U.S. patent application number 11/505324 was filed with the patent office on 2008-12-18 for photosensitive metal nanoparticle and method of forming conductive pattern using the same.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Eun Jeong Jeong, Sang Yoon Lee, Jong Jin Park.
Application Number | 20080311513 11/505324 |
Document ID | / |
Family ID | 33487922 |
Filed Date | 2008-12-18 |
United States Patent
Application |
20080311513 |
Kind Code |
A1 |
Park; Jong Jin ; et
al. |
December 18, 2008 |
PHOTOSENSITIVE METAL NANOPARTICLE AND METHOD OF FORMING CONDUCTIVE
PATTERN USING THE SAME
Abstract
A photosensitive metal nanoparticle and a method of forming a
conductive pattern using the same, wherein a self-assembled
monolayer of a thiol compound or isocyanide compound having a
terminal reactive group is formed on a surface of the metal
nanoparticle and a photosensitive group is introduced to the
terminal reactive group. The photosensitive metal nanoparticles can
easily form a conductive film or pattern having excellent
conductivity upon exposure to UV, and thus can be applied for
antistatic washable sticky mats or shoes, conductive polyurethane
printer rollers, electromagnetic interference shielding, etc.
Inventors: |
Park; Jong Jin; (Guri-shi,
KR) ; Jeong; Eun Jeong; (Yuseong-gu, KR) ;
Lee; Sang Yoon; (Seocho-gu, KR) |
Correspondence
Address: |
BUCHANAN, INGERSOLL & ROONEY PC
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Suwon-si
KR
|
Family ID: |
33487922 |
Appl. No.: |
11/505324 |
Filed: |
August 17, 2006 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10734138 |
Dec 15, 2003 |
7166412 |
|
|
11505324 |
|
|
|
|
Current U.S.
Class: |
430/281.1 |
Current CPC
Class: |
G03F 7/0047 20130101;
G03F 7/016 20130101; B82Y 30/00 20130101; G03F 7/165 20130101; Y10S
430/117 20130101; G03F 7/027 20130101; B82Y 40/00 20130101 |
Class at
Publication: |
430/281.1 |
International
Class: |
G03C 1/52 20060101
G03C001/52 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 10, 2003 |
KR |
10-2003-0037040 |
Claims
1. A photosensitive metal nanoparticle prepared by (i) forming a
self-assembled monolayer of a thiol or isocyanide compound with a
terminal reactive group, represented by Formula 1, on the surface
of the metal nanoparticle, and then (ii) introducing a
photosensitive group through a reaction with the terminal reactive
group to the monolayer: X-R-(A).sub.a Formula 1 wherein X- is HS--
or NC--; R is a polyvalent organic group of 2-50 carbon atoms; A is
--OH, --COOH, --COCl or --NH.sub.2; and a is an integer of 1-4,
wherein the nanoparticle is polymerizable upon UV exposure.
2. The metal nanoparticle of claim 1, wherein the metal
nanoparticle comprises gold, silver, copper, palladium, or
platinum; R of Formula 1 is polyvalent organic group of 2-50 carbon
atoms, that can include --CONH--, ##STR00005## --COO--, --Si--,
bis-(porphyrin) and/or --CO-- in its carbon chain; the
photosensitive group is an acryl group, an ethylene group, or a
diazo group.
3. The metal nanoparticle of claim 1, wherein the thiol compound is
selected from the group consisting of cystamine(dihydrochloride),
6-mercapto-1-hexanol, 4,4'-thiobiphenol, 2-mercaptoethanol,
1-mercapto-2-propanol, 3-mercapto-1-propanol, 3-mercapto-2-butanol,
3-mercapto-1,2-propanediol, 2,3-dimercapto-1-propanol,
dithiotheretol, dithioerythritol, 1,4-dithio-L-theretol,
3-(methylthio)-1-propanol, 4-(methylthio)-1-butanol,
3-(methylthio)-1-hexanol, 2,2'-thiodiethanol, 2-hydroxyethyl
disulfide, 3,6-dithia-1,8-octanediol, 3,3'-thiodipropanol,
3-methylthio-1,2-propanediol, 3-ethylthio-1,2-propanediol,
D-glucose diethyl mercaptal, 1,4-dithiane-2,5-diol,
1,5-dithiacyclooctan-3-ol, and 4-hydroxythiophenol; and the
isocyanide compound is selected from the group consisting of
4-aminobenzyl cyanide, 4-cyanophenol, and
4'-hydroxy-4-biphenylcarbonitrile.
4-11. (canceled)
12. The metal nanoparticle of claim 2, wherein the thiol compound
is selected from the group consisting of
cystamine(dihydrochloride), 6-mercapto-1-hexanol,
4,4'-thiobiphenol, 2-mercaptoethanol, 1-mercapto-2-propanol,
3-mercapto-1-propanol, 3-mercapto-2-butanol,
3-mercapto-1,2-propanediol, 2,3-dimercapto-1-propanol,
dithiotheretol, dithioerythritol, 1,4-dithio-L-theretol,
3-(methylthio)-1-propanol, 4-(methylthio)-1-butanol,
3-(methylthio)-1-hexanol, 2,2'-thiodiethanol, 2-hydroxyethyl
disulfide, 3,6-dithia-1,8-octanediol, 3,3'-thiodipropanol,
3-methylthio-1,2-propanediol, 3-ethylthio-1,2-propanediol,
D-glucose diethyl mercaptal, 1,4-dithiane-2,5-diol,
1,5-dithiacyclooctan-3-ol, and 4-hydroxythiophenol; and the
isocyanide compound is selected from the group consisting of
4-aminobenzyl cyanide, 4-cyanophenol, and
4'-hydroxy-4-biphenylcarbonitrile.
13-21. (canceled)
22. A photosensitive metal nanoparticle prepared by (i) forming a
self-assembled monolayer of a thiol or isocyanide compound with a
terminal reactive group, represented by Formula 1, on the surface
of the metal nanoparticle, and then (ii) introducing a
photosensitive group through a reaction with the terminal reactive
group to the monolayer: X-R-(A).sub.a Formula 1 wherein X- is HS--
or NC--; R is an at least divalent organic group of 2-50 carbon
atoms; A is --OH, --COOH, --COCl or --NH.sub.2; and a is an integer
of 1-4, wherein the nanoparticle is polymerizable upon UV
exposure.
23. A photosensitive metal nanoparticle prepared by (i) forming a
self-assembled monolayer of a thiol or isocyanide compound with a
terminal reactive group, represented by Formula 1, on the surface
of the metal nanoparticle, and then (ii) introducing a
photosensitive group through a reaction with the terminal reactive
group to the monolayer, wherein the photosensitive group is a
polymerizable group: X-R-(A).sub.a Formula 1 wherein X- is HS-- or
NC--; R is a polyvalent organic group of 2-50 carbon atoms; A is
--OH, --COOH, --COCl or --NH.sub.2; and a is an integer of 1-4,
wherein the nanoparticle is polymerizable upon UV exposure.
24. The metal nanoparticle of claim 23, wherein the metal
nanoparticle comprises gold, silver, copper, palladium, or
platinum; R of Formula 1 is polyvalent organic group of 2-50 carbon
atoms, that can include --CONH--, ##STR00006## --COO--, --Si--,
bis-(porphyrin) and/or --CO-- in its carbon chain; the
photosensitive group is an acryl group, an ethylene group, or a
diazo group.
25. The metal nanoparticle of claim 23, wherein the thiol compound
is selected from the group consisting of
cystamine(dihydrochloride), 6-mercapto-1-hexanol,
4,4'-thiobiphenol, 2-mercaptoethanol, 1-mercapto-2-propanol,
3-mercapto-1-propanol, 3-mercapto-2-butanol,
3-mercapto-1,2-propanediol, 2,3-dimercapto-1-propanol,
dithiotheretol, dithioerythritol, 1,4-dithio-L-theretol,
3-(methylthio)-1-propanol, 4-(methylthio)-1-butanol,
3-(methylthio)-1-hexanol, 2,2'-thiodiethanol, 2-hydroxyethyl
disulfide, 3,6-dithia-1,8-octanediol, 3,3'-thiodipropanol,
3-methylthio-1,2-propanediol, 3-ethylthio-1,2-propanediol,
D-glucose diethyl mercaptal, 1,4-dithiane-2,5-diol,
1,5-dithiacyclooctan-3-ol, and 4-hydroxythiophenol; and the
isocyanide compound is selected from the group consisting of
4-aminobenzyl cyanide, 4-cyanophenol, and
4'-hydroxy-4-biphenylcarbonitrile.
26. The metal nanoparticle of claim 24, wherein the thiol compound
is selected from the group consisting of
cystamine(dihydrochloride), 6-mercapto-1-hexanol,
4,4'-thiobiphenol, 2-mercaptoethanol, 1-mercapto-2-propanol,
3-mercapto-1-propanol, 3-mercapto-2-butanol,
3-mercapto-1,2-propanediol, 2,3-dimercapto-1-propanol,
dithiotheretol, dithioerythritol, 1,4-dithio-L-theretol,
3-(methylthio)-1-propanol, 4-(methylthio)-1-butanol,
3-(methylthio)-1-hexanol, 2,2'-thiodiethanol, 2-hydroxyethyl
disulfide, 3,6-dithia-1,8-octanediol, 3,3'-thiodipropanol,
3-methylthio-1,2-propanediol, 3-ethylthio-1,2-propanediol,
D-glucose diethyl mercaptal, 1,4-dithiane-2,5-diol,
1,5-dithiacyclooctan-3-ol, and 4-hydroxythiophenol; and the
isocyanide compound is selected from the group consisting of
4-aminobenzyl cyanide, 4-cyanophenol, and
4'-hydroxy-4-biphenylcarbonitrile.
27. (canceled)
28. The metal nanoparticle of claim 1, wherein, in step (ii), a
reactive compound comprises the photosensitive group and a
functional group and the functional group reacts with the terminal
reactive group to the monolayer.
29. The metal nanoparticle of claim 22, wherein, in step (ii), a
reactive compound comprises the photosensitive group and a
functional group and the functional group reacts with the terminal
reactive group to the monolayer.
30. The metal nanoparticle of claim 1, wherein the photosensitive
group is covalently bonded to the monolayer.
31. The metal nanoparticle of claim 22, wherein the photosensitive
group is covalently bonded to the monolayer.
32. A photosensitive metal nanoparticle prepared by (i) forming a
self-assembled monolayer of a thiol or isocyanide compound with a
terminal reactive group, represented by Formula 1, on the surface
of the metal nanoparticle, and then (ii) introducing a
photosensitive group through a reaction with the terminal reactive
group to the monolayer, wherein the photosensitive group is a
polymerizable group: X-R-(A).sub.a Formula 1 wherein X- is HS-- or
NC--; R is a polyvalent organic group of 2-50 carbon atoms; A is
--OH, --COOH, --COCl or --NH.sub.2; and a is an integer of 1-4,
wherein the photosensitive group is covalently bonded to the
monolayer.
33. A photosensitive metal nanoparticle prepared by (i) forming a
self-assembled monolayer of a thiol or isocyanide compound with a
terminal reactive group, represented by Formula 1, on the surface
of the metal nanoparticle, and then (ii) introducing a
photosensitive group through a reaction with the terminal reactive
group to the monolayer, wherein the photosensitive group is a
polymerizable group: X-R-(A).sub.a Formula 1 wherein X- is HS-- or
NC--; R is an at least divalent organic group of 2-50 carbon atoms;
A is --OH, --COOH, --COCl or --NH.sub.2; and a is an integer of
1-4, wherein the photosensitive group is covalently bonded to the
monolayer.
34. (canceled)
35. (canceled)
36. (canceled)
37. A photosensitive metal nanoparticle prepared by (i) forming a
self-assembled monolayer of a thiol or isocyanide compound with a
terminal reactive group, represented by Formula 1, on the surface
of the metal nanoparticle, and then (ii) introducing a
photosensitive group through a reaction with the terminal reactive
group to the monolayer, wherein the photosensitive group is a
polymerizable group: X-R-(A).sub.a Formula 1 wherein X- is HS-- or
NC--; R is an at least divalent organic group of 2-50 carbon atoms;
A is --OH, --COOH, --COCl or --NH.sub.2; and a is an integer of
1-4, wherein the nanoparticle is polymerizable upon UV exposure.
Description
[0001] This non-provisional application claims priority under
[0002] 35 U.S.C. .sctn. 119(a) from Korean Patent Application No.
2003-37040 filed on Jun. 10, 2003, which is herein incorporated by
reference.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates, generally, to photosensitive
metal nanoparticles and methods of forming conductive patterns
using the same. More specifically, the present invention relates to
a photosenstivie metal nanoparticle, produced by forming a
self-assembled monolayer of a thiol or isocyanide compound having a
terminal reactive group on its surface and introducing a
photosensitive group through the terminal reactive group; and a
method of forming a conductive pattern using the same.
[0005] 2. Description of the Related Art
[0006] Nano-sized materials, having various electrical, optical and
biological properties depending on the orders and spatial
structures of one-, two- and three-dimensions, have been earnestly
researched for a variety of fields all over the world. Among
various types of the nano-sized materials, metal nano-particle can
be used widely for various applications because, when metal is
reduced to nano-size from its bulk state, metal nano particle has
extremely large surface while there are very few metal atoms in the
particle, and for this reason, metal nano-particle exhibits unique
catalytic, electrical, photoelectric and magnetic properties
[Science, 256, 1425 (1992) and Colloid Polymer. Sci. 273, 101
(1995)]. Metal nanoparticles, showing conductivity through an
electroconductive mechanism of charge (or electron) transfer, have
such a large specific surface area that, even when small amounts of
the nanoparticles are used, their film or pattern can exhibit high
conductivity. In addition, if packing is made more densely by
controlling a particle size within a range of 3-15 nm, a charge
transfer at interfaces of metals can be carried out more easily,
resulting in higher conductivity.
[0007] With great advances in electronic industries, many attempts
have been made to develop highly conductive films or patterns using
various materials. In this regard, it is expected that metal nano
particle can produce a high conductive film or pattern without
performing an etching or sputtering process requiring high vacuum
and/or high temperatures. Once being realized, preparation of a
conductive film by using metal nano particle will be very useful
because the film thus obtained can be transparent under visible
rays by controlling particle size. However, for metal nano
particles to be used in a form of film or pattern, there remains
difficulties to overcome, i.e. controlling and arraying such fine
particles efficiently.
[0008] For efficient arrays of the metal nanoparticles, there are a
few proposed methods of using a self-assembled monolayer. The
self-assembled monolayer is a layer formed on a surface of metal
nanoparticle by arraying molecules of a compound having a
functional group with chemical affinity to a specific metal and,
its thickness can be controlled to the nano-scale, for example,
from 10 to 40 nm. Generally, molecules of a compound having an
amino group (--NH.sub.2), an isocyanide group (--CN), or a thiol
group (--SH) are arrayed on a nano-metal, such as gold, silver,
copper, palladium, or platinum, to form a self-assembled monolayer
[Chem. Rev. 96, 1533 (1996)].
[0009] However, in the case of using the self-assembled monolayer
method, it is not easy to prepare metal nanoparticle films or
patterns in a large size because of difficulty in controlling
molecular orientation or spatial ordering, instability or
aggregation of the metal nanoparticles in a thin film, and defects
of film. For this reason, the metal nano particle or its film or
pattern has been limited in their commercial application.
[0010] Therefore, in the art, there is a strong demand to develop a
novel self-assembled nano structure that enables forming a large
area film or pattern of the metal nanoparticles.
SUMMARY OF THE INVENTION
[0011] The present inventors devoted much effort to satisfying the
demand in the prior art and found that when using photosensitive
metal nano-particles that are prepared by forming a self-assembled
monolayer of thiol (--SH) or isocyanide (--CN) compounds having a
terminal reactive group on a surface of the metal nano-particles
and introducing a photosensitive group through the reaction with
the terminal reactive group to the monolayer, a pattern of the
metal nanoparticles can be easily prepared over a large area via
photolithography process, without performing sputtering or etching
process.
[0012] Based on this founding, a first feature of an embodiment of
the present invention is to provide metal nano particles that can
easily prepare the large area film or pattern. Another preferred
feature of the present invention is to provide a method of forming
a pattern by using the photosensitive nano particles.
[0013] To achieve these and other features of various embodiments
of the present invention, there is provided a photosensitive metal
nanoparticle that is prepared by forming a self-assembled monolayer
of a thiol (--SH) or isocyanide (--CN) compound having a terminal
reactive group on a surface of the metal nano-particle and
introducing a photosensitive group through the reaction with the
terminal reactive group to the monolayer. Also, there is provided a
composition comprising the above photosensitive metal
nanoparticles, a photo-initiator, an organic solvent, and if
necessary, a conductive polymer and/or a non-conductive polymer.
Further, there is provided a method of forming a pattern using the
above photosensitive composition.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] Korean patent application No. 2003-37040, filed on Jun. 10,
2003, and entitled "Photosensitive Metal nanoparticle and Method of
forming Conductive Pattern by using the same," is incorporated by
reference herein in its entirely.
[0015] A photosensitive metal nanoparticle according to the present
invention has a structure as shown schematically in the following,
wherein a thiol or isocyanide compound coupled with a
photosensitive end group forms a self-assembled monolayer on the
metal nanoparticle:
##STR00001##
[0016] Wherein, M is a metal nanoparticle of gold, silver, copper,
palladium, or platinum, whose diameter ranges 1-30 nm;
[0017] X is S or N.ident.C;
[0018] Spacer is a polyvalent organic group of 2-50 carbon atoms,
and preferably, at least divalent organic group of 2-50 carbon
atoms that can include --CONH--,
##STR00002##
--COO--, --Si--, bis-(porphyrin) and/or --CO-- in its carbon
chain;
[0019] n is an integer of 1-500, preferably 1-100, more preferably
1-50;
[0020] a is an integer of 1-4; and
[0021] the photosensitive group is an acryl group, an ethylene
group or a diazo group.
[0022] The photosensitive metal nanoparticles of the present
invention are prepared by (i) forming the self-assembled monolayer
of a thiol or isocyanide compound with a terminal reactive group,
represented by the following Formula 1, on the surface of the metal
nanoparticle, and then (ii) introducing the photosensitive group
through the reaction with the terminal reactive group to the
monolayer:
X-R-(A).sub.a Formula 1
[0023] Wherein X- is HS-- or NC--; R is a polyvalent organic group
of 2-50 carbon atoms, and preferably, at least divalent organic
group of 2-50 carbon atoms, that can include --CONH--, --COO--,
##STR00003##
--Si--, bis-(porphyrin) and/or --CO-- in the carbon chain; A is
--OH, --COOH, --COCl or --NH.sub.2; and a is an integer of 1-4.
[0024] Preferable examples of the thiol compound represented by
Formula 1 include cystamine(dihydrochloride), 6-mercapto-1-hexanol,
2-mercaptoethanol, 4,4'-thiobiphenol, 1-mercapto-2-propanol,
3-mercapto-1-propanol, 3-mercapto-2-butanol,
3-mercapto-1,2-propanediol, 2,3-dimercapto-1-propanol,
dithiotheretol, dithioerythritol, 1,4-dithio-L-theretol,
3-(methylthio)-1-propanol, 4-(methylthio)-1-butanol,
3-(methylthio)-1-hexanol, 2,2'-thiodiethanol, 2-hydroxyethyl
disulfide, 3,6-dithia-1,8-octanediol, 3,3'-thiodipropanol,
3-methylthio-1,2-propanediol, 3-ethylthio-1,2-propanediol,
D-glucose diethyl mercaptal, 1,4-dithiane-2,5-diol,
1,5-dithiacyclooctan-3-ol, or 4-hydroxythiophenol. Further, as a
isocyanide compound (--N.ident.C) that are generally known to be
easily coordinated with a metal through a sigma bond (Langumir, 14,
1684 (1998)), preferable examples in the present invention include
3-(benzylamino)propionitrile, 4-aminobenzyl cyanide, 4-cyanophenol,
or 4'-hydroxy-4-biphenylcarbonitrile.
[0025] In a process of forming a self-assembled monolayer on the
metal nanoparticle according to the present invention, the metal
nanoparticles are dispersed in an organic solvent, along with the
thiol compound or the isocyanide compound represented by Formula 1,
followed by stirring for a predetermined period. In the present
invention, the metal nanoparticles can be obtained by any known
method and for example by the following method: An aqueous solution
containing ions of a metal to be nano-sized (hereinafter, referred
to as "target metal") is reduced with a reducing agent, such as
citrate, EDTA, and NaBH.sub.4, optionally in the presence of a
surfactant including sodium oleate for stabilizing particles,
thereby preparing desired metal nanoparticles. In cases of
preparing copper nano-particles, an aqueous solution of copper
hydrazine carboxylate (Cu(N.sub.2H.sub.3COO).sub.2.2H.sub.2O) is
refluxed at 70-90.degree. C., and preferably, 80.degree. C.,
thereby obtaining copper nanoparticles.
[0026] Also, if desired, nanoparticles inherently containing
self-assembled monolayer can be obtained by the following method:
an organic solution of the thiol or isocyanide compound of Formula
1 is reacted with an aqueous solution of a target metal ion in the
presence of a phase transfer catalyst to obtain a dispersion of
metal compounds surrounded by thiol compound or isocyanide compound
molecules in the organic solution layer. Then the dispersion is
treated with a reducing agent to precipitate the metal
nanoparticles with self-assembled monolayer, which are subsequently
subjected to a centrifugal process.
[0027] Metal nanoparticles, on a surface of which is formed
self-assembled layer of a thiol or isocyanide compound with a
terminal reactive group, are contacted with a reactive compound
having photosensitive moiety to produce photosensitive metal
nanoparticles according to the present invention. The reactive
compound having photosensitive moiety includes not only a
functional group to react with the terminal reactive group (A) at
one end, end but also a photosensitive group, such as acryl group,
ethylene group or diazo group at the other end. Examples of the
reactive compound having photosensitive moiety include, but are not
limited to, acrylochloride, acrylamide, acrylic acid, styrene, or
derivatives of diazonium salts.
[0028] In the present invention, there is further provided a
photosensitive composition including the above photosensitive metal
nanoparticles, a photo-initiator, an organic solvent, and, if
necessary, a conductive polymer and/or non-conductive polymer.
[0029] In the composition of the present invention, the
photosensitive metal nanoparticles as mentioned above are used in
various amounts, depending on the thickness and desired
conductivity of a film or pattern, composition viscosity, or
coating techniques. Preferable content of metal nanoparticles
ranges 1-200 parts by weight based on 100 parts by weight of the
organic solvent, but is not limited thereto.
[0030] The photo-initiator that can be used in the present
invention includes any initiator initiating a radical
polymerization by being decomposed by light, for example,
acetophenone-, benzoin-, benzophenone-, or thioxatone-based
compounds.
[0031] In the present invention, examples of the acetophenone-based
initiator include 4-phenoxy dichloroacetophenone, 4-t-butyl
dichloroacetophenone, 4-t-butyl trichloroacetophenone,
diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one,
1-(4-isopropylphenyl)-2-hydroxy-2-methyl-propane-1-one,
1-(4-dodecylphenyl)-2-hydroxy-2-methylpropane-1-one,
4-(2-hydroxyethoxy)-phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxy
cyclohexyl phenyl ketone,
2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propane-1-one, etc.
The benzoin-based photoinitiator includes benzoin, benzoin methyl
ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin
isobutyl ether, and benzyl dimethyl ketal. The benzophenone-based
photoinitiator includes benzophenone, benzoyl benzoic acid, benzoyl
benzoic acid methyl ester, 4-phenyl benzophenone, hydroxy
benzophenone, 4-benzoyl-4'-methyl diphenyl sulfide,
3,3'-dimethyl-4-methoxy benzophenone, etc. The thioxatone-based
compounds include thioxanthone, 2-chlorothioxanthone,
2-methylthioxanthone, 2,4-dimethylthioxanthone,
isopropylthioxanthone, 2,4-dichlorothioxanthone,
2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, etc.
[0032] In addition to the above initiators,
1-phenyl-1,2-propanedione-2-(O-ethoxycarbonyl)oxime,
2,4,6-trimethyl benzoyl diphenyl phosphine oxide, methyl phenyl
glyoxylate, benzil, 9,10-phenanthraquinone, camphorquinone,
dibenzosuberone, 2-ethylanthraquinone, 4,4'-diethylisophthalo
phenone, or 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone may
be used as the photo-initiator in the present invention. In
particular, when a compound represented by the following Formulas 2
to 5, that is, a photo-initiator including a co-polymerizable
functional group, is used, a level of a residual photo-initiator
that remain un-reacted can be lowered so a more rigid patterns can
be obtained:
##STR00004##
[0033] The amount of the photo-initiator is not particularly
limited and is properly selected, considering an initiating
ability, a film thickness, etc.
[0034] Besides the photo-initiator, there can be included a
co-initiator in the composition of the present invention. Examples
of the co-initiator includes, but are not limited to,
triethanolamine, methyldiethanolamine, triisopropanol amine,
4,4'-dimethylamino benzophenone, 4,4'-diethylamino benzophenone,
2-dimethylamino ethylbenzoate, 4-dimethylamino ethylbenzoate,
2-n-butoxyethyl-4-dimethylaminobenzoate, 4-dimethylamino
isoamylbenzoate, 4-dimethylamino-2-ethylhexyl benzoate, and Eosin
Y. The amount of co-initiator used in the composition is not
limited and, it can be varied depending on initiating ability, the
thickness of the film, etc.
[0035] The organic solvent that can be used for the composition of
the present invention includes, but is not limited to, DMF,
4-hydroxy-4-methyl-2-pentanone, ethylene glycol monoethyl ether and
2-methoxyethanol.
[0036] Also, as a binder, the composition of the present invention
can include a conductive polymer and/or non-conductive polymer to
afford uniformity or various functional abilities to the film when
being polymerized by the exposure to light.
[0037] In the present invention, the conductive polymer is
exemplified by polyacetylene (PA), polythiophene (PT),
poly(3-alkyl)thiophene (P3AT), polypyrrole (PPY),
polyisothianapthelene (PITN), polyethylene dioxythiophene (PEDOT),
polyparaphenylene vinylene (PPV),
poly(2,5-dialkoxy)paraphenylenevinylene, polyparaphenylene (PPP),
polyheptadiyne (PHT), poly(3-hexyl)thiophene (P3HT), polyaniline
(PANI), and mixtures thereof. Number average molecular weight of
the conductive polymer ranges from 1,000 to 30,000, and the polymer
is used in the amount of 1-15 parts by weight, and preferably, 3-10
parts by weight, based on 100 parts by weight of the photosensitive
metal nanoparticles. With the aim of obtaining a rigid film, an
epoxy acrylate derivatives or commercially available epoxy compound
having a glycidyl ether group may be over-coated.
[0038] The non-conductive polymer that can be used in the present
invention includes polyester, polycarbonate, polyvinylalcohol,
polyvinylbutyral, polyacetal, polyarylate, polyamide,
polyamidimide, polyetherimide, polyphenylenether,
polyphenylenesulfide, polyethersulfone, polyetherketone,
polyphthalamide, polyethernitrile, polyethersulfone,
polybenzimidazole, polycarbodiimide, polysiloxane,
polymethylmethacrylate, polymethacrylamide, nitrile rubbers, acryl
rubbers, polyethylenetetrafluoride, epoxy resins, phenol resins,
melamine resins, urea resins, polybutene, polypentene,
ethylene-propylene copolymer, ethylene-butene-diene copolymer,
polybutadiene, polyisoprene, ethylene-propylene-diene copolymer,
butyl rubbers, polymethylpentene, polystyrene, styrene-butadiene
copolymer, hydrogenated styrene-butadiene copolymer, hydrogenated
polyisoprene, hydrogenated polybutadiene, and mixtures thereof. The
non-conductive polymer has a number average molecular weight
ranging from 3,000 to 30,000, in consideration with solubility and
coating ability, and is used in the amount of 0.1-10 parts by
weight based on 100 parts by weight of the photosensitive metal
nanoparticles.
[0039] The composition of the present invention is coated on the
substrate, and exposed to light with or without a photomask having
a desirable pattern, followed by a developing process. Thereby,
without performing an additional sputtering or etching process, the
conductive film or pattern can be simply formed.
[0040] The substrate that can be used in the present invention is
not particularly limited, and can be selected in accordance with
final use. Examples thereof include glass, silicon wafer and
plastic. Coating of the composition can be accomplished by any of
the conventional coating methods well known in the art.
Non-limiting examples of the coating method useful in the present
invention include spin-coating, dip-coating, spray-coating,
flow-coating and screen-printing, while spin-coating is most
preferred in light of convenience and film evenness. For spin
coating, the spin rate is determined depending on viscosity of the
coating composition, desired film thickness and desired
conductivity, preferably between 200 and 3,500 rpm.
[0041] The coated composition is prebaked at 80-120.degree. C.,
preferably, 100.degree. C., for 1-2 min. to evaporate the solvent,
followed by a whole exposure to light or a partial exposure under a
photo-mask having a desirable pattern. Upon the exposure to light,
the radical produced from the photo-initiator initiates the
polymerization of the photosensitive groups introduced to the
surface of the metal nanoparticles, whereby the metal nanoparticles
are cross-linked. At a subsequent developing process, the
cross-linked exposed portion becomes insoluble and has a
drastically decreased solubility, compared with a non-exposed
portion. Due to the difference of the solubility, only the exposed
portion remains on the substrate after developing process, thus
obtaining a desirable pattern. Types of a developer useful in the
present invention are not limited and any organic developer
commonly used in photolithography process can be adopted. DMF,
4-hydroxy-4-methyl-2-pentanone, ethylene glycol monoethyl ether, or
2-methoxyethanol can be preferably used as the developer for a
better stability and uniformity of the film or pattern.
[0042] As for conducting films or patterns formed only with the
conductive polymer, they might show pale green or brown color for a
sufficient conductivity since their conducting properties stemmed
from transfer of .pi. electrons of a double bond in a molecular
chain so a lot of .pi. bonds, possibly causing a coloring problem,
are required for higher conductivity. However, in the present
invention, the film or pattern formed using the photosensitive
metal nanoparticles is transparent under visible rays while it
shows high conductivity.
[0043] According to the present invention, the photosensitive metal
nanoparticles and the composition, if necessary being blended with
the conductive polymer and/or non-conductive polymer, can be used
commercially in the field of antistatic washable sticky mats,
antistatic shoes, conductive polyurethane printer rollers,
conductive wheels and industrial rollers, antistatic pressure
sensitive adhesive films, EMI (ElectroMagnetic Interference
shielding), etc. with success.
[0044] Hereinafter, the present invention will be described in more
detail with the reference to the following Examples. However, these
Examples are provided only for illustrative purposes, and are not
to be construed as limiting the scope of the present invention.
Preparative Example 1
Preparation of Gold Nanoparticles
[0045] 50 mM tetraoctylammonium bromide in 20 ml of toluene was
added with 25 ml of hydrogen perculatorate (HAuCl.sub.4.H.sub.2O)
solution (40 mM), and then stirred. To the reaction solution
(orange color) was added 25 ml of an aqueous solution containing
0.4 g of NaBH.sub.4, and then stirred for 2 hours to obtain a dark
violet reaction mixture. After separation with an organic layer and
an aqueous layer by leaving the reaction mixture, the organic layer
was washed with 0.1 M sulfuric acid solution, 1 M sodium carbonate
solution, and water, dried over MgSO.sub.4, and filtered with a
0.45 .mu.m PTFE syringe filter to obtain gold nano-particles. The
particles thus obtained were dispersed in an organic toluene.
Measurement by TEM (Transmission Electron Microscopy) of the
dispersion shows that gold nanoparticles have an average size of
4-8 nm. From a centrifuge of the dispersion, pure gold
nanoparticles were obtained.
Preparative Example 2
Preparation of Silver Nanoparticles
[0046] A solution prepared from 5 g of AgNO.sub.3 and 0.1 l of
distilled water was added to 0.3 l of an ice solution containing
2.times.10.sup.-3 M sodium borohydride (NaBH.sub.4), and stirred
for 2 hours for reaction. The reaction mixture was centrifuged to
separate a supernatant and slurry thus obtained was dried over
MgSO.sub.4, poured with toluene, and filtered with a 0.45 .mu.m
PTFE syringe filter to obtain nano-particles. The particles thus
obtained were dispersed in an organic toluene. Measurement by TEM
of the dispersion shows that silver nanoparticles have an average
size of 4-8 nm. From a centrifuge of the dispersion, pure silver
nanoparticles were obtained.
Preparative Example 3
Preparation of Copper Nanoparticles
[0047] 300 mg of copper hydrazine carboxylate (CHC) prepared from
cupric chloride and hydrazine carboxylic acid
[0048] (N.sub.2H.sub.3COOH) was dissolved in 100 ml of distilled
water, and refluxed at 80.degree. C. for 3 hours in a nitrogen
atmosphere for reaction. As such, a color change of the solution
from blue to red showed the presence of metallic copper in the
solution. The reaction mixture was centrifuged and pure copper
nanoparticles were separated from the supernatant. The particles
thus obtained were dispersed in an organic toluene. Measurement by
TEM of the dispersion shows that copper nanoparticles have an
average size of 4-8 nm.
Preparative Example 4
Preparation of Palladium Nanoparticles
[0049] Hydrazine (N.sub.2H.sub.4) (40 mM, 10 ml) was added dropwise
to a 100 ml yellowish solution of Na.sub.2PdCl.sub.4 (5 mM, 15 ml),
and then the reaction went for 3 hours, to obtain a brown
dispersion of palladium nanoparticles, which underwent then
centrifuge and pure palladium nanoparticles were separated from the
supernatant. The particles thus obtained were dispersed in an
organic toluene. Measurement by TEM of the dispersion shows that
palladium nanoparticles have an average size of 3-10 nm.
Preparative Example 5
Preparation of Platinum Nanoparticles
[0050] 5 ml of 0.06 M NaBH.sub.4 and 10 ml of 0.0033 M hydrogen
hexachloroplatinate (VI) hexahydrate (H.sub.2PtCl.sub.6.6H.sub.2O)
were mixed with stirring, and reacted for 2 hours, to obtain a dark
brown dispersion. The dispersion thus obtained was allowed to stand
to separate an organic layer from an aqueous layer. The separated
organic layer was dried over MgSO.sub.4 and filtered with a 0.45
.mu.m PTFE syringe filter, resulting in obtaining platinum
nanoparticles having an average size of 2-5 nm (TEM
measurement).
Example 1
Introduction of Photosensitive group to Surface of Gold
Nanoparticles
[0051] 0.2 g of the gold nanoparticles prepared in Preparative
Example 1 was dispersed in 5 g of cystamine dihydrochloride, and
stirred by use of a magnetic bar for 2 hours, filtered, and then
washed with pure water and filtered, to obtain gold nanoparticles
each having a surface substituted with amine groups. While the pH
being maintained at 7.2-7.4 in a buffer solution of 0.05 M
4-(2-hydroxyethyl)-1-piperrazineethanesulfonic acid (HEPES), the
gold nanoparticles were reacted with acrylic acid (0.01 M) for 4
hours, in the presence of
1-ethyl-3(3-dimethylaminopropyl)carbodiimide (EDC) as a
condensation reaction agent. After the completion of the reaction,
resulting metal nanoparticles were filtered, washed twice with THF,
and dried under a reduced pressure, to yield photosensitive metal
nanoparticles having acryl moieties connected through an amide
group on the surface thereof.
Example 2
Introduction of Photosensitive group to Surface of Silver
Nanoparticles
[0052] Silver nanoparticles having acryl moieties connected through
an amide group on the surface thereof were obtained in the same
manner as in Example 1, with the exception that 0.2 g of the silver
nanoparticles prepared in Preparative Example 2 was used, instead
of the gold nanoparticles.
Example 3
Introduction of Photosensitive group to Surface of Copper
Nanoparticles
[0053] Copper nanoparticles having acryl moieties connected through
an amide group on the surface thereof were obtained in the same
manner as in Example 1, with the exception that 0.2 g of the copper
nanoparticles prepared in Preparative Example 3 was used, instead
of the gold nanoparticles.
Example 4
Introduction of Photosensitive group to Surface of Palladium
Nanoparticles
[0054] Palladium nanoparticles having acryl moieties connected
through an amide group on the surface thereof were obtained in the
same manner as in Example 1, with the exception that 0.2 g of the
palladium nanoparticles prepared in Preparative Example 4 was used,
instead of the gold nanoparticles.
Example 5
Introduction of Photosensitive group to Surface of Platinum
Nanoparticles
[0055] Platinum nanoparticles having acryl moieties connected
through an amide group on the surface thereof were obtained in the
same manner as in Example 1, with the exception that 0.2 g of the
platinum nanoparticles prepared in Preparative Example 5 was used,
instead of the gold nanoparticles.
Example 6
Introduction of Photosensitive group to Surface of Gold
Nanoparticles
[0056] 0.2 g of the gold nanoparticles prepared in Preparative
Example 1 was dispersed in 50 ml of 1:1 mixture of conc. sulfuric
acid and 30% hydrogen peroxide, and slowly stirred for 20 min.
Then, the dispersion was diluted with 250 ml of distilled water,
filtered with a 0.2 .mu.m filter, washed five times with 50 ml of
methanol, and dried in an oven at 160.degree. C. for 5 hours. 0.1 g
of the dried gold nanoparticles together with 1.3 g of
4-cyanophenol was added to 200 ml of toluene, and stirred for 72
hours. The resulting product was filtered with a 0.2 .mu.m filter,
washed twice with THF, and dried under a reduced pressure in an
oven at 30.degree. C., to obtain gold nanoparticles each having a
self-assembled monolayer of 4-cyanophenol thereon. 0.1 g of the
gold nanoparticles were added to 200 ml of THF, and ultrasonicated
for 20 min and thus dispersed. To the resultant dispersion was
added 1.5 ml of triethylamine and stirred for 30 min in a nitrogen
atmosphere. Further, 3 ml of acrylochloride was added to the
stirred reaction solution, and reacted for 12 hours while the
reaction temperature was maintained at 0.degree. C. After the
completion of the reaction, the product was washed twice with a
dilute ammonium hydroxide solution and water, and then twice with
THF, followed by filtering by use of a 0.2 .mu.m filter and drying
under a reduced pressure in an oven at 30.degree. C. for 5 hours,
thereby preparing gold nanoparticles on which an acryl group is
substituted.
Example 7
Direct Preparation of Gold Nanoparticles Having Self-Assembled
Monolayer and Introduction of Photosensitive Group to Surface
Thereof
[0057] To a solution of 1.6 g of tetraoctylammonium bromide in 400
ml of toluene was added 0.5 g of hydrogen tetrachlorourate in 150
ml of distilled water, and stirred for 2 hours. To the resulting
solution was added dropwise a solution of 0.2 ml of
6-mercapto-1-hexanol in 50 ml of toluene for 30 min, and stirred
for 4 hours. To the reaction mixture was further added 0.55 g of
NaBH.sub.4, stirred for 4 hours, filtered with a 0.2 .mu.m filter,
and dried under a reduced pressure in an oven at 30.degree. C. for
5 hrs, to prepare gold nanoparticles each having a self-assembled
monolayer of 6-mercapto-1-hexanol thereon. 0.2 g of the gold
nanoparticles were added to 300 ml of THF, and ultrasonicated for
30 min. To the resulting dispersion was added 1.2 ml of
triethylamine and stirred for 30 min in a nitrogen atmosphere.
Further, 3 ml of acrylochloride was added to the stirred reaction
dispersion, and the reaction went for 12 hours while the
temperature was maintained at 0.degree. C. After the completion of
the reaction, the product was washed twice with a dilute ammonium
hydroxide solution and water, and then twice with THF, followed by
filtering by use of a 0.2 .mu.m filter and drying under a reduced
pressure in an oven at 30.degree. C. for 5 hours, thereby obtaining
gold nanoparticles on which an acryl group is substituted.
Example 8
Formation of Negative Pattern Using Photosensitive Metal
Nanoparticles and Measurement of Conductivity
[0058] Coating solutions were prepared respectively, comprising 0.1
g of respective photosensitive metal nanoparticles prepared in
Examples 1 to 7, 0.0005 g of Irgacure 907 purchased from Ciba
Specialty Chemicals Inc. as a photoinitiator, and 1.5 g of
propyleneglycol methyletheracetate (PGMEA) as a solvent. Each
coating solution was ultra-sonicated for 1 hour to mix sufficiently
each component in the coating solution, and then filtered with a
0.5 .mu.m syringe, followed by a spin coating process at 300-500
rpm on a silicon wafer and a drying process at 100.degree. C. for 1
min to remove the solvent remaining on the coated surface. Each
film thus obtained was exposed to ultraviolet rays at 600
mJ/cm.sup.2 under a photo-mask formed with a desired pattern, and
developed in DMF (developer) for 10 sec, to obtain a pattern line
of photosensitive metal nanoparticles in a resolution range of
30-60 .mu.m. Conductivity was measured by calculating a thickness
by use of a 4-point probe. The results are shown in Table 1,
below.
TABLE-US-00001 TABLE 1 Conductivity Pattern Sample (S/cm)
Resolution (.mu.m) Ex. 1 35 40 Ex. 2 30 50 Ex. 3 25 50 Ex. 4 20 60
Ex. 5 25 35 Ex. 6 38 40 Ex. 7 32 50
[0059] From Table 1, it can be seen that the use of the
photosensitive metal nanoparticles of the present invention results
in the formation of the pattern having high resolution and
conductivity even without performing an etching process.
Example 9
Preparation of Conductive Film
[0060] Coating solutions were prepared respectively, comprising 0.1
g of respective photosensitive metal nanoparticles prepared in
Examples 1 to 7, 0.05 g of polythiophene (PT) 3% DMF as a
conductive polymer, 0.0002 g of Irgacure 651 purchased from Ciba
Specialty Chemicals Inc. as a photoinitiator, and 1.5 g of PGMEA as
a solvent. Each coating solution was ultrasonicated for 1 hour to
sufficiently mix components of the coating solution, and then
filtered with a 0.5 .mu.m syringe, followed by a spin coating
process at 500 rpm on a silicon wafer and a drying process at
100.degree. C. for 1 min to remove the solvent remaining on the
coated surface. Each film thus obtained was wholly exposed to light
at 600 mJ/cm.sup.2 without a photo mask, to prepare a conductive
film. Conductivity was measured by calculating a thickness by use
of a Jandal Universal 4 point probe. The results are shown in Table
2, below.
Example 10
Preparation of Conductive Film
[0061] A conductive film was prepared in the same manner as in
Conductive Film Preparation 1, with the exception that 0.001 g of
polystyrene (PS) having a number average molecular weight of 5,000
was used as a polymer binder, instead of polythiophene, and 1.0 g
of PGMEA and 0.3 g of toluene were used as a solvent. Conductivity
was measured, and the results are shown in Table 2, below.
TABLE-US-00002 TABLE 2 Conductivity Conductivity Example 9 (S/cm)
Example 10 (S/cm) Ex. 1 + PT 38 Ex. 1 + PS 30 Ex. 2 + PT 34 Ex. 2 +
PS 25 Ex. 3 + PT 28 Ex. 3 + PS 22 Ex. 4 + PT 25 Ex. 4 + PS 16 Ex. 5
+ PT 28 Ex. 5 + PS 21 Ex. 6 + PT 42 Ex. 6 + PS 32 Ex. 7 + PT 35 Ex.
7 + PS 24
[0062] From Table 2, it can be seen that when the photosensitive
metal nanoparticles of the present invention are mixed with the
conductive polymer, the resulting film has high conductivity.
Further, even when the photosensitive metal nanoparticles are mixed
with a general polymer, the film shows relatively high
conductivity.
[0063] The photosensitive metal nanoparticles of the present
invention can be easily formed into a conductive film or pattern by
exposure to light followed by photopolymerization, and the
resulting film or pattern is excellent in conductivity. Therefore,
photosensitive metal nanoparticles of the present invention can be
used in the fields of antistatic washable sticky mats, antistatic
shoes, conductive polyurethane printer rollers, conductive wheels
and industrial rollers, antistatic pressure sensitive adhesive
films, electromagnetic interference shielding, etc.
[0064] Although the preferred embodiments of the present invention
have been disclosed for illustrative purposes, those skilled in the
art will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
* * * * *