.
[0338] The preparation of QD phosphors exchanged with EG4.3TSA
ligand and dissolved in diluent M-600-MI was described in Examples
3 and 4. The QD phosphor/ligand/diluent mixture was efficiently
dissolved in ether methacrylate monomers, as described below. This
procedure describes the formulation of green QDs. The procedure for
red QDs is similar, and thus is also briefly presented, with
relevant data, at the end of this procedure. In total, the
procedure describes the fabrication of 10 .mu.m thick thin films of
green QD phosphors at 200, 300 & 400 mg/mL, and red QD
phosphors at 100 mg/mL.
[0339] General:
[0340] The ether methacrylates, ethylene glycol methyl ether
methacrylate (EGMEMA), di(ethylene glycol) methyl ether
methacrylate (DEGMEMA), and tetrahydrofurfuryl methacrylate (THFMA)
were purchased from Aldrich and used without purification. Ethyl
alcohol (EtOH) anhydrous and dimethoxyethane (DME) anhydrous were
also purchased from Aldrich and used without further purification.
Photoinitiator 2,4,6-trimethylbenzoyldiphenyl phosphine oxide or
`liquid TPO` was purchased from Omnirad and also used without
further purification. Optical density (OD) analysis was performed
on a Cary 5000 UV-Vis Spectrometer by Varian.
[0341] Procedure:
[0342] The procedure uses green QDs that have been ligand exchanged
with EG4.3TSA, purified by MWCO filtration then combined with
M-600-MI to form a `thick, intensely green, but flowing oil,` as
described in Example 3. The resulting oil was dissolved in EtOH, 1
mL, and transferred into three separate 8 mL vials. The volatiles
were then removed with flowing nitrogen gas (one needle for
nitrogen in & one needle to vent) to produce three samples with
roughly equal amounts as shown below.
TABLE-US-00007 Amount Amount of QD OD.sub.450 mg QDs/ Amount of QD
concen- of mL of of concentrate trate concen- concen- diluent with
diluent Reference isolated trate trate added isolated 10290-030AF
-31.5 mg 1214 4552 33 mg 78.4 mg 10290-030BF -31.5 mg 1214 4552 33
mg 69.7 mg 10290-030CF -31.5 mg 1214 4552 33 mg 66.2 mg
[0343] The oils were then combined with the methacrylates as shown
below and roller mixed to produce clear green solutions. .about.5
mg of the oils was then dissolved in DME, 4.0 mL, for OD.sub.450
analysis by UV-Vis spectroscopy. Analysis of the dilute sample was
projected to confirm the QD concentrate/diluent OD.sub.450.
TABLE-US-00008 Amount OD.sub.450 mg QDs/ of QD of QD mL of QD
Amount ligand/ ligand/ ligand/ of diluent/ diluent/ diluent/ meth-
meth- meth- meth- Methacrylate acrylate acrylate acrylate acrylate
Reference added added isolated mixture mixture 10290-030AF EGMEMA
~92 mg 169.0 mg 240 900 10290-030BF DEGMEMA ~92 mg 162.3 mg 195 731
10290-030CF THFMA ~92 mg 167.2 mg 208 780
[0344] The formulations then were diluted in methacrylates and
roller mixed to produce formulations with about 200 mg QDs/mL. To
cure the formulations photoinitiator, liquid TPO was added and the
formulations were roller mixed again. They remained clear green.
10-.mu.m-thick thin film samples were then fabricated using the
draw-down method and cured with UV light.
[0345] Notably, when the ink compositions of this example were
formulated using the same procedures and components, except that
the diluent was omitted, the QDs remained only sparingly soluble in
the ink compositions even after roller mixing the ink compositions
overnight.
TABLE-US-00009 Amount mg QDs/ of QD OD.sub.450 of mL of QD ligand/
QD ligand/ ligand/ Amount Ratio of diluent/ diluent/ diluent/ of
meth- diluent meth- meth- meth- Refer- acrylate to meth- acrylate
acrylate acrylate TPO-L ence added acrylate isolated mixture
mixture to add 10290- 520 mg 0.063 0.647 g 49.8 186.8 27.9 mg 030AF
10290- 376 mg 0.088 0.504 g 51.2 192 21.5 mg 030BF 10290- 604 mg
0.055 0.755 g 37.7 141 25.2 mg 030CF
[0346] Other formulations for concentrations of green QD phosphors
at 300 and 400 mg/mL or red QD phosphors at 100 mg/mL are described
below. They were ligand exchanged and purified analogously to other
procedures described herein. As described in this procedure, these
formulations started with QD phosphor/ligand/diluent data, as
tabulated in the table below.
TABLE-US-00010 Amount of QD Amount concen- of QD mg QDs/ Amount
trate concen- OD of mL of of with trate concen- concen- diluent
diluent Reference Color isolated trate trate added isolated
10290-033 Green 67.3 mg 1543 5786 70 mg 135.7 mg 10290-036 Green
64.3 mg 1451 5441 70 mg 137.0 mg 10290-037 Red 17.3 mg 3664 4228 20
mg 37.9 mg
[0347] The QD concentrates were combined with ether methacrylate,
EGMEMA, mixed by roller mixer, combined with photoinitiator liquid
TPO, draw-down coated at 10 .mu.m, and cured by UV light to produce
thin films on a glass substrate. Relevant data are described in the
table below.
TABLE-US-00011 Amount OD.sub.450 mg QDs/ of QD of QD mL of QD
Expected ligand/ ligand/ ligand/ mg QDs/ Amount Ratio of diluent/
diluent/ diluent/ mL in of meth- diluent meth- meth- meth- formu-
acrylate to meth- acrylate acrylate acrylate TPO-L Reference lation
added acrylate isolated mixture mixture to add 10290-033 300 1117
mg 0.063 1.237 g 79.2 297 54.8 mg 10290-036 400 738 mg 0.080 0.860
g 106 398 36.5 mg 10290-037 100 694 mg 0.029 0.710 g 84.4 97.4 30.5
mg
[0348] The table below tabulates emission data from the draw down
films. In the table, the reference indicates which ink composition
was used to make the film. All of the emission data were from
samples excited with a laser light source at 445 nm wavelength with
about 500 units of power. The photoluminescence intensity provides
a rough but qualitative measure of phosphor film brightness that
can be used to compare the brightness between these sample films.
The last column describing emission max shows that the phosphors
down converted the light energy of the emission and that the films
maintained their QD fluorescence. The OD roughly correlates to the
amount (in mg) of QDs in the films and the photoluminescence
roughly correlates to the amount (in mg) of QDs in the films.
Finally, the emission measurement for a dilute emission for the
green QDs was 547 nm, so a film emission of 549 to 550 nm indicates
that the QDs emission was not substantially shifted during the
ligand exchange/purification/formulation/film fabrication
processes.
TABLE-US-00012 Amount of Photolumi- QDs in mg nescence QDs/mL, from
Amount calculated excitation of QDs from OD at 445 nm Emis- in mg
measurement with about sion Refer- Meth- QDs/ in mg QDs/ 500 nits
max ence Color acrylate mL mL OD power in nm 10290- Green EGMEMA
200 187 0.0340 1260 550 030AF 10290- Green DEGMEMA 200 192 0.0634
1522 549 030BF 10290- Green THFMA 200 141 0.0307 1543 549 030CF
10290- Green EGMEMA 300 297 0.0515 2558 549 033 10290- Green EGMEMA
400 398 0.1271 5703 549 036 10290- Red EGMEMA 100 97 0.0608 1571
633 037
Example 7: Formulation, Characterization, and Inkjet Printing of
QD-Free Ink Compositions and Ink Compositions Containing Green or
Red QD Phosphors
[0349] In this example, the formulation of curable ink compositions
containing benzyl methacrylate as a base monomer is
illustrated.
[0350] Five printable ink compositions were formulated and
characterized. The first formulation did not contain quantum dots,
the second and third formulations contained red-emitting quantum
dots, and the fourth and fifth formulations contained
green-emitting quantum dots. The five formulations are shown in the
tables below.
[0351] QD-Free Curable Ink Composition
TABLE-US-00013 Commercial Source/Catalog Weight Percent Ink
Component Number (wt. %) Quantum Dots Nanosys QD Gen3 0 Benzyl
Methacrylate Aldrich/409448 90 Pentaerythritol Aldrich/408263 7
Tetracrylate TPO-L IGM/TPO-L 3 Total 100
[0352] First Red QD-Containing Curable Ink Composition
TABLE-US-00014 Commercial Source/Catalog Weight Percent Ink
Component Number (wt. %) Quantum Dots Nanosys QD Gen3 24.0 Red
Benzyl Methacrylate Aldrich/409448 68.4 Pentaerythritol
Aldrich/408263 5.32 Tetracrylate TPO-L IGM/TPO-L 2.28 Total 100
[0353] Second Red QD-Containing Curable Ink Composition
TABLE-US-00015 Commercial Source/Catalog Weight Percent Ink
Component Number (wt. %) Quantum Dots Nanosys QD Gen3 24.0 Red
Benzyl Methacrylate Aldrich/409448 73.72 TPO-L IGM/TPO-L 2.28 Total
100
[0354] First Green QD-Containing Curable Ink Composition
TABLE-US-00016 Commercial Source/Catalog Weight Percent Ink
Component Number (wt. %) Quantum Dots Nanosys QD Gen3 24.0 Green
Benzyl Methacrylate Aldrich/409448 68.4 Pentaerythritol
Aldrich/408263 5.32 Tetracrylate TPO-L IGM/TPO-L 2.28 Total 100
[0355] Second Green QD-Containing Curable Ink Composition
TABLE-US-00017 Commercial Source/Catalog Weight Percent Ink
Component Number (wt. %) Quantum Dots Nanosys QD Gen3 24.0 Green
Benzyl Methacrylate Aldrich/409448 73.72 TPO-L IGM/TPO-L 2.28 Total
100
[0356] The QD-Free Ink Composition had a viscosity of 3.4 cP and a
surface tension of 35 dyn/cm. The First Red QD-Containing Ink
Composition had a viscosity of 5.7 cP and a surface tension of 36
dyn/cm. The Second Red QD-Containing Ink Composition had a
viscosity of 6.5 cP and a surface tension of 36 dyn/cm. The First
Green QD-Containing Ink Composition had a viscosity of 5.8 cP and a
surface tension of 36. The viscosity and surface tension
measurements were made at temperatures between 21.degree. C. and
25.degree. C. Viscosities were measured using a Brookfield DV-1
viscometer and surface tensions were measured using a SITA
DynoTester Bubble Tensiometer.
[0357] The present teachings are intended to be illustrative, and
not restrictive. The Abstract is provided to comply with 37 C.F.R.
.sctn. 1.72(b), to allow the reader to quickly ascertain the nature
of the technical disclosure. It is submitted with the understanding
that it will not be used to interpret or limit the scope or meaning
of the claims. Also, in the above Detailed Description, various
features may be grouped together to streamline the disclosure. This
should not be interpreted as intending that an unclaimed disclosed
feature is essential to any claim. Rather, inventive subject matter
may lie in less than all features of a particular disclosed
embodiment. Thus, the following claims are hereby incorporated into
the Detailed Description as examples or embodiments, with each
claim standing on its own as a separate embodiment, and it is
contemplated that such embodiments can be combined with each other
in various combinations or permutations. The scope of the invention
should be determined with reference to the appended claims, along
with the full scope of equivalents to which such claims are
entitled.
* * * * *