 |
Claims  |
|
|
What is claimed is:
1. A process of forming an electrically conductive blend, solution or
dispersion comprising an electrically substituted or unsubstituted
conductive conjugated polymer dissolved or dispersed in a liquid matrix or
polymeric matrix, said process comprises the steps of:
selecting a matrix liquid or a matrix polymer for the blend, solution, or
dispersion, said matrix liquid or matrix polymer having a first solubility
parameter;
doping a substituted or unsubstituted conjugated polymer having a second
solubility parameter, which is incompatible with said selected matrix
liquid or matrix polymer, with at least one dopant solute to modify the
solubility parameter of said conjugated polymer such that the said second
solubility parameter of said conjugated polymer is closer to said first
solubility parameter of said selected matrix liquid or matrix polymer and
said doped conjugated polymers are compatible; and
dissolving or dispersing said doped conjugated polymer in said liquid or
polymer matrix to form said electrically conductive blend, solution or
dispersion.
2. A process according to claim 1 wherein said conjugated polymer is a
substituted or unsubstituted polyaniline.
3. A process according to claim 2 wherein the polyaniline comprises repeat
units of the Formulas II, III or a combination thereof:
##STR9##
wherein: n and m are the same or different and are integers from 0 to 4
with the proviso that the sum of n and m is 5;
R.sub.1 is phosphinic acid, phosphonic acid, sulfonic acid, boric acid,
phosphoric acid, alkylamino, arylamino, alkylarylamino, sulfonate salt,
borate salt, hydroxy, phosphonate salt, phosphinate salt, phosphate salt,
sulfinic acid, nitro, sulfinate salt, carboxylic acid, halo, carboxylate
salt, cyano, deuterium, or substituted or unsubstituted alkyl, alkenyl,
alkoxy, cycloalkyl, cycloalkenyl, alkanoyl, alkylthio, alkynyl,
dialkylamino, arylamino, diarylamino, alkylarylamino, aryloxy, hydroxy,
alkylthioalkyl, alkylaryl, aryl alkyl, aryloxy, amino, alkylsufinyl,
alkoxyalkyl, alkylsulfonyl, aryl, arylthio, arylsulfinyl, alkoxycarbonyl,
alkylsilane, or arylsulfonyl, wherein permissible substituents are one or
more amino, phosphinate salt, alkylamino, dialkylamino, arylamino,
diarylamino,phosphinic acid, alkylarylamino, phosphonic acid, sulfonic
acid, boric acid, sulfinic acid, sulfinate salt, phosphoric acid,
sulfonate salt, borate salt, carboxylate salt, phosphonate salt, phosphate
salt, carboxylic acid, halo, nitro, hydroxy, cyano or epoxy moieties; or
any two R.sub.1 substituents or any one R.sub.1 substituent and R.sub.2
substituent taken together may form substituted or unsubstituted alkylene,
alkynylene or alkenylene chain completing a 3, 4, 5, 6, 7, 8, 9 or 10
membered aromatic, heteroalicyclic, heteroaromatic or alicyclic carbon
ring, which ring may include one or more divalent ester, carbonyl,
nitrogen, sulfur, sulfinyl, sulfonyl or oxygen, wherein permissible
substituents are one or more amino, alkylamino, phosphinic acid,
phosphinate salt, dialkylamino, arylamino, diarylamino, alkylarylamino,
phosphonic acid, sulfonic acid, boric acid, sulfinic acid, sulfinate salt,
phosphoric acid, sulfonate salt, borate salt, carboxylate salt,
phosphonate salt, phosphate salt, carboxylic acid, halo, nitro, hydroxy,
cyano or epoxy moieties, or R.sub.1 is an aliphatic moiety having repeat
units of the formula:
(OCH.sub.2 CH.sub.2).sub.q O--CH.sub.3, (OCH.sub.2 CH(CH.sub.3)).sub.q
O--CH.sub.3, (CH.sub.2).sub.q CF.sub.3, (CF.sub.2).sub.q (CF.sub.3 or
(CH.sub.2).sub.q CH.sub.3
wherein q is a positive whole number; and
R.sub.2 is the same or different at each occurrence and is R.sub.1
substituents or hydrogen.
4. A process according to claim 3 wherein said polyaniline is of the
Formula IV:
##STR10##
wherein: x and y are the same or different at each occurrence and are
integers equal to or greater than 0, with the proviso that the sum or x
and y are greater than 0;
z is an integer equal to or greater than about 1;
n is an integer from 0 to 3;
m is an integer from 1 to 4, with the proviso that the sum of n and m is 4;
R.sub.1 is the same or different at each occurrence and is alkyl, alkenyl,
alkoxy, cycloalkyl, cycloalkenyl, alkanoyl, amino, alkylamino,
dialkylamino, arylamino, diarylamino, alkylarylamino, alkylthio, aryloxy,
alkylthioalkyl, alkylaryl, arylalkyl, alkylsulfinyl, alkoxyalkyl,
alkylsulfonyl, aryl, arylthio, arylsulfinyl, alkoxycarbonyl, phosphinic
acid, phosphonic acid, alkylsilyl, boric acid, arylsulfonyl, carboxylic
acid, halo, hydroxy, phosphate salt, sulfonate salt, phosphonate salt,
borate salt, phosphinate salt, carboxylate salt, nitro, cyano, sulfonic
acid, phosphoric acid or aryl, alkyl or alkoxy substituted with one or
more sulfonic acid, carboxylic acid, sulfinate salt, phosphoric acid,
boric acid, sulfinic acid, halogen, nitro, cyano, epoxy, hydroxy,
sulfonate salt, phosphate salt, phosphonate salt, phosphinic acid,
phosphinate salt, carboxylate salt, phosphonic acid or borate salt
substituents; or any two R.sub.1 groups or any one R.sub.1 group and
R.sub.2 group together may form a substituted or unsubstituted alkylene or
alkenylene chain completing a 3, 4, 5, 6, 7, 8, 9 or 10 membered
heteroaromatic, heteroalicyclic, aromatic or alicyclic carbon ring, which
chain may include one or more divalent nitrogen, ester, carbonyl, sulfur,
sulfinyl, sulfonyl or oxygen group, wherein permissible substituents are
one or more sulfonic acid, carboxylic acid, sulfinate salt, phosphoric
acid, boric acid, sulfinic acid, halogen, nitro, cyano, epoxy, hydroxy,
sulfonate salt, phosphate salt, phosphonate salts, phosphinic acid,
phosphinate salt, carboxylate salts, phosphonic acid or borate salt
substituents,
R.sub.2 is the same of different at each occurrence and is R.sub.1
substituents or hydrogen.
5. A process according to claim 4 wherein:
m is 2 or 3;
n is 0 or 1;
R.sub.1 is the same or different at each occurrence and is alkyl having
from 1 to about 10 carbon atoms or alkoxy having from 1 to about 10 carbon
atoms;
R.sub.2 is hydrogen or alkyl having from 1 to about 10 carbon atoms;
x is an integer equal to or greater than 1;
y is equal to or greater than 0; and
z is an integer equal to or greater than about 5.
6. A process according to claim 5 wherein R.sub.2 is hydrogen.
7. A process according to claim 4 wherein m is 4 and n is 0.
8. A process according to claim 7 wherein said dopants are acids or acid
derivatives of the formula:
##STR11##
wherein: M is H.sup.+, or other metal or non-metal cation with the proviso
that at least one of M is H.sup.+ or a moiety which can be thermally or
chemically transformed into a proton under use conditions;
t is 0, 1, 2, 3 or 4;
i is 0, 1, 2, 3 or 4;
h is 0, 1, 2, 3 or 4;
c is 0, 1, 2, 3 or 4;
d is 0, 1, 2, 3 or 4;
f is 0, 1, 2, 3 or 4;
g is 0, 1, 2, 3 or 4 with the proviso that at least one of t, i, h, c, d, f
or g is other than 0;
e is 0, 1 or 2; and
R.sub.4, R.sub.5 and R.sub.6 are the same or different at each occurrence
and are nitro, cyano, hydroxy, halo, amino, alkylamino, dialkylamino,
arylamino, diarylamino, alkylarylamino, alkoxy, or substituted or
unsubstituted alkoxy, aryl or alkyl having from 1 to about 30 carbon atoms
wherein permissible substituents include sulfonate salt, perhaloalkyl,
phenyl, alkoxy, halo, cyano, amino, haloalkyl, hydroxy, sulfonic acid,
phosphoric acid, phosphate salt, boric acid, sulfinate salt, phosphinate
salt, sulfinic acid, borate salt, phosphinic acid, phosphonate salt,
phosphonic acid, carboxylic acid, nitro, carboxylate salt, or any two
R.sub.6 or any two R.sub.5 or any R.sub.4 and R.sub.6 substituents
together may form an alkenylene chain completing a fused-ring system which
chain may be unsubstituted or substituted with one or more halo,
phosphoric acid, hydroxy, boric acid, nitro, cyano, amino, sulfinate salt,
phosphinic acid, alkylamino, dialkylamino, phosphinate salt, arylamino,
diarylamino, alkylarylamino, sulfinic acid, phosphate salt, carboxylate
salt, phosphonic acid, phosphonate salt, sulfonate salt, borate salt,
sulfonic acid or carboxylic acid groups, or R.sub.4 or R.sub.5 is a moiety
of the formula:
--(CH.sub.2).sub.q CF.sub.3, --(CF.sub.2).sub.q CF.sub.3,
--(CH.sub.2).sub.q CH.sub.3 --(OCH.sub.2 CH.sub.2).sub.q OCH.sub.3 or
--(OCH.sub.2 CH(CH.sub.3)).sub.q OCH.sub.3
wherein:
q is a positive whole number from 1 to about 10.
9. A process according to claim 8 wherein said dopants are selected from
the group consisting of acids, acid derivatives and mixtures thereof each
of the formula:
R.sub.4 (PO.sub.2 (R.sub.6)M).sub.g (SO.sub.3 M).sub.c (CO.sub.2 M).sub.d
(PO.sub.3 M.sub.2).sub.f
or
##STR12##
wherein: c, d, e, f and g are the same or different and are 0, 1 or 2 with
the proviso that at least one of c, d, and g is not 0;
R.sub.6 is aryl, aryloxy, alkyl or alkoxy;
R.sub.4 and R.sub.5 are the same or different at each occurrence and are
alkyl, phenyl, amino, alkylamino, dialkylamino, arylamino, diarylamino,
alkylarylamino, or alkyl substituted with one or more fluoro, sulfonic
acid, sulfonate salt, alkyxy, carboxylate salt, hydroxy, nitro, cyano,
phosphinic acid, phosphinate salt, amino or carboxylic acid groups, or
phenyl substituted with one or more alkyl, alkoxy, fluoroalkyl, sulfonic
acid, phosphinic acid, phosphinic salt, sulfonate salt, carboxylate,
hydroxy, nitro, cyano, or carboxylic acid groups or any two R.sub.6 or any
two R.sub.5 or any R.sub.4 and R.sub.6 substituents together may form an
alkenylene chain completing a naphthalene anthracene or phenanthrene fused
system which may be substituted with one or more alkyl, alkoxy, fluoro,
phosphinic acid, phosphinate salt, fluoroalkyl, sulfonic acid, sulfonate
salt, carboxylic acid, carboxylate salt, hydroxy, nitro, amino or cyano
groups; and
M is H.sup.+ or other metal or non-metal cation, with the proviso that at
least one of M is H.sup.+ or is a moiety which can be thermally
transformed into a proton under solution conditions.
10. A process according to claim 9 wherein said dopant is a sulfonic acid,
a sulfonic acid derivative, or a combination thereof of the formula:
##STR13##
wherein; c is 1, 2 or 3;
e is 0, 1 or 2;
R.sub.5 is alkyl or alkyl substituted with one or more fluoro, or any two
R.sub.5 groups together may form an alkenylene chain completing a
naphthalene fused system which may be substituted with one more sulfonic
acid, sulfonic acid salt, alkoxy or alkyl; and
M is a proton, or other metal or non-metal cation, with the proviso that at
least one of M is a proton.
11. A process of forming an electrically conductive solid or liquid
dispersion comprised of doped electrically conductive particles of a
conjugated polymer dispersed in a liquid matrix or polymeric matrix, said
process comprising the steps of
selecting a liquid matrix or polymer matrix having a first solubility
parameter;
doping particles of a conjugated polymer which is incompatible with said
selected liquid matrix or polymer matrix to form electrically conductive
particles comprising an ionized electrically conductive conjugated polymer
(polymer cation) doped with one or more dopant solutes (anions), and where
at least one dopant solute predominates at or near the surface of said
particles modifying the solubility parameter, or equivalently the surface
energy, of the conjugated polymer particle at or near the surface of said
particle to enhance the compatibility of the surface of said particle with
said selected liquid or polymer; and
dispersing said particles in said selected liquid matrix or polymer matrix
to form said liquid or solid dispersion.
12. A process according to claim 11 wherein at least a part of said dopant
to be incorporated at or near the surface of said particles is first
incorporated into said selected liquid or polymer matrix in the form of an
acid, salt, or ester thereof.
13. A process according to claim 12 wherein said dopant is reacted and
bonded at or near the surface of said particles during the process of
dispersing said particles in said liquid or polymer matrix. |
|
 |
|
 |
Claims |
|
|
|
Description |
|
|
FIELD OF INVENTION
This invention relates to a process for forming an electrically conductive
solution or dispersion of electrically conductive conjugated polymers in a
liquid or polymeric matrix phase. This invention also relates to the
electrically conductive solutions or dispersions prepared by the process
of this invention and to conductive blends or composites prepared from
said conductive solutions or dispersions, such as conductive parts, films,
coatings, fibers, paints, and inks.
BACKGROUND OF INVENTION
There has recently been an increased interest in the electrochemistry and
electrical phenomena of polymeric systems. Recently, work has intensified
with backbone polymers having extended conjugation in at least one
backbone chain. See for example, U.S. Pat. Nos. 4,855,361; 4,798,685;
4,806,271; 4,822,638; 4,851,487; and 4,798,685; and PCT WO89/01694.
SUMMARY OF INVENTION
This invention relates to a process of forming an electrically conductive
blend, solution or dispersion comprising a substituted or unsubstituted
electrically conductive conjugated polymer dissolved or dispersed in a
liquid or polymeric matrix, said process comprises the steps of:
selecting a matrix liquid or a matrix polymer for the blend, solution, or
dispersion, said matrix liquid or matrix polymer having a first solubility
parameter;
doping a substituted or unsubstituted conjugated polymer having a second
solubility parameter, which is incompatible with said selected matrix
liquid or matrix polymer with at least one dopant solute to modify the
solubility parameter or surface energy of said conjugated polymer to
enhance the compatibility of said conjugated polymer and said selected
matrix liquid or matrix polymer to make the said second solubility
parameter of said conjugated polymer closer the said first solubility
parameter of said matrix liquid or said matrix polymer; and
dissolving, dispersing, or blending said doped conjugated polymer in said
liquid matrix or polymer matrix to form said electrically conductive
solution, dispersion, or blend.
Another aspect of this invention relates to a process of forming an
electrically conductive solid or liquid dispersion comprised of doped
electrically conductive particles of a conjugated polymer dispersed in a
liquid matrix or polymeric matrix, said process comprising the steps of:
selecting a liquid matrix or polymer matrix having a first solubility
parameter;
doping particles of a conjugated polymer having a second solubility
parameter, which polymer is incompatible with said selected liquid matrix
or polymer matrix to form electrically conductive particles comprising an
ionized electrically conductive conjugated polymer (polymer cation) doped
with one or more dopant solutes (anions), and where at least one dopant
solute predominates at or near the surface of said particles modifying the
solubility parameter or the surface energy of said surface with said
selected matrix or matrix polymer to make the second solubility parameter
of said conjugated polymer at or near the surface of said polymer closer
to the said first solubility parameter of said matrix liquid or matrix
polymer; and
dispersing or dissolving said particles in said selected liquid matrix or
polymer matrix to form said liquid or solid dispersion.
In either aspect of this invention, the dopant or dopants intended to
enhance the compatibility of said conductive polymer in said liquid or
polymeric matrix may be optionally first incorporated, all or in part,
within the matrix liquid or polymer in the form of an acid, salt, or ester
which may subsequently react with the conductive polymer during or after
the process of dispersing, dissolving, or blending said conductive polymer
in said matrix.
As used herein, "at or near the surface of the particle" is all or a
portion of the surface of said particles to a depth of about 5 nanometers
(nm); and "at or near the core of said particle" is all or a portion of
the particle more than about 3 nanometers (nm) from the surface of the
particle. As used herein, a "solution" is a real solution or an ultrafine
dispersion having an average particle size of less than about 100
nanometer. As used herein, "incompatible" means that the conductive
polymer in its given state does not form real liquid or solid solutions as
defined above.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, FIG. 1 is a percolation graph of conductivity
versus volume fraction loading (in percent) of polyaniline particles in an
insulating matrix polymer, poly(ethylene terephthalate gycol).
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the first step of the process of this invention, a liquid or polymer is
selected to form the liquid or polymeric matrix. The liquid or polymer has
a solubility parameter. As used herein, "solubility" parameter (.delta.),
which is also known as the Hildebrand parameter, is the square root of the
cohesive energy density of the liquid or solid. The solubility parameter
of useful liquids or polymers may be determined by any suitable means. For
example, solubility parameters can be obtained from suitable handbooks.
The solubility parameter can also be determined through use of
conventional theoretical or empirical methods as for example through
calculation by group contribution methods, or through measuring the degree
of interaction with other liquids or solids with known solubility
parameters. The solubility parameter can also be related to the surface
free energy, or surface tension (y), of the liquid or solid. Such surface
energy can also be used to characterize the matrix material. A better and
more complete description of the matrix is made by determining specific
contributions to the solubility parameter or surface energy as can be
done, for example, by the Hansen Method, as found in "Handbook of
Solubility Parameters and Other Cohesion Parameters" 2nd ed. (by A. F. M.
Barton; CRC Press, 1991 ), wherein the solubility parameter is expressed
according to dispersive (.delta..sub.d), polar (.delta..sub.p), and
hydrogen bonding (.delta..sub.h) contributions where
.delta.=(.delta..sub.d.sup.2 +.delta..sub.p.sup.2
+.delta..sub.h.sup.2).sup.1/2. An analogous expression for the surface
energy is y=y.sub.d +y.sub.p +y.sub.h.
Liquids useful in the practice of this invention may vary widely. The only
requirement is that the liquid is capable of dissolving or dispersing the
required quantity of electrically conductive conjugated backbone polymer.
Preferred liquids have dielectric constants measured at room temperature
(i.e. 10.degree.-30.degree. C.) equal to or greater than 2.2. Illustrative
of such useful liquids are water; dimethylsulfoxide; hydrocarbons such as
hexane, decane, decalin, toluene, xylene, benzene; amides such as
formamide, acetamide, N,N-dimethyl formamide, N,N-dimethyl acetamide,
N-methyl pyrrolidinone, pyrrolidinone, and the like; alcohols and glycols
such as methanol, ethanol, propanol, butanol, pentanol, hexanol, octanol,
glycol, glycerol, propanediol, benzyl alcohol, cresol, phenol,
cyclohexanol, 2-methoxy ethanol, and the like; acids, such as formic acid,
acetic acid, propionic acid, butyric acid, sulfuric acid, trifluoroacetic
acid, pentafluoropropionic acid, perfluorobutyric acid, phosphoric acid,
phosphonic acid, sulfonic acid, and the like; ketones, such as acetone,
2-butanone, 3-pentanone, cyclohexanone, 2,4-pentadione, acetophenone,
benzophenone, methylethylketone, methylisobutylketone, and the like;
amines, such as methylamine, dimethylamine, dipropylamine, triethylamine,
dibenzyl amine, picoline, and the like; nitro compounds of aliphatic and
aromatic hydrocarbons such as nitromethane, nitroethane, nitrobenzene,
nitrotoluene, nitroaniline, tetranitromethane, and the like; nitriles such
as acetonitrile and benzonitrile; halogenated aliphatic and aromatic
hydrocarbons such as methylene chloride, chloroform, chloromethane,
dibromoethylene, trichloroethane, chlorobenzene, o-difluorobenzene,
bromotoluene and the like; esters such as methyl formate, ethyl acetate,
ethyl acetoacetate, methyl benzoate, benzyl acetate, ethyl oleate, butyl
stearate, methyl salicylate, dimethyl phthalate, and the like; ethers such
as methyl ether, ethyl ether, phenyl ether, tetrahydrofuran, 1,4-dioxane,
and the like; phosphates, such as tricresyl phosphate, and the like; and
silicates such as tetraethylsilicate, and the like. More preferred liquids
are those having a relative dielectric constant equal to or greater than
about 3.0 such as water, amides, acids dimethyl sulfoxide, amines,
alcohols, ketones, and nitrohydrocarbons. Particularly preferred liquids
are those having a relative dielectric constant equal to or greater than
about 4.0, such as amides, acids, dimethyl sulfoxide, amines, and
alcohols. The most preferred liquid is an amide, such as substituted or
unsubstituted pyrrolidinone.
Matrix polymers useful in the practice of this invention may also vary
widely. Useful polymeric materials include epoxies, thermoset resins and
thermoplastic polymers. Thermoset polymers for use in the practice of this
invention may vary widely. Illustrative of such useful thermoset polymers
are alkyds derived from the esterification of a polybasic acid such as
phthalic acid and a polyhydric alcohol such as glycol; allylics such as
those produced by polymerization of dialkyl phthalate, dialkyl
isophthalate, dialkyl maleate, and dialkyl chlorendate; amino resins such
as those produced by addition reaction between formaldehyde and such
compounds as melamine, urea, aniline, ethylene urea, sulfonamide and
dicyandiamide; epoxies such as epoxy phenol novolak resins, diglycidyl
ethers of bisphenol A and cycloaliphatic epoxies; phenolics such as resins
derived from reaction of substituted and unsubstituted phenols such as
cresol and phenol with an aldehyde such as formaldehyde and acetaldehyde;
polyesters; silicones; and urethanes formed by reaction of a
polyisocyanate such as 2,6-tolylene diisocyanate, 4,4-diphenylmethane
diisocyanate, 1,6-hexamethylene diisocyanate and 4,4'-dicyclohexylmethane
diisocyanate with a polyol such as polyether polyol (trimethylol propane,
1,2,6-hexanetriol, 2-methyl glycoside, pentaerythitol,
poly(1,4-tetramethylene ether) glycol, sorbitol and sucrose), polyester
polyols such as those prepared by esterification of adipic acid, phthalic
acid and like carboxylic acids with an excess of difunctional alcohols
such as ethylene glycol, diethylene glycol, propanediols and butanediols.
In the case of two component epoxies, hydride-based curing agents are
preferred over amine-based ones.
Thermoplastic polymers for use in the formulation of the composition of
this invention may vary widely. Illustrative of such polymers are
polyesters such as poly(pivaloyl lactone), poly(caprolactone),
poly(para-hydroxybenzoate), poly(ethylene oxybenzoate), poly(ethylene
isophthalate), poly(ethylene terephthalate), poly(butylene terephthalate),
poly(ethylene terephthalate glycol), poly(1,4-cyclohexane dimethylene
terephthalate), poly (ethylene-1,5-naphthalate), poly
(ethylene-2,6-naphathalate) and the like; polyamides such as
poly(4-aminobutyric acid) (nylon 4), poly(6-aminohexanoic acid) (nylon 6),
poly(11 -aminoundecanoic acid) (nylon 11), poly(hexamethylene adipamide)
(nylon 6,6), poly(hexamethylene sebacamide), (nylon 6, 10),
poly[bis(4-aminocyclohexyl)-methane-1,10-decanedicarboxamide
](Quiana)(trans), poly(metaphenylene isophthalamide) (Nomex),
poly(p-phenylene terephthalamide) (Kevlar), and the like; polyethers such
as polyethylene oxide; polycarbonates such as poly[methane
bis(4-phenyl)carbonate], poly[1,1-ethane bis(4-phenyl)carbonate],
poly[4,4-heptane bis(4-phenyl)carbonate], poly
[1,1-(1-phenylethane)bis(4-phenyl)carbonate], poly[diphenylmethane
bis(4-phenyl)carbonate], poly[1,1-cyclohexane bis(4-phenyl) carbonate],
poly[thio bis(4-phenyl)carbonate], poly [2,2-propane bis-[4-(2-methyl
phenyl)]carbonate], poly [2,2-propane bis-[4-(2-chlorophenyl)]carbonate],
and the like; polymers derived from the polymerization of
.alpha.,.beta.-unsaturated monomers such as polyethylene,
acrylonitrile/butadiene/styrene terpolymer, polypropylene,
poly(4-methyl-1-pentene), polyisobutylene, poly(isoprene),
1,2-poly(1,3-butadiene), polystyrene, poly(vinyl chloride),
poly(vinylidene fluoride), poly(vinylidene chloride),
poly(tetrafluoroethylene) (Teflon), poly(chlorotrifluoroethylene),
poly(vinyl acetate), poly(vinyl alcohol), and copolymers thereof such as
poly(ethylene vinyl acetate), poly(ethylene vinyl alcohol), poly(ethylene
acrylic acid), and the like, poly(methyl acrylate), poly(ethyl acrylate),
poly(methyl methacrylate), poly(ethyl methacrylate), polyacrylonitrile,
polyacrylamide and the like; polydienes such as poly(1,3-butadiene) and
the like; polyoxides such as poly
[2,2-bis(chloromethyl)-trimethylene-3-oxide](penton),
poly(2,6-dimethyl-1,4-phenylene oxide) (PPO),
poly(2,6-diphenyl-1,4-phenylene oxide) (Texax, P30) and the like;
polysulphides such as poly(phenylene sulphide) and the like; polysulfones
such as poly[4,4'-isopropylidene diphenoxy di(4-phenylene) sulphone];
Noryl.RTM., and mixtures thereof.
In the preferred embodiments of the invention, the non-conductive
homopolymer or copolymer is a thermoplastic homopolymer or copolymer.
Preferred thermoplastic polymers are polyamides, polyesters,
poly(carbonates), poly(a-olefins), poly(vinyl halides), and copolymers and
terpolymers, such as poly(ethylene terephthalate copolymer and glycol),
acrylonitrile/butadiene/styrene terpolymer. More preferred thermoplastic
homopolymer or copolymers are polyamides, polycarbonates, polyesters and
poly(.alpha.-olefins), and most preferred thermoplastic polymers and
copolymers are poly(ethylene terephthalate glycol), nylon-12,
polyethylene, polypropylene ethylene vinyl acetate (EVA) copolymer,
ethylene vinyl alcohol (EVOH) copolymer, ethylene acrylic acid (EAA)
copolymer, and polystyrene.
In the second step of the process of this invention a conjugated polymer
which is incompatible with the selected matrix liquid or matrix polymer is
doped with a dopant which modifies the solubility parameter of said
conjugated polymer to enhance the compatibility between the doped
conjugated polymer and the matrix liquid or matrix polymer. As used
herein, "compatibility" refers to the extent to which the dopant and the
environment or matrix are compatible and include meeting one or more of
the following criteria: closely matching the solubility parameters and
surface energies, including the Hansen component values of the particle
and the matrix; obtaining low chemical reactivity between the particle and
the matrix or other medium with which the particle will come in contact;
and matching dispersive, polar or hydrogen bonding interactions which will
lead to the facile dispersion of the particles in the matrix. The degree
of compatibility can be assessed by determination of the minimum average
particle size achievable for the conductive polymer dispersed in the
matrix. A small average particle size i.e. equal to or less than 100
nanometers, is indicative of relative compatibility. Full compatibility is
indicated by the formation of a true solution or miscible blend. As used
herein "incompatible" is the opposite of compatible and refers to having a
mismatched surface energy or a chemical reactivity toward the matrix or
the environment in which the doped polymer is dissolved or dispersed.
While we do not wish to be bound by any theory, it is believed that when
the conjugated polymer is doped with a dopant or combination of dopants,
the portion of the dopant(s) which is more compatible with the matrix
liquid or polymer than the conjugated polymer projects away from the
conjugated polymer and renders the combination of dopant and doped
conjugated polymer more compatible with the matrix liquid or polymer than
the more undoped conjugated polymer.
An important requirement for the dopants is that they have a desired set of
averaged solubility parameters which will modify, after coupling to said
conjugated polymer via the doping interaction, the solubility parameters
of said doped conducting polymer to establish a relationship to the
solubility parameters of said solvent or solvent mixture to render said
conductive polymer soluble or dispersible in said liquid solvent, solvent
mixture, solid polymer, polymer "melt" or polymer solution to the desired
extent. The resultant solubility parameter of the doped conjugated
backbone is approximated by the volume fractional sum of the solubility
parameters of the individual components(i.e. the neutral conjugated
backbone polymer and the dopant or dopants), as expressed in the following
equation:
##EQU1##
wherein: .PHI..sub.i is the volume fraction of the i-th component;
.delta..sub.i is the solubility parameter of the i-th component;
X.sub.i is the molar fraction of the i-th component; and
V.sub.i is the molar volume of i-th component.
The molar volume of the i-th component is equal to the ratio of the
molecular weight of the i-th component to the density of the i-th
component.
The value for solubility parameters of the i-th component (.delta..sub.i)
can be found in the Handbook of Chemistry and Physics CRC Press, 67th ed.
1986 and "Handbook of Solubility Parameters and Other Cohesion Parameters"
2nd ed. (by A. F. M. Barton; CRC Press, 1991) and "Polymer Handbook"
(edited by J. Brandrup and E. H. Immergut; John Wiley & Sons, 1989).
Useful methods to estimate the solubility parameter of the i-th component
are the group contribution or empirical methods as disclosed in the
previously mentioned three handbooks.
In cases where one or more dopants predominate on the surface of a
dispersed particle of the conductive polymer, the surface energy and
effective solubility parameter of said particle will be dominated by the
surface energy and solubility parameters characteristic of the part of the
dopant which projects outward from the surface of said particle. In such
an instance, the above described volume fraction approach would not be
appropriate. The action of the dopant in this instance is better treated
as that of a surfactant. Effective solubility parameters for the
lipophilic substituents of common surfactants are tabulated in "Handbook
of Solubility Parameters and Other Cohesion Parameters" 2nd ed. (A. F. M.
Barton, CRC Press, 1991);
The solubility parameter of useful solvents can be determined by any
suitable means. For example, solubility parameters can be obtained from
suitable handbooks as for example the three handbooks mentioned
hereinabove. The solubility parameter can also be determined through use
of conventional methods as for example group contribution methods or
empirical methods.
Whether forming solutions or dispersions, the dopant or dopants intended to
enhance the compatibility of said conductive polymer in said liquid or
polymeric matrix may be optionally first incorporated, all or in part,
within the matrix liquid or polymer in the form of an acid, salt, or ester
which may subsequently react with the conductive polymer during or after
the process of dispersing, dissolving, or blending said conductive polymer
in said matrix. In general, 0 to 100% or the dopant required to fully dope
the conjugated conductive polymer may be incorporated in the liquid or
polymeric matrix. Preferably from about 0 to 20%, more preferably form
about 3 to 20%, and most preferably from about 5 to 15% of the required
dopant is first incorporated in the matrix, and subsequently allowed to
dope the conjugated polymer.
Conjugated polymers for use in the process of this invention may vary
widely. As used herein "conjugated polymers" are homopolymers or
copolymers which are comprised of alternating carbon-carbon double bonds
(either singly or as part of an aromatic ring structure), and optionally
heteroatoms such as oxygen, nitrogen, sulfur, selenium, phosphorous and
the like along the polymer conjugated backbone or conjugated side chains
| | |
