U.S. patent application number 11/915878 was filed with the patent office on 2010-08-26 for methods of preparing high orientation nanoparticle-containing sheets or films using ionic liquids, and the sheets or films produced thereby.
Invention is credited to Dan Daly, Robin D. Rogers.
Application Number | 20100215988 11/915878 |
Document ID | / |
Family ID | 37463738 |
Filed Date | 2010-08-26 |
United States Patent
Application |
20100215988 |
Kind Code |
A1 |
Daly; Dan ; et al. |
August 26, 2010 |
Methods of Preparing High Orientation Nanoparticle-Containing
Sheets or Films Using Ionic Liquids, and the Sheets or Films
Produced Thereby
Abstract
A method is provided for the preparation of nanomaterials, which
involves the dissolution and/or suspension of a combination of (a)
one or more resin substrate materials and (b) one or more magnetic
nanoparticutate substances, in a medium made from one or more ionic
liquids, to provide a mixture, and recovering the solid
nanomaterial by combining the mixture with a non-solvent (solvent
for the ionic liquids but not the other components), while also
applying an electromagnetic field to the mixture during the
recovering step to align the magnetic nanoparticulate substances,
along with the use of the resulting nanomaterials to provide unique
information storage media, particularly in the form of sheets or
films.
Inventors: |
Daly; Dan; (Tuscaloosa,
AL) ; Rogers; Robin D.; (Tuscaloosa, AL) |
Correspondence
Address: |
McKeon Meunier Carlin & Curfman LLC
817 W. Peachtree Street, Suite 900
Atlanta
GA
30308
US
|
Family ID: |
37463738 |
Appl. No.: |
11/915878 |
Filed: |
May 30, 2006 |
PCT Filed: |
May 30, 2006 |
PCT NO: |
PCT/US06/20941 |
371 Date: |
January 23, 2008 |
Current U.S.
Class: |
428/800 ;
427/599 |
Current CPC
Class: |
G11B 5/7013 20130101;
H01F 10/007 20130101; H01F 1/0063 20130101; G11B 5/845
20130101 |
Class at
Publication: |
428/800 ;
427/599 |
International
Class: |
G11B 5/33 20060101
G11B005/33; B01J 19/08 20060101 B01J019/08 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2005 |
US |
11139690 |
Claims
1. A method for making a nanomaterial, comprising: a. dissolving
and/or suspending a combination of (i) one or more resin substrate
materials and (ii) one or more magnetic nanoparticulate substances
in a medium comprising one or more ionic liquids, to provide a
mixture; and b. recovering a solid nanomaterial comprising the one
or more resin substrate materials having the one or more magnetic
nanoparticulate substances distributed therein, by combining the
mixture with a non-solvent; wherein during the recovery step, an
electromagnetic field is applied to the mixture to align the one or
more nanoparticulate substances within the one or more resin
substrate materials.
2. The method of claim 1, wherein the electromagnetic field is a
uniaxial electromagnetic field.
3. The method of claim 1, wherein the electromagnetic field is a
biaxial electromagnetic field.
4. The method of claim 1, wherein the electromagnetic field is a
triaxial electromagnetic field.
5. The method of claim 1, wherein the one or more resin substrate
materials are at least one member selected from the group
consisting of polysaccharides, polyesters, polyamides,
polyurethanes, polysiloxanes, phenol polymers, polysulfides,
polyacetals, polyolefins, acrylates, methacrylates, polyamides,
polyesters, polyimideamides, polybenzoimide, aramides, polyimides,
and dienes.
6. The method of claim 5, wherein the one or more resin substrate
materials comprises cellulose or a derivative thereof.
7. The method of claim 1, wherein the medium comprises one or more
ionic liquids having a cation portion of the one or more ionic
liquids formed from at least one member selected from the group
consisting of imidazoles, pyrazoles, thiazoles, isothiazoles,
azathiozoles, oxothiazoles, oxazines, oxazolines, oxazaboroles,
dithiozoles, triazoles, selenozoles, oxaphospholes, pyrroles,
boroles, furans, thiophens, phospholes, pentazoles, indoles,
indolines, oxazoles, isoxazoles, isotriazoles, tetrazoles,
benzofurans, dibenzofurans, benzothiophens, dibenzothiophens,
thiadiazoles, pyridines, pyrimidines, pyrazines, pyridazines,
piperazines, piperidines, morpholones, pyrans, annolines,
phthalazines, quinazolines and quinoxalines, quinolines,
pyrrolidines, isoquinolines, and combinations thereof.
8. The method of claim 1, wherein the medium comprises one or more
ionic liquids having an anionic portion of the one or more ionic
liquids formed from at least one member selected from the group
consisting of halogens, BX.sub.4.sup.-, PF.sub.6.sup.-,
AsF.sub.6.sup.-, SbF.sub.6.sup.-, NO.sub.2.sup.-, NO.sub.3.sup.-,
SO.sub.4.sup.2-, BR.sub.4.sup.-, carboranes, substituted
carboranes, metallocarboranes, substituted metallocarboranes,
phosphates, phosphites, polyoxometallates, carboxylates,
substituted carboxylates, triflates and noncoordinating anions;
wherein R is at least one member selected from the group consisting
of hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted
cycloalkyl, heteroalkyl, heterocycloalkyl, substituted
heterocycloalkyl, aryl, substituted aryl, heteroaryl, substituted
heteroaryl, alkoxy, aryloxy, acyl, silyl, boryl, phosphino, amino,
thio, seleno, and combinations thereof.
9. The method of claim 1, wherein the medium comprises one or more
ionic liquids selected from the group consisting of [C.sub.2mim]Cl,
[C.sub.3mim]Cl, [C.sub.4mim]Cl, [C.sub.6mim]Cl, [C.sub.smim]Cl,
[C.sub.2mim]I, [C.sub.4mim]I, [C.sub.4mim][PF.sub.6],
[C.sub.2mim][PF.sub.6], [iC.sub.3mim][PF.sub.6],
[C.sub.6mim][PF.sub.6], [C.sub.6mim][PF.sub.6],
[C.sub.4mim][BF.sub.4], [C.sub.2mim][BF.sub.4],
[C.sub.2mim][C.sub.2H.sub.3O.sub.2], and
[C.sub.2mim][C.sub.2F.sub.3O.sub.2].
10. The method of claim 1, wherein the non-solvent is a member
selected from the group consisting of water and alcohols.
11. The method of claim 1, wherein the one or more magnetic
nanoparticulate substances are at least one member selected from
the group consisting of iron, cobalt, nickel, oxides thereof,
alloys thereof and mixtures thereof.
12. An information storage medium, comprising a matrix of one or
more resin substrate materials, having distributed therethrough one
or more magnetic nanoparticulate substances, wherein the one or
more magnetic nanoparticulate substances is aligned within said
matrix and susceptible to change in orientation in response to
application of a recording force.
13. The information storage medium of claim 12, wherein the
information storage medium is in a form of a sheet, a film, or a
disk.
14. A nanomaterial prepared by the method of claim 1.
15. The nanomaterial of claim 14, wherein the nanomaterial is in a
form of a sheet or film.
Description
[0001] This application claims priority to U.S. Utility Application
No. 11/139,690, filed on May 31, 2005. The aforementioned
application is herein incorporated by this reference in its
entirety.
FIELD
[0002] The disclosure generally relates to to the use of ionic
liquids as a medium for preparing sheets and films of a resin
material containing nanoparticles, wherein the nanoparticles are
highly oriented within the sheet or film.
BACKGROUND
[0003] The production of nanomaterials typically requires energy
intensive processes. Particular difficulty has been met when
attempting to capture nanoparticles and prevent their
agglomeration, and then aligning these nanoparticles to produce an
orderly array. This can often be attributed to the importance of
Brownian motion and surface forces in the nanoscale world. These
forces can be significant factors causing agglomeration, such as
when strong surface forces make the moving parts of a NEMS device
stick together and seize up.
[0004] A particularly desired oriented nanomaterial is a sheet or
film made from a resin material, such as cellulose, in which
aligned nanoscale magnetic particles are embedded. Such materials
can be used as "smart paper" and in magnetic information storage
media. While it is well established that the storage capacity of
recording media can be significantly increased by further reducing
the grain size and distribution of magnetic particles in the thin
film in order to increase the signal-to-noise ratio of the medium,
upon reaching the nanoscale for the magnetic particles, it becomes
increasingly difficult to adequately distribute the particles and
avoid agglomeration. Further, it is often necessary to increase the
magnetic anisotropy of the resulting product in order to guarantee
thermal stability of the recorded information.
[0005] Martin et al., Phys. Rev. E, 2000, 61(3), 2818-2830,
discloses the production of magnetic, field-structured composites
(FSCs) by structuring magnetic particle suspensions in uniaxial or
biaxial (e.g., rotating) magnetic fields while polymerizing the
suspending resin. However, since the suspensions are produced by
polymerizing the resin in which the magnetic particles are
suspended, that process can only be used with systems in which the
suspending resin is prepared during the process.
[0006] When a magnetic particle suspension containing multidomain
particles is exposed to a uniaxial magnetic field, the magnetic
dipole moment on the particles will generally increase and align
with the applied field. The particles will then migrate under the
influence of the dipolar interactions with neighboring particles to
form complex chainlike structures. If a magnetic particle
suspension is instead exposed to a biaxial (e.g., rotating)
magnetic field, the induced dipole moments produce a net attractive
interaction in the plane of the field, resulting in formation of a
complex sheetlike structure. Similar effects occur when suspensions
of dielectric particles are subjected to uniaxial or biaxial
electric fields. These materials are known in the art as
field-structured composites (FSCs). FSCs can have large
anisotropies in properties such as conductivity, permittivity,
dielectric breakdown strength, optical transmittance, etc. (Martin
et al., ibid.)
[0007] There is thus a need for a method to reliably produce
nanomaterials having aligned nanoparticles contained in the
material matrix, while also providing high magnetic anisotropy of
the resulting material. The materials and methods disclosed herein
meet these and other needs.
SUMMARY
[0008] In accordance with the purposes of the disclosed materials,
compounds, compositions, articles, and methods, as embodied and
broadly described herein, the disclosed subject matter, in one
aspect, relates to compounds and compositions and methods for
preparing and using such compounds and compositions. In a further
aspect, the disclosed subject matter relates to methods for
producing nanomaterials, particularly in the form of sheets or
films, which have nanoparticles uniformly distributed and embedded
therein. These nanomaterials are also disclosed herein. Further,
nanomaterials having high magnetic anisotropy, permitting their use
in thermally stable information storage media, are disclosed as
well as methods for their preparation. A still further aspect
relates to thermally stable information storage media having high
signal-to-noise ratio and high magnetic anisotropy and methods for
making such media.
[0009] Additional advantages will be set forth in part in the
description that follows, and in part will be obvious from the
description, or can be learned by practice of the aspects described
below. The advantages described below will be realized and attained
by means of the elements and combinations particularly pointed out
in the appended claims. It is to be understood that both the
foregoing general description and the following detailed
description are exemplary and explanatory only and are not
restrictive.
DETAILED DESCRIPTION
[0010] The materials, compounds, compositions, articles, and
methods described herein can be understood more readily by
reference to the following detailed description of specific aspects
of the disclosed subject matter and the Examples included
therein.
[0011] Before the present materials, compounds, compositions,
articles, and methods are disclosed and described, it is to be
understood that the aspects described below are not limited to
specific synthetic methods or specific reagents, as such may, of
course, vary. It is also to be understood that the terminology used
herein is for the purpose of describing particular aspects only and
is not intended to be limiting.
[0012] Also, throughout this specification, various publications
are referenced. The disclosures of these publications in their
entireties are hereby incorporated by reference into this
application in order to more fully describe the state of the art to
which the disclosed matter pertains. The references disclosed are
also individually and specifically incorporated by reference herein
for the material contained in them that is discussed in the
sentence in which the reference is relied upon.
[0013] In this specification and in the claims that follow,
reference will be made to a number of terms, which shall be defined
to have the following meanings:
[0014] Throughout the description and claims of this specification
the word "comprise" and other forms of the word, such as
"comprising" and "comprises," means including but not limited to,
and is not intended to exclude, for example, other additives,
components, integers, or steps.
[0015] As used in the description and the appended claims, the
singular forms "a," "an," and "the" include plural referents unless
the context clearly dictates otherwise. Thus, for example,
reference to "a compound" includes mixtures of two or more such
compounds, reference to "an ionic liquid" includes mixtures of two
or more such ionic liquids, reference to "the film" includes
mixtures of two or more such films, and the like.
[0016] "Optional" or "optionally" means that the subsequently
described event or circumstance can or cannot occur, and that the
description includes instances where the event or circumstance
occurs and instances where it does not.
[0017] Ranges can be expressed herein as from "about" one
particular value, and/or to "about" another particular value. When
such a range is expressed, another aspect includes from the one
particular value and/or to the other particular value. Similarly,
when values are expressed as approximations, by use of the
antecedent "about," it will be understood that the particular value
forms another aspect. It will be further understood that the
endpoints of each of the ranges are significant both in relation to
the other endpoint, and independently of the other endpoint. It is
also understood that there are a number of values disclosed herein,
and that each value is also herein disclosed as "about" that
particular value in addition to the value itself. For example, if
the value "10" is disclosed, then "about 10" is also disclosed. It
is also understood that when a value is disclosed that "less than
or equal to" the value, "greater than or equal to the value" and
possible ranges between values are also disclosed, as appropriately
understood by the skilled artisan. For example, if the value "10"
is disclosed, then "less than or equal to 10" as well as "greater
than or equal to 10" is also disclosed. It is also understood that
throughout the application data are provided in a number of
different formats and that these data represent endpoints and
starting points and ranges for any combination of the data points.
For example, if a particular data point "10" and a particular data
point "15" are disclosed, it is understood that greater than,
greater than or equal to, less than, less than or equal to, and
equal to 10 and 15 are considered disclosed as well as between 10
and 15. It is also understood that each unit between two particular
units are also disclosed. For example, if 10 and 15 are disclosed,
then 11, 12, 13, and 14 are also disclosed.
[0018] The term "nanomaterials" as used herein refers to
compositions which contain one or more nanoparticulate substances
along with a resin substrate material.
[0019] The term "resin substrate material(s)" as used herein
includes one or more polymers, one or more copolymers, and
combinations thereof.
[0020] The term "blend" as used herein, includes two or more
polymers, two or more copolymers, and combinations thereof,
immiscible or miscible at the molecular level or domain level.
[0021] The term "polymeric materials" includes one or more
polymers, one or more copolymers, and combinations thereof.
[0022] The term "non-solvent" as used herein refers to a substance
miscible with the one or more ionic liquids, but immiscible with
the one or more resin substrate materials and the one or more
nanoparticulate substances.
[0023] The term "substituted" as used herein is contemplated to
include all permissible substituents of organic compounds. In a
broad aspect, the permissible substituents include acyclic and
cyclic, branched and unbranched, carbocyclic and heterocyclic, and
aromatic and nonaromatic substituents of organic compounds.
Illustrative substituents include, for example, those described
below. The permissible substituents can be one or more and the same
or different for appropriate organic compounds. For purposes of
this disclosure, the heteroatoms, such as nitrogen, can have
hydrogen substituents and/or any permissible substituents of
organic compounds described herein which satisfy the valences of
the heteroatoms. This disclosure is not intended to be limited in
any manner by the permissible substituents of organic compounds.
Also, the terms "substitution" or "substituted with" include the
implicit proviso that such substitution is in accordance with
permitted valence of the substituted atom and the substituent, and
that the substitution results in a stable compound, e.g., a
compound that does not spontaneously undergo transformation such as
by rearrangement, cyclization, elimination, etc.
[0024] A "residue" of a chemical species, as used in the
specification and concluding claims, refers to the moiety that is
the resulting product of the chemical species in a particular
reaction scheme or subsequent formulation or chemical product,
regardless of whether the moiety is actually obtained from the
chemical species.
[0025] "A.sup.1," "A.sup.2," "A.sup.3," and "A.sup.4" are used
herein as generic symbols to represent various specific
substituents. These symbols can be any substituent, not limited to
those disclosed herein, and when they are defined to be certain
substituents in one instance, they can, in another instance, be
defined as some other substituents.
[0026] The term "alkyl" as used herein is a branched or unbranched
saturated hydrocarbon group of 1 to 24 carbon atoms, such as
methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl,
t-butyl, n-pentyl, isopentyl, s-pentyl, neopentyl, hexyl, heptyl,
octyl, nonyl, decyl, dode cyl, tetradecyl, hexadecyl, eicosyl,
tetracosyl, and the like. The alkyl group can also be substituted
or unsubstituted. The alkyl group can be substituted with one or
more groups including, but not limited to, substituted or
unsubstituted alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl,
alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino,
carboxylic acid, ester, ether, halide, hydroxy, ketone, azide,
nitro, silyl, sulfo-oxo, or thiol, as described herein. A "lower
alkyl" group is an alkyl group containing from one to six carbon
atoms.
[0027] The term "cycloalkyl" as used herein is a non-aromatic
carbon-based ring composed of at least three carbon atoms. Examples
of cycloalkyl groups include, but are not limited to, cyclopropyl,
cyclobutyl, cyclopentyl, cyclohexyl, norbomyl, and the like. The
term "heterocycloalkyl" is a type of cycloalkyl group as defined
above, and is included within the meaning of the term "cycloalkyl,"
where at least one of the carbon atoms of the ring is replaced with
a heteroatom such as, but not limited to, nitrogen, oxygen, sulfur,
or phosphorus. The cycloalkyl group and heterocycloalkyl group can
be substituted or unsubstituted. The cycloalkyl group and
heterocycloalkyl group can be substituted with one or more groups
including, but not limited to, substituted or unsubstituted alkyl,
cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl,
aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether,
halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiol
as described herein.
[0028] The term "alkoxy" as used herein is an alkyl or cycloalkyl
group bonded through an ether linkage; that is, an "alkoxy" group
can be defined as --OA.sup.1 where A.sup.1 is alkyl or cycloalkyl
as defined above. "Alkoxy" also includes polymers of alkoxy groups
as just described; that is, an alkoxy can be a polyether such as
--OA.sup.1--OA.sup.2 or --OA.sup.1--(OA.sup.2).sub.a--OA.sup.3,
where "a" is an integer of from 1 to 200 and A.sup.1, A.sup.2, and
A.sup.3 are alkyl and/or cycloalkyl groups.
[0029] The term "alkenyl" as used herein is a hydrocarbon group of
from 2 to 24 carbon atoms with a structural formula containing at
least one carbon-carbon double bond. Asymmetric structures such as
(A.sup.1A.sup.2)C.ident.C(A.sup.3A.sup.4) are intended to include
both the E and Z isomers. This may be presumed in structural
formulae herein wherein an asymmetric alkene is present, or it may
be explicitly indicated by the bond symbol C.ident.C. The alkenyl
group can be substituted with one or more groups including, but not
limited to, substituted or unsubstituted alkyl, cycloalkyl, alkoxy,
alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl,
aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy,
ketone, azide, nitro, silyl, sulfo-oxo, or thiol, as described
herein.
[0030] The term "cycloalkenyl" as used herein is a non-aromatic
carbon-based ring composed of at least three carbon atoms and
containing at least one carbon-carbon double bound, i.e.,
C.ident.C. Examples of cycloalkenyl groups include, but are not
limited to, cyclopropenyl, cyclobutenyl, cyclopentenyl,
cyclopentadienyl, cyclohexenyl, cyclohexadienyl, norbomenyl, and
the like. The term "heterocycloalkenyl" is a type of cycloalkenyl
group as defined above, and is included within the meaning of the
term "cycloalkenyl," where at least one of the carbon atoms of the
ring is replaced with a heteroatom such as, but not limited to,
nitrogen, oxygen, sulfur, or phosphorus. The cycloalkenyl group and
heterocycloalkenyl group can be substituted or unsubstituted. The
cycloalkenyl group and heterocycloalkenyl group can be substituted
with one or more groups including, but not limited to, substituted
or unsubstituted alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl,
alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino,
carboxylic acid, ester, ether, halide, hydroxy, ketone, azide,
nitro, silyl, sulfo-oxo, or thiol as described herein.
[0031] The term "alkynyl" as used herein is a hydrocarbon group of
2 to 24 carbon atoms with a structural formula containing at least
one carbon-carbon triple bond. The alkynyl group can be
unsubstituted or substituted with one or more groups including, but
not limited to, substituted or unsubstituted alkyl, cycloalkyl,
alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl,
heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide,
hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiol, as
described herein.
[0032] The term "cycloalkynyl" as used herein is a non-aromatic
carbon-based ring composed of at least seven carbon atoms and
containing at least one carbon-carbon tripple bound. Examples of
cycloalkynyl groups include, but are not limited to, cycloheptynyl,
cyclooctynyl, cyclononynyl, and the like. The term
"heterocycloalkynyl" is a type of cycloalkenyl group as defined
above, and is included within the meaning of the term
"cycloalkynyl," where at least one of the carbon atoms of the ring
is replaced with a heteroatom such as, but not limited to,
nitrogen, oxygen, sulfur, or phosphorus. The cycloalkynyl group and
heterocycloalkynyl group can be substituted or unsubstituted. The
cycloalkynyl group and heterocycloalkynyl group can be substituted
with one or more groups including, but not limited to, substituted
or unsubstituted alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl,
alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino,
carboxylic acid, ester, ether, halide, hydroxy, ketone, azide,
nitro, silyl, sulfo-oxo, or thiol as described herein.
[0033] The term "aryl" as used herein is a group that contains any
carbon-based aromatic group including, but not limited to, benzene,
naphthalene, phenyl, biphenyl, phenoxybenzene, and the like. The
term "aryl" also includes "heteroaryl," which is defined as a group
that contains an aromatic group that has at least one heteroatom
incorporated within the ring of the aromatic group. Examples of
heteroatoms include, but are not limited to, nitrogen, oxygen,
sulfur, and phosphorus. Likewise, the term "non-heteroaryl," which
is also included in the term "aryl," defines a group that contains
an aromatic group that does not contain a heteroatom. The aryl
group can be substituted or unsubstituted. The aryl group can be
substituted with one or more groups including, but not limited to,
substituted or unsubstituted alkyl, cycloalkyl, alkoxy, alkenyl,
cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde,
amino, carboxylic acid, boronic acid, ester, ether, halide,
hydroxy, ketone, azide, nitro, hydroxamate, silyl, sulfo-oxo, or
thiol as described herein. The term "biaryl" is a specific type of
aryl group and is included in the definition of "aryl." Biaryl
refers to two aryl groups that are bound together via a fused ring
structure, as in naphthalene, or are attached via one or more
carbon-carbon bonds, as in biphenyl.
[0034] The terms "amine" or "amino" as used herein are represented
by the formula NA.sup.1A.sup.2A.sup.3, where A.sup.1, A2, and A3
can be, independently, hydrogen or substituted or unsubstituted
alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl,
aryl, or heteroaryl group as described herein.
[0035] The term "boryl" as used herein is represented by the
formula --B(A.sup.1).sub.2, where A.sup.1 can be hydroxyl, a
substituted or unsubstituted alkyl, cycloalkyl, alkenyl,
cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as
described herein. Also included within the meaning of this term are
ionized compounds, salts, and tetravalent structures.
[0036] The term "carboxylic acid" as used herein is represented by
the formula --C(O)OH. Throughout this specification "C(O)" is a
short hand notation for a carbonyl group, i.e., C.ident.O.
[0037] The term "ester" as used herein is represented by the
formula --OC(O)A.sup.1 or --C(O)OA.sup.1, where A.sup.1 can be a
substituted or unsubstituted alkyl, cycloalkyl, alkenyl,
cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as
described herein. The term "polyester" as used herein is
represented by the formula --(A.sup.1O(O)C--A.sup.2--C(O)O).sub.a--
or --(A.sup.1O(O)C--A.sup.2--OC(O)).sub.a--, where A.sup.1 and
A.sup.2 can be, independently, a substituted or unsubstituted
alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl,
aryl, or heteroaryl group described herein and "a" is an interger
from 1 to 500. "Polyester" is as the term used to describe a group
that is produced by the reaction between a compound having at least
two carboxylic acid groups with a compound having at least two
hydroxyl groups.
[0038] The term "ether" as used herein is represented by the
formula A.sup.1OA.sup.2, where A.sup.1 and A.sup.2 can be,
independently, a substituted or unsubstituted alkyl, cycloalkyl,
alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl
group described herein. The term "polyether" as used herein is
represented by the formula --(A.sup.1O--A.sup.2O).sub.a--, where
A.sup.1 and A.sup.2 can be, independently, a substituted or
unsubstituted alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl,
cycloalkynyl, aryl, or heteroaryl group described herein and "a" is
an integer of from 1 to 500. Examples of polyether groups include
polyethylene oxide, polypropylene oxide, and polybutylene
oxide.
[0039] The term "halide" as used herein refers to the halogens
fluorine, chlorine, bromine, and iodine.
[0040] The term "hydroxyl" as used herein is represented by the
formula --OH.
[0041] The term "ketone" as used herein is represented by the
formula A.sup.1C(O)A.sup.2, where A.sup.l and A.sup.2 can be,
independently, a substituted or unsubstituted alkyl, cycloalkyl,
alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl
group as described herein.
[0042] The term "azide" as used herein is represented by the
formula --N.sub.3.
[0043] The term "nitro" as used herein is represented by the
formula --NO.sub.2.
[0044] The term "nitrile" as used herein is represented by the
formula --CN.
[0045] The term "silyl" as used herein is represented by the
formula --SiA.sup.1A.sup.2A.sup.3, where A.sup.1, A.sup.2, and
A.sup.3 can be, independently, hydrogen or a substituted or
unsubstituted alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl,
alkynyl, cycloalkynyl, aryl, or heteroaryl group as described
herein.
[0046] The term "sulfo-oxo" as used herein is represented by the
formulas --S(O)A.sup.1, --S(O).sub.2A.sup.1, --OS(O).sub.2A.sup.1,
or --OS(O).sub.2OA.sup.1, where A.sup.1 can be hydrogen or a
substituted or unsubstituted alkyl, cycloalkyl, alkenyl,
cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as
described herein. Throughout this specification "S(O)" is a short
hand notation for S.ident.O. The term "sulfonyl" is used herein to
refer to the sulfo-oxo group represented by the formula
--S(O).sub.2A.sup.1, where A.sup.1 can be hydrogen or a substituted
or unsubstituted alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl,
cycloalkynyl, aryl, or heteroaryl group as described herein. The
term "sulfone" as used herein is represented by the formula
A.sup.1S(O).sub.2A.sup.2, where A.sup.1 and A.sup.2 can be,
independently, a substituted or unsubstituted alkyl, cycloalkyl,
alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl
group as described herein. The term "sulfoxide" as used herein is
represented by the formula A.sup.1S(O)A.sup.2, where A.sup.1 and
A.sup.2 can be, independently, a substituted or unsubstituted
alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl,
aryl, or heteroaryl group as described herein.
[0047] The term "thiol" as used herein is represented by the
formula --SH.
[0048] Reference will now be made in detail to specific aspects of
the disclosed materials, compounds, compositions, articles, and
methods, examples of which are illustrated in the accompanying
Examples.
[0049] Certain materials, compounds, compositions, and components
disclosed herein can be obtained commercially or readily
synthesized using techniques generally known to those of skill in
the art. For example, the starting materials and reagents used in
preparing the disclosed compounds and compositions are either
available from commercial suppliers such as Aldrich Chemical Co.,
(Milwaukee, Wis.), Acros Organics (Morris Plains, N.J.), Fisher
Scientific (Pittsburgh, Pa.), or Sigma (St. Louis, Mo.) or are
prepared by methods known to those skilled in the art following
procedures set forth in references such as Fieser and Fieser's
Reagents for Organic Synthesis, Volumes 1-17 (John Wiley and Sons,
1991); Rodd's Chemistry of Carbon Compounds, Volumes 1-5 and
Supplementals (Elsevier Science Publishers, 1989); Organic
Reactions, Volumes 1-40 (John Wiley and Sons, 1991); March's
Advanced Organic Chemistry, (John Wiley and Sons, 4th Edition); and
Larock's Comprehensive Organic Transformations (VCH Publishers
Inc., 1989).
[0050] Also, disclosed herein are materials, compounds,
compositions, and components that can be used for, can be used in
conjunction with, can be used in preparation for, or are products
of the disclosed methods and compositions. These and other
materials are disclosed herein, and it is understood that when
combinations, subsets, interactions, groups, etc. of these
materials are disclosed that while specific reference of each
various individual and collective combinations and permutation of
these compounds may not be explicitly disclosed, each is
specifically contemplated and described herein. For example, if a
compound is disclosed and a number of modifications that can be
made to a number of components of the compound are discussed, each
and every combination and permutation that are possible are
specifically contemplated unless specifically indicated to the
contrary. Thus, if a class of components A, B, and C are disclosed
as well as a class of components D, E, and F and an example of a
combination compound A-D is disclosed, then even if each is not
individually recited, each is individually and collectively
contemplated. Thus, in this example, each of the combinations A-E,
A-F, B-D, B-E, B-F, C-D, C-E, and C-F are specifically contemplated
and should be considered disclosed from disclosure of A, B, and C;
D, E, and F; and the example combination A-D. Likewise, any subset
or combination of these is also specifically contemplated and
disclosed. Thus, for example, the sub-group of A-E, B-F, and C-E
are specifically contemplated and should be considered disclosed
from disclosure of A, B, and C; D, E, and F; and the example
combination A-D. This concept applies to all aspects of this
disclosure including, but not limited to, steps in methods of
making and using the disclosed compositions. Thus, if there are a
variety of additional steps that can be performed it is understood
that each of these additional steps can be performed with any
specific aspect or combination of aspects of the disclosed methods,
and that each such combination is specifically contemplated and
should be considered disclosed.
[0051] Disclosed herein is process comprising dissolving and/or
suspending one or more resin substrate materials and one or more
magnetic nanoparticulate substances in a medium comprising one or
more ionic liquids to provide a mixture, and recovering a solid
nanomaterial comprising the one or more resin substrate materials
having the one or more magnetic nanoparticulate substances
distributed therein by combining the mixture with a substance
miscible with said one or more ionic liquids, but immiscible with
said one or more resin substrate materials and said one or more
nanoparticulate substances, wherein during said recovery step, an
electromagnetic field is applied to the mixture to align said one
or more nanoparticulate substances within said one or more resin
substrate materials; and the nanomaterials produced thereby, along
with their use in providing information storage media such as smart
paper and magnetic recording tape.
[0052] Ionic liquids are a well-established class of liquids
containing solely ionized species, and having melting points
largely below 150.degree. C., or most preferably below 100.degree.
C. In most cases, ionic liquids (ILs) are organic salts containing
one or more cations that are typically ammonium, imidazolium, or
pyridinium ions, although many other types are known.
[0053] Disclosed herein are processes for the production of
nanomaterials in which the nanoparticles are aligned and
substantially uniformly distributed within the resin substrate
material. The process comprises dissolving and/or suspending one or
more resin substrate materials and one or more magnetic
nanoparticulate substances in a medium comprising one or more ionic
liquids to provide a mixture, and recovering a solid nanomaterial
comprising the one or more resin substrate materials having the one
or more magnetic nanoparticulate substances distributed therein by
combining the mixture with a non-solvent, wherein during the
recovery step, an electromagnetic field is applied to the mixture
to align the one or more nanoparticulate substances within the one
or more resin substrate materials.
[0054] The unique solvation properties of ionic liquids allow for
the dissolution of a wide range of resin substrate materials,
particularly materials useful in the production of magnetic
information storage media, such as polyesters and cellulose
materials. Further, these unique solvation properties also allow
the ionic liquid to dissolve a wide range of magnetic
nanoparticulate substances. This dual dissolution ability permits
intimate mixing of the resin substrate materials and the magnetic
nanoparticulate substances, which, upon adding the mixture to a
"non-solvent" in turn, allows for the creation of nanomaterials,
most preferably in the form of sheets or films, wherein the
magnetic nanoparticulate substances are distributed throughout the
resin substrate material and are aligned due to the presence of the
electromagnetic field during the reconstitution step during which
the nanoparticles are still mobile and alignable. The resulting
nanomaterials can be in any desired form, e.g., in the form of
sheets or films, suitable for the creation of information storage
media, due to the high anisotropy and alignment of the
nanoparticles within the resin substrate material. These
information storage media can be recorded using any conventional
recording force used for the particular type of recording medium,
such as electrical, magnetic, light, heat, etc. Suitable
information storage media include, but are not limited to,
materials known as "smart paper" (also known in the art as e-ink,
reusable sign media or e-paper; such as the electronic-display
technology based on full-color programmable media produced by
Magink, from Neveh-Ilan, Israel) and in magnetic storage tapes or
disks.
[0055] Suitable non-solvents include, but are not limited to, polar
liquid systems, such as water, alcohols, and other hydric liquids.
In one example, the ionic liquid is removed by the addition of
water.
[0056] The magnetic field used can be uniaxial, biaxial, or
triaxial, depending on the type of orientation of the nanoparticles
desired, and is applied to the resin substrate material containing
nanoparticles in accordance with methods well known in the art. The
magnetic field used to align the nanoparticulate materials can have
any desired field strength, for example, in a range of from about
10 to about 1000 Gauss, or from about 50 to about 350 Gauss.
[0057] The processes disclosed herein can use polymers that contain
various repeating monomeric units as the resin substrate material.
These monomer units can contain polar, non-ionic, and charged
groups, including, but not limited to, --NH.sub.2--, --NHR,
--NR.sub.2, --N.sup.+R.sub.3X.sup.-, --O--, --OH, --COOH,
--COO.sup.-M.sup.+, --SH, --SO.sub.3M.sup.+,
--PO.sub.3.sup.2-M.sup.2+, --PR.sub.3, --NH--CO--NH.sub.2 and
--NHC(NH)NH.sub.2. These groups may be present in sufficient
numbers along, or pendent to, the polymeric backbone, in polymers,
such as, polyacrylamide, polyvinyl alcohol, polyvinyl acetate,
polyamides, polyesters, polyimideamides, polybenzoimide, aramides,
polyimides, poly(N-vinylpyrrolidinone), and poly(hydroxyethyl
acrylate). These groups also impact the solubility of the
respective polymer. The polymer can have a complex structure due to
intramolecular hydrogen bonding, ionic interactions, intermolecular
interactions, and chain-chain complexation. These interactions
govern the solution properties and performance.
[0058] Solvent properties such as polarity, charge, hydrogen
bonding, interactions between the polymer and the solvent can also
be considered for effective dissolution and blending.
[0059] Three abundant polysaccharides, cellulose, starch, and
chitin, do not dissolve in most common solvents directly due to
their unique molecular and supermolecular structure. One way to
enhance a polymer's dissolution is to chemically modify it, for
example, by adding one or more hydroxyethyl, hydroxypropyl, methyl,
carboxymethyl, sulfate, or phosphate groups to the polymer
structure. These modifications alter the polymer's aforementioned
interactions and can thereby increase its solubility in common
organic solvents and in many cases water. Instead of chemically
altering the polymer, the disclosed methods provides a method of
processing the virgin polymer using ionic liquids as the solvent,
thus lessening chemical usage and processing steps and making the
overall process more environmentally and economically sustainable.
It is contemplated, however, that polymers modified as described
can also be used in the disclosed methods. The use of cellulose, in
particular, is useful in the production of smart papers, which can
store information and can be reused upon re-recording of the
information on the paper.
[0060] Ionic Liquids ("ILs") have a more complex solvent behavior
compared with traditional aqueous and organic solvent, because ILs
are salts and not a molecular, nonionic solvent. Types of
interactions between ILs with many solutes include dispersion,
.pi.-.pi., .sigma.-.pi., hydrogen bonding, dipolar and
ionic/charge-charge. The Abraham solvation equation is a useful
method used to characterize ILs solvent property to understand the
polymer dissolution behavior in ILs. Some typical C.sub.4mim ILs
interaction parameters are shown in Table 1 below. ILs that have
strong dipolarity, hydrogen bond accepting (A) ability, and
hydrogen bond donating (B) ability are compared with other solvents
that are capable of dissolving cellulose (see table below)
C.sub.4mim Cl, one of the most unique solvents, shows the largest A
(a=4.860) and a strong ability to interact with solute molecules
via non-bonding or .pi.-electron interaction (r=0.408). The cation
C.sub.4mim, in combination with the anion Cl.sup.-, exhibits
significant ability to interact with .pi.-systems of solute
molecules (Anderson, J. L. et al). The smaller Gibbs free energies
of hydration of Cl (.DELTA.G.sub.hyd=-347 kJ/mol) shows a larger
HBA 4.860, compared to that of 1.660 of [BF.sub.4.sup.-]
(.DELTA.G.sub.hyd=-200 kJ/mol).
TABLE-US-00001 TABLE 1 hydrogen hydrogen excess Polarity/ bond bond
Ionic molecular polarisability acidity basicity molecular liquid
refraction parameter parameter parameter volume C.sub.4mim C1 0.408
1.826 4.860 -0.121 0.392 C.sub.4mim -0.141 1.365 1.660 -0.283 0.473
BF.sub.4 C.sub.4mim 0 1.540 1.369 0 0.439 PF.sub.6 Dimethyl- 0.36
1.33 0 0.78 0.787 acetamide Dimethyl- 0.37 1.31 0 0.74 0.6468
formamide Dimethyl- 0.52 1.74 0 0.88 0.776 sulfoxide
[0061] In some examples, the disclosed processes provide the mixing
of one or more resin substrate materials (polymers and/or
copolymers) and one or more magnetic nanoparticulate substances
with one or more ionic liquids. Mixing can be accomplished by any
conventional procedure in the art, including, but not limited to,
various stirring mechanisms, agitation mechanisms, sonication, and
vortexing. In one specific example, the mixture is heated to about
100.degree. C. The addition of heat can be supplied by any
conventional and non-conventional heat source, including, but not
limited to, a microwave source. It has been found that microwave
radiation not only provides heat but also facilitates the
dissolution of polymeric materials in the ionic liquid. While not
wishing to be bound by theory, it is believed that the facilitated
dissolution can be due to the absorption and resulting increase
molecular motions of solute and solvent.
[0062] In other examples wherein the resin substrate material is
cellulose, ionic liquids can allow for the dissolution of cellulose
without derivatization in high concentration. Such a solution can
be heated to about 100.degree. C., or to about 80.degree. C., in an
ultrasonic bath. This heating can be effectively accomplished by
using microwave radiation supplied by a domestic microwave oven. In
one example, an admixture of hydrophilic ionic liquid and cellulose
is heated to a temperature of from about 100.degree. C. to about
150.degree. C. using microwave radiation. Further methods for
dissolution of cellulose in ionic liquids are described in U.S.
Pat. Nos. 6,824,599 and 6,808,557, which are incorporated by
reference herein in their entireties for their teachings of ionic
liquids and methods for using them.
Resin Substrate Materials
[0063] Suitable resin substrate materials for use in the process of
the present invention include, but are not limited to, polymers and
copolymers formed by step, chain, ionic, ring-opening, and
catalyzed polymerizations.
[0064] Suitable polymers and copolymers can be derived from natural
and synthetic sources including, but not limited to,
polysaccharides, polyester, polyamide, polyurethane, polysiloxane,
phenol polymers, polysulfide, polyacetal, polyolefins, acrylates,
methacrylates and dienes. In particular, preferred polymers
include, but are not limited to, cellulose, hemicellulose, starch,
chitin, silk, wool, poly-2-hydroxymethylmethacrylate,
poly-2-hydroxyethylmethacrylate, polyamides, polyesters,
polyimideamides, polybenzoimide, aramides, polyimides, polyvinyl
alcohol, polyaniline, polyethylene glycol, polyacrylonitrile,
polystyrene, polyethylene oxide with terminal amine groups, linear
polyethyleneimine, and branched polyethyleneimine.
[0065] Monomers include, but are not limited to, .alpha.-olefins,
2-hydroxyalkylmethacrylate, aniline, acrylonitrile, ethylene,
isobutylene, styrene, vinyl chloride, vinyl acetate, vinyl alcohol,
methyl methacrylate, ethylene glycol, cellobiose, vinylidene
chloride, tetrafluoroethylene, formaldehyde, acetaldehyde,
vinylpyrrolidinone, butadiene, and isoprene.
Magnetic Nanoparticulate Substances
[0066] The magnetic nanoparticulate substances suitable for the
disclosed methods and compostions can be any magnetic material
having nanoscale dimensions that is susceptible of alignment or
orientation in the presence of an electromagnetic field. Suitable
magnetic nanoparticulate substances include, but are not limited
to, iron, cobalt, nickel, oxides thereof and mixtures/alloys
thereof. Further examples of magnetic nanoparticulate substances
include one or more of cobalt particles, iron-cobalt particles,
iron oxide particles, nickel particles, and mixtures thereof.
Ionic Liquids
[0067] The ionic liquids comprise one or more cations and one or
more anions. In many examples, a mixture of cations and anions is
selected and optimized for the dissolution of a particular
combination of one or more resin substrate materials and one or
more magnetic nanoparticulate materials.
[0068] In other examples, the cation is derived from an organic
compound including, but not limited to, the following
heterocyclics: imidazoles, pyrazoles, thiazoles, isothiazoles,
azathiozoles, oxothiazoles, oxazines, oxazolines, oxazaboroles,
dithiozoles, triazoles, selenozoles, oxaphospholes, pyrroles,
boroles, furans, thiophens, phospholes, pentazoles, indoles,
indolines, oxazoles, isoxazoles, isotriazoles, tetrazoles,
benzofurans, dibenzofurans, benzothiophens, dibenzothiophens,
thiadiazoles, pyridines, pyrimidines, pyrazines, pyridazines,
piperazines, piperidines, morpholones, pyrans, annolines,
phthalazines, quinazolines and quinoxalines, quinolines,
pyrrolidines, isoquinolines, and combinations thereof.
[0069] The anionic portion of the ionic liquid can comprise at
least one of the following groups: halogens, BX.sub.4.sup.-,
PF.sub.6.sup.-, AsF.sub.6.sup.-, SbF.sub.6.sup.-, NO.sub.2.sup.-,
NO.sub.3.sup.-, SO.sub.4.sup.2-, BR.sub.4.sup.-, substituted or
unsubstituted carboranes, substituted or unsubstituted
metallocarboranes, phosphates, phosphites, polyoxometallates,
substituted or unsubstituted carboxylates, triflates and
noncoordinating anions; and wherein R is at least one member
selected from the group consisting of hydrogen, alkyl, substituted
alkyl, cycloalkyl, substituted cycloalkyl, heteroalkyl,
heterocycloalkyl, substituted heterocycloalkyl, aryl, substituted
aryl, heteroaryl, substituted heteroaryl, alkoxy, aryloxy, acyl,
silyl, boryl, phosphino, amino, thio, seleno, and combinations
thereof.
[0070] In other examples, cations that contain a single
five-membered ring free of fusion to other ring structures, such as
an imidazolium cation, are suitable, and the anion of the ionic
liquid can be a halogen or pseudohalogen. For example, a
1,3-di-(C.sub.1-C.sub.6 alkyl or C.sub.1-C.sub.6
alkoxyalkyl)-substituted-imidazolium ion is a suitable cation. The
corresponding anion can be a halogen or pseudohalogen. In addition,
a 1-(C.sub.1-C.sub.6 alkyl)-3-(methyl)-imidazolium [C.sub.nmim,
where n=1-6] cation is also suitable, and a halogen is a suitable
anion.
[0071] Further examples of ionic liquid are ones that are liquid at
or below a temperature of about 200.degree. C. (e.g., below a
temperature of about 150.degree. C.) and above a temperature of
about -100.degree. C. For example, N-alkylisoquinolinium and
N-alkylquinolinium halide salts have melting points of less than
about 200.degree. C. The melting point of N-methylisoquinolinium
chloride is about 183.degree. C., and N-ethylquinolinium iodide has
a melting point of about 158.degree. C. In other examples, a
contemplated ionic liquid is liquid (molten) at or below a
temperature of about 120.degree. C. and above a temperature of
minus 44.degree. C. Still further, a contemplated ionic liquid is
liquid (molten) at a temperature of about minus 10.degree. C. to
about 100.degree. C.
[0072] Further examples of ionic liquids include, but are not
limited to, [C.sub.2mim]Cl, [C.sub.3mim]Cl, [C.sub.4mim]Cl,
[C.sub.6mim]Cl, [C.sub.8mim]Cl, [C.sub.2mim]I,
[C.sub.4mim][PF.sub.6], [C.sub.2mim][PF.sub.6],
[C.sub.3mim][PF.sub.6], [C.sub.3mim][PF.sub.6],
[C.sub.6mim][PF.sub.6], [C.sub.4mim][BF.sub.4],
[C.sub.2mim][BF.sub.4], [C.sub.2mim][C.sub.2H.sub.3O.sub.2].sub.2
and [C.sub.2mim][C.sub.2F.sub.3O.sub.2].
[0073] Illustrative 1-alkyl-3-methyl-imidazolium ionic liquids,
[C.sub.n-mim]X, where n=4 and 6, X=Cl.sup.-, Br.sup.-, SCN.sup.-,
(PF.sub.6).sup.-, (BF.sub.4).sup.-, and [C.sub.8mim]Cl have been
prepared. The dissolution of cellulose (fibrous cellulose, from
Aldrich Chemical Co.) in those illustrative ionic liquids under
ambient conditions with heating to 100.degree. C., with sonication
and with microwave heating, has been examined. Dissolution is
enhanced by the use of microwave heating. Cellulose solutions can
be prepared very quickly, which is energy efficient and provides
associated economic benefits.
[0074] In one example of an ionic liquids and a solution prepared
from such a liquid is substantially free of water or a
nitrogen-containing base. Such a liquid or solution contains about
one percent or less of water or a nitrogen-containing base. Thus,
when a solution is prepared, it is prepared by admixing the ionic
liquid and cellulose in the absence of water or a
nitrogen-containing base to form an admixture.
[0075] A range of different cations can be employed of those
screened from the common sets used to prepare ionic liquids;
imidazolium salts appear to be most effective, with the smallest
imidazolium cation exhibiting the easiest dissolution.
Alkyl-pyridinium salts free of organic base were somewhat less
effective. Smaller phosphonium and ammonium quaternary salts
containing shorter chain alkyl substituents are known, but have
higher melting points and are often not liquid within the
acceptable range for definition as ionic liquids.
[0076] The use of an imidazolium chloride ionic liquid as solvent
for cellulose provides a significant improvement over the
previously-reported solubility of cellulose in the organic
salt/base N-benzylpyridinium chloride/pyridine as discussed in U.S.
Pat. No. 1,943,176, and in which the maximum solubility was 5
weight percent. Indeed, additional nitrogen-containing bases as
were used in that patent are not required to obtain good solubility
of cellulose in the ionic liquids.
[0077] Other ionic liquids include, but are not limited to, those
ionic liquids disclosed in U.S. Pat. No. 6,824,599 and U.S. Pat.
No. 6,808,557, the contents of each being hereby incorporated by
reference in their entireties for at least their teaching of ionic
liquids.
Additives
[0078] Any conventional additive used in polymeric formulations can
be incorporated into the nanomaterials of compositions and methods
disclosed herein. If these additives are incorporated during the
dissolution stage of the resin substrate materials and magnetic
nanoparticulate substances, such additives should not interfere
with the solute-solvent and solvent-solvent interactions. Examples
of conventional additives include, but are not limited,
plasticizers, fillers, colorants, UV-screening-agents and
antioxidants. Other additives include, but are not limited to,
those additives disclosed in U.S. Pat. No. 6,808,557.
EXAMPLES
[0079] The following examples are set forth below to illustrate the
methods and results according to the disclosed subject matter.
These examples are not intended to be inclusive of all aspects of
the subject matter disclosed herein, but rather to illustrate
representative methods and results. These examples are not intended
to exclude equivalents and variations of the present invention
which are apparent to one skilled in the art.
[0080] Efforts have been made to ensure accuracy with respect to
numbers (e.g., amounts, temperature, etc.) but some errors and
deviations should be accounted for. Unless indicated otherwise,
parts are parts by weight, temperature is in .degree. C. or is at
ambient temperature, and pressure is at or near atmospheric. There
are numerous variations and combinations of reaction conditions,
e.g., component concentrations, desired solvents, solvent mixtures,
temperatures, pressures and other reaction ranges and conditions
that can be used to optimize the product purity and yield obtained
from the described process. Only reasonable and routine
experimentation will be required to optimize such process
conditions.
Example 1
[0081] As an example of the operation of the disclosed processes,
the nanoparticles are suspended in a mixture of the ionic liquid
and the resin substrate material, e.g., dissolved cellulose. The
nanoparticles are present in a range of from 2.0 to 30.0 wt %
relative to ionic liquid. The resin substrate material is present
in an amount of from 2 to 20 wt % relative to ionic liquid. The
obtained suspension is placed in an ultrasonic bath for 1 hour,
then degassed in a vacuum oven (e.g., at about 50.degree. C. for
approximately 10 minutes). A 150 Gauss magnetic field is then
supplied using a single magnetic field source or a combination of
magnetic field sources. The resin substrate material is
reconstituted with the nanoparticles captured therein in an aligned
configuration, by contacting with water to remove the ionic liquid
while causing the resin substrate material to reconstitute in solid
form with the nanoparticles encapsulated therein, all while
maintaining the presence of the magnetic field. The contacting with
water can be performed by a variety of methods, such as extrusion
of the mixture in the form of a sheet into water, casting the
mixture into a sheet and washing the sheet with water to remove the
ionic liquid.
[0082] In preferred method for performing the present invention,
the mixture is manually homogenized (to ensure complete mutual
dispersion) and then cast as a film (approximately 1 mm thickness)
on a glass plate using coating rods (R&D Specialties, Weber,
N.Y.). The films are reconstituted and the IL solvent is leached
from the films with deionized (DI) H.sub.2O. Following complete
reconstitution, the film is placed in a bath and immersed in DI
H.sub.2O for at least 24 hours to leach residual IL (such as
[C.sub.4mim]Cl) from the film.
[0083] Other advantages which are obvious and which are inherent to
the invention will be evident to one skilled in the art. It will be
understood that certain features and sub-combinations are of
utility and may be employed without reference to other features and
sub-combinations. This is contemplated by and is within the scope
of the claims. Since many possible embodiments may be made of the
invention without departing from the scope thereof, it is to be
understood that all matter herein set forth or shown in the
accompanying drawings is to be interpreted as illustrative and not
in a limiting sense.
* * * * *