Note: Descriptions are shown in the official language in which they were submitted.
fOLYANILTNE COMPOSITTONS HAVING;
~SLBt~~sr. ~ ~.Q,T~ DQ PB,i~N~ ; EME N T
~K.O~Q31L~~ OF THE INVENTION
1 . ~ ~,e ld Qf t a I~..v~tlt,.~ol1
This invention relates to novel electri~a'_Ly
conductive polyaniline compositions. Another aspect
of this invention relates to polyaniline articles,
including films, fibers. coatings and the like formed
from the polymer compositions of this invention.
2. p~s~riptj,9~ of the Prior Art
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.
One conjugated polymer system currently under
study is polyaniline. Kc~bayashi, et al., ,T_
ElectrQ~l. Chem~, "Electrochemical Reactions
Concerned with Electrochromism of Polyaniline
Film-i.oated Electrodes", LZ 281-291 (1984). describes
various experiments in which spectro electro-chemical
measurement of a polyaniline film coated electrode
were made. French Patent Ne. 1,519,729; French Patent
of l~ddition 94,536; U.K. Patent 1,216,549; "Direct
Current Conductivity of Polyaniline Sulfate", M.
Doriomedoff, F. Rautiere - Cristofini, R. De
Surville, M. Jozefowicz, L-T. Yu, and R. Huvet, sL
Chim,L Phvs. Phvsico~im. ~~~, 58, 1055 ( 1971)
~Continuous Curtent Conduc'_ivity of MacLOmolecular
Materials", L-T. Yu, M. Jozefowicz. and R. fiuvet,
Chim. Macramol, i, 469 (J.97U); "Polyaniline Based
Filmogenic Organic-Conduc:.or Polymers", C. LaDarre
and M. Jozefowicz, C.12. $~aa._~,~.. Ser. C, ~Q, 964
(1969); "Recently discovered Properties of
Semiconducting Polymers", M. Jozefowicz, L-T. Yu, J.
-z-
Perichon, and R. Buvet, ~T_~glym. Sci., Part C
1187 (1969); "Electrochemical Properties of
Polyaniline Sulfates", F. Cristofini, R. De Surville,
and M. Jozefowicz, C.R,_Acad. Ski., SPA. C, ~$, 1346
(1979); "Electrochemical Cells Using Protolytic
Organic Semiconductors", R. De Surville, M.
Jozefowicz, L-T. Yu, J. Perichon, R. Buvet,
Electrochem_. Acta., 1~, 1951 (1968); "Oligomers and
Polymers Produced by Oxidation of Aromatic Amines",
R. De Surville, M. Jozefowicz, and R. Buvet,
Chem. (Paris) ~ 5 (1967); "Experimental Study of the
Direct Current Conductivity of Macromolecular
Compounds", L-T. Yu, M. 8orredon, M. Jozefowicz, G.
Helorgey, and R. Buvet, J. Polvm. Sci. Po .ym. Svmo.,
~, 2931 (1967); "Conductivity and Chemical
Properties of Oligorneric Polyaniline", M. Jozefowicz,
L-T. Yu, G. Belorgey, and R. Buvet, J. o.vm. Sci.
PolytneSSumo. , .1~, 2943 ( 1967) ;, ~Products of the
Catalytic Oxidation of Aromatic Amines". R. De
Surville, M. Jozefowicz, and R. Buvet, Ann. Chim.
(Paris). ~. 149 (1967): "Conductivity and Chemical
Composition of Maeromolecular Semiconductors", Rev.
Gea,. Electr., ~, 1014 (1966); "Relation Between the
Chemical and Electrochemical Properties of
Macromolecular Semiconductors~, M. Jozefowicz and
L-T. Yu, Rev. Gea. Electr., ~ 100B (1966);
"Preparation, Chemical Properties, and Electrical
Conductivity of Poly-N-Alkyl Anilines in the Solid
State", D. Muller and M. Jozefowicz, Bull. Soc.
Che~°~ . Fr. 4087 (1972) .
U.S. Patent Nos. 3,963,496 and 4,025,463
describe oligomeric polyanilines and substituted
polyanilines having not more than S aniline repeat
units which are described as being soluble in certain
organic solvents and which are described as being
useful in the formation of semi-conductors
compositions having bulk electrical conductivities up
3 -
to about 7 x 10'3 S/cm and, surface resistivities of
4 x 107 ohm/square. European Patent No. 0017717 is
an apparent improvement in the compositions of USP
Nos. 3,963,498 and 4,025,463 and states that the
polyaniline can be formed into a latex composite
through use of acetone solutions of the oligomers of
polyaniline and a suitable binder polymer.
U.S. Patent No. 4,855,361 describes a
conductive polymer blend which comprises mixing a
Folyimide with a base-type polymer containing carbon
nitrogen linkages, such as polyaniline, having a
polyimide-like group covalently linked to the
nitrogen atoms of the base-type polymer. The
conductive polymer blend is formed by first reacting
a base-type non-conductive polymer containing
carbon-nitrogen linkages, such as polyaniline, with a
carbonyl anhydride, such as 3,3',9,4'-benzophenone
tetracarboxylic dianhydride to form a conductive
polymer containing polyimide-like groups conveniently
linked to the nitrogen atoms of the base-type polymer
mixing such conductive polymer with non-conductive
polyamide in a suitable solvent. removing the
solvent, and forming a conductive continuous phase
blend of the polyimide and the conductive polymer.
~5 U.S. Patent No. 4,798,685 describes the
production of base-type conductive golymers,
particularly from the family of conductive
polyaniline, by reacting a base-group non-conductive
polymer containing carbon-nitrogen linkages, e.g.
golyaniline,with an R+ donor compound, where R is an
organic group. e.g. methyl iodide, and forming an
electrically conductive polymer in which the R groups
are covalently linked to the nitrogen atoms of the
polymer.
U~S. patent No. 4,806,271 describes the
production of base-type conductive polymers,
particularly from the family of conductive
- 9 -
polyaniline, by reacting a base-type non-conductive
polymer containing carbon-nitrogen linkages e.g.,
polyaniline, with a cation donor compound, such as
R2S04R, R'S02C1 or R"3SiCl, where R, R' and R" are
alkyl or aryl, such as dimethyl sulfate or tosyl
chloride, and forming an electrically conductive
polymer in which the R groups of R2S04 and R'S02
groups of R'S02C1, or the R"3Si groups of R"3SiC1 are
covalently linked to the nitrogen atoms of the
Polymer.
U.S. Patent No. 4,822,638 describes a process
for fabricating an electronic device on a
non-conductive polymer substrate, particularly from
the family of polyaniline, which comprises applying a
covalent doping agent, such as an R+ donor compound,
where R is an organic group, e.g., methyl iodide, to
a preselected portion of a base-type non-conductive
polymer substrate containing carbon-nitrogen
linkages, and converting such preselected portion of
the polymer substrate to an electrically conductive
polymer portion, by covalent linkage of the R groups
of such donor compound. to the nitrogen atoms of the
non-conductive polymer substrate. Electronic
devices, such as resistors, capacitors, inductors.
printed circuits and the like, can be provided by the
invention process, in the form of light-weight
polymers containing no metal,and which are stable and
wherein the conductive portions are non-diffusing.
U.S. Patent No. 4,851,487 describes the
~ production of base-type conductive polymers,
particularly from the family of conductive
polyaniline, by reacting a base-type non-conductive
polymer containing carbon-nitrogen linkages, e.g.,
polyaniline, with an anhydride such as
R-S02-O-S02-R', R-CO-O-CO-R°, R-CO-O-S02R' or
miztures thereof, where R and R' are alkyl or aryl,
e.g., tosylic anhydride or benzophenone
~~~9291
- 5 -
tetracarboxylic dianhydride, and forming an
electrically conductive polymer in which the S02R and
COR groups are covalently linked to the nitrogen
atortis of the conductive polymer and the anion of the
conductive polymers is the S03R' or 02CR' group.
U.S. Patent No. 4,798,685 describes the
production of base-type conductive polymers,
particularly from the Family of conductive
polyaniline, by reacting a base-type non-conductive
Polymer containing carbon-nitrogen linkages, e.g.,
polyaniline, with an R+ donor compound, where R is an
organic group, e.g., methyl iodide, and forming an
electrically conductive polymer in which the R groups
are covalently linked to the nitrogen atoms of the
Polymer. '
PCT W089/01694 describes various of
electrically conductive polyaniline doped with
certain sulfonated dopants materials such as
para-toluene-sulfonic acid. It is disclosed that
these materials ase thermally stable and can be melt
blended with other polymers to form blends.
This invention relates to particles of a
polyaniline doped with two or more dopants where the
dopant at or near the surface of said particles is
different from the dopant at or near the core of said
particles. 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 50A or less,
and "at or near the core of said particle" is all or
a portion of the particle more than about 50A from
the surface of the particle.
Several advantages flow from this invention.
Fox a:ample, through use of this invention, two or
more dopants can be structured in the polyaniline
- 6 -
particles to obtain better properties. For example,
it is critically important to develop more thermally
stable forms of polyaniline which are capable of
being melt blended in matrix polymers with higher
processing temperatures such as nylons and
polycarbonates while at the same time providing a
final blended composition having an acceptable level
of electrical conductivity. WO 90/10297 published
September 7, 1990 and WO 89/101694 published February
23, 1989 identify a broad range of organic acids and
their salts as thermally stable dopants for
polyaniline. However, some of the most thermally
stable dopants such as aryl disulfonates and
trisulfonates of benzene and naphthalene exhibit
significantly lower conductivity as compared to the
less thermally stable dopants such as aryl
monosulfonates. Particles in which the
polyaniline is doped with dopants structured in a
skin/core arrangement (or more generally in a
stratifiQd arrangement) can combine the high
conductivity of one dopant (preferably in the core)
with the high thermal stability of the other dopant
(preferably in the skin) to provide a beneficial
result.
~ variety of other desirable combinations of
properties can b~ achieved through the skin/core or
stratified polyaniline particles. For example, such
particles can be used to enhance the dispersion
ability of polyaniline particles doped in the core
with desirable dopant in a matrix of polymers which is
incompatible with the core dopant. This embodiment of
the invention includes polyaniline particles doped
predominantly in the skin or surface region of the
particle with a dopant which has a more compatible
surface energy with the intended matrix polymer or
polymers of the blend but which may provide less
electrical conductivity and which is doped
- ~ _ 20~92~1
predominantly in the core region with a dopant which
provides higher levels of electrical conductivity.
Other possible desirable features which can be
incorporated via a surface dopant/core dopant
combination is lessening the hygroscopic tendency of
the more electrically conductive core dopant by using
for eaample a fluorinated alkyl sulfonate as the skin
dopant and more high conductive toluene sulfonic acid
as the core dopant. Still other desirable features
which may be incoporated via a surface dopant/core
dopant combination is the lessening of the reactivity
of the doped polyaniline with contacting metals or
with other chemical substances by using a less
reactive surface d'opant such as a polymeric sulfonats,
and using a reactive dopant having a higher le~~el of
electrical conductivity predominantly in the core of
the particle. This arrangement and combination of
dopants provides particles and substrates comprising
conductive polyaniline with the combinations of
desirable features imparted by both dopants whale
minimizing or eliminating the undesirable of each if
taken individually.
ga~~uTpT?nN OF THE P EFERRED EMBODIMENT
HRI QESCRIPTION OF THE DRAWINGS
The invention will be more fully understood and
further advantages will become apparent when
references is made to the following detailed
description of the invention and the accompanying
drawings in which:
Figure 1 is a graph of conductivity half life
measured for a pellet of compressed polyaniline
particles doped with tosylate anions. Measured half
life at various temperatures (solid points) is used to
project half life over a continuous range of
temperature (solid lane).
Figure z is a graph of conductivity half life
versus temperature for a pellet of compressed
polyaniline particles doped with tosylate, and a
combination of tasylate and dodecylbenzene sulfonate
in a skin/core configuration, where in the latter case
the tosylate dopant predominates at the care and the
dodecylbenzene sulfonate dopant predominates at the
skin.
Figure 3 is a graph of half-life versus
temperature for polyaniline particles doped with
tosylate, and a combination of tosylate and 1,5-n
aphthalene disulfonate in a skin/core configuration,
where in the latter case the tosylate dopant
predominates at the core and the naphthalene
disulfonate dopant predominates at the skin.
This invention is directed to particles of a
polyaniline doped with two or more dopants such that
the concentration of at least one dopant at or near
the surface of said particles is higher than the
concentration of at least one other dopant at or near
said core of said particle. Particle size and shape
~ are not critical. Por a:ample, the particles can be
of an irregular shape or can be of a regular or
substantially regular shape. The particles can be
r~gular flat shaped particles having relatively high
aspect ratios or can be short block, spherical, oval
or like shaped particles having relatively low aspect
ratios. In any event, the shape of the particles will
be dictated solely by the needs of the specific
application. Particle size may also vary widely and
is dependent on the particular application. In those
applications Where relatively large particles are
required i.e. 1 to 100 microns, large particles are
used; conversely in those applications where
~~~~2J1
_ g _
relatively small particles are required i.e. less than
about one micron, small particles are used. Although
not ciritcal,usually particle.. size is from about 0.05
to about 50 microns. Preferred particles sizes are
from about 0.02 to about 3 microns. In some
polyaniline compositions particles may exist as
aggregates composed of smaller primary particles. It
is generally most preferred for the production of
uniform blends of high conductivity that these
a99regates be broken down to their primary particles
during compounding. It is most preferred that the
primary particles themselves be doped in a skin/core
configuration and that the primary particles range in
size from about 0.05 to 0.2 microns.
Polyanilines for use in the process of this
invention may vary widely. Any form of substituted
and unsubstituted polyaniline can be conveniently used
in the practice of this invention. Illustrative of
useful forms are those described in Green, A.G. and
Woodhead, A.E., CRVII - Aniline-black and Allied
Compounds, Part II", ,L~ Chem. Soc. , .~Q~, pp. 1117
(1912) and Kobayashi, et al., "Electrochemical
Reactions... of Polyaniline Film-Coated Electrodes",
J. Elect~ganal. Chem.. 177. pp. 281-91 (1984) and in
Shacklette, L.W., et al. "Structure and Properties of
Polyanilin$ as Modeled by Single-Crystal Oligomers",
Ghem. Phvs.. $~,. pp. 3955 (1988), which are hereby
incorporated by reference. Ezamples of unsubstituted
and substituted polyaniline useful in this invention
0 are characterized by different ratios of phenylene
amine and quinone imine backbone segments and include
leucoemeraldine, protoemeraldine, emeraldine,
nigraniline and pernigraniline.
In the preferred embodiments, polyanilines for
use in the invention are polyaniline homopolymers and
copolymers of the type derived from the polymerization
of one or more unsubstituted and substituted anilines
-
of the Formula I:
F'~m~d~~.
wherein:
n is an integer from 0 to 5;
m is an integer from 0 to 5, with the proviso
that the sum of n and m is equal to 5 and with the
further groviso that at least one position on Lhe
aniline ring, preferably at the para position, is
substituted with a substituent which will allow
coupling of the aniline units such halo, hydrozen or
other leaving group;
Rl is the same or different at each occurrence
and is selected from the group consisting of alkyl,
deuterium, alkenyl, alkoay, cycloalkyl, cycloalkenyl,
alkanoyl, alkylthio, arylozy, alkylthioalkyl,
alkylaryl, arylalkyl, amino, alkylamino,
dialkylamino, arylamino, diarylamino, alkylarylamino,
aryl, alkylsulfinyl, arylozyalkyl,
alkylsulfinylalkyl, alkoayalkyl, phosphoric acid.
alkylsulfonyl, arylthio, alkylsulfonylalkyl, boric
acid, phosphoric acid, sulfinate salts, arylsulfinyl,
alkoxycarbonyl, arylsulfonyl, carboxylic acid,
phosphoric acid, halo, hydroay, cyano, sulfinic acid,
carboxylate salts, borate salts, phosphate salts,
sulfonate salts, phosphinate salts, phosphonate '
salts, phosphoric acid, sulfonic acid, vitro,
alkylsilane, or any of the foregoing aryl, aliphatic
or cycloaliphatic groups substituted with one or
more phosphoric acid, sulfonic acid, phosphoric acid,
- 11 -
boric acid, carboxylate salt, borate salt, sulfonate
salt, phosphinate salt, phosphonate salt, phosphate
salt, phosphinic acid, carboxylic acid, halo, nitro,
amino, alkylamino, dia.lkylamino, arylamino,
diarylamino, alkylarylamino, cyano or epoxy moieties;
or any two Rl groups together or any R~ group
together with any R2 group may form a substituted or
unsubstituted alkylene, alkenylene or alkynylene
chain completing a 3, 4, 5, 6, 7, 8, 9 or 10 membered
aromatic, heteroaromatic, heteroalicyclic or
alicyclic ring, which ring may optionally include one
or more divalent nitrogen, sulfur, sulfinyl, ester,
carbonyl, sulfonyl, or o$ygen atoms wherein
permissible substituents are one or more phosphonic
acid, sulfonic acid. phosphoric acid, boric acid,
carboxylate salt. borate salt, sulfonate salt,
phosphinate salts, phosphonate salt, phosphate salt,
phosphinic acid, carboxylic acid, halo, vitro, amino,
alkylamino, dialkylamino, arylamino, diaryiamino,
alkylarylamino, cyano or epozy moieties ; or R1 is an
aliphatic moiety having repeat units of the formula:
-(OCHZCH2)q~-CH3, -(~CH2CH(CH3))q0-CH3,
-(CHZ)q CF3, -(CFZ)q-CF3 or -(CH2)q CH3
wherein q is a positive whole number; and
RZ is selected from the group consisting of
perrtaissibl~ Rl substituents or hydrogen.
Illustrative of the polyanilines useful in the
pts~tice of this invention are those of the Formulas
II to V:
l !!
3s
~.._J
(H)~
- 12 -
ar
(w)~
( 11),~
"°
M t4
1
""~, t
~'t9 n ~ ~'$,~ fl
h
~~Z~n
~P
zo
~ whereinz
n, m, R1 and R2 are as described above;
a and y are the same or different at each
206929.
_ 13 -
occurrence and are integers equal to er greater than
0, with the proviso that the sum of x and y is
greater than 0, preferably x is an integer equal to
or greater than about 1 and/or the ratio of x to y is
greater than or equal to about 0; and
z is the same or different and is an integer
equal to or greater than 1.
The following listing of substituted and
unsubstituted anilines are illustrative of those
which can be used to
prepare polymers and
copolymers
useful in the practice this invention.
of
2-Cyclohexylaniline 2-Acetylaniline
Aniline 2.5-Dimethylaniline
o-Toluidine 2,3-Dimethylaniline
4-Propanoylaniline
2-(Methylamino)aniline 4-Benzylaniline
2-(Dimethylamino)aniline4-Aminoaniline
2-Methyl-9-methozy- 2-Methylthiomethylaniline
carbonylaniline 4-(2,4-Dimethylphenyl)
N-Ethylaniline aniline
4-Carbozyaniline 2-Ethylthioaniline
N-Methyl aniline N-Methyl aniline
2,4-Dimethylaniline
N-Propyl aniline N-Propyl-m-toluidine
N-Hezyl aniline N-Methyl-a-cyanoaniline
m-Toluidine 2,5-Dibutylaniline
o-Ethylaniline 2,5-Dimethozyaniline
m-Ethylaniline Tetrahydronaphthylamine
o-Ethozyaniline o-Cyanoaniline
m-Butylaniline 2-Methylthioaniline
m-Hezylaniline 2,5-Dichloroaniline
m-Octylaniline 3-(n-Butanesulfonic acid)
4-Bromoaniline aniline
2-Bromoaniline 3-Propozymethylaniline
3-Bromoaniline 2,4-Dimethozyaniline
3-Acetamidoaniline 4-Mercaptoaniline
4-Acetamidoaniline 4-Ethylthioaniline
~0~~2~1
- 14 -
5-Chloro-2-methoAy-aniline 3-Phenoxyaniline
S-Chloro-2-ethoxy-aniline 4-Phencayaniline
N-He8y1-m-Toluidine N-Octyl m-toluidine
4-Ph~enylthioaniline 4-Trimethylsilylaniline
3-Amino-9-methylcarbazole 3-Amino carbazole
9-Amino carbazole N-(p-Amino phenyl)
aniline
Illustrative of useful R1 groups are hydrogen,
alkyl, such as methyl, ethyl, octyl, nonyl,
tent-butyl, neopentyl, isopropyl, sec-butyl, dodecyl
and the like, alkenyl such as 1-propenyl, 1-butenyl,
1-pentenyl, 1-hexenyl, 1-heptenyl, 1-octenyl and the
like; alkoay such as propoay, butoay, methoay,
isopropoay, pentoxy, nonoay, ethyoay, octozy, and the
likes cycloalkenyl such as cycloheaenyl,
cyclopentenyl and the like: alkanoyl such as
butanoyl, pentanoyl, octanoyl, ethanoyl, propanoyl
and the like; amino; alkylamino, such as methylamino,
ethylamino, butylamino and the like: dialkylamino,
such as dimethylamino, methylethylamino and the like;
arylamino such as phenylamino, p-methylphenylamino
and the like: diarylamino, such as diphenylamino,
p-nitrophenyl-p'-methylphenylamino and the like;
alkylarylamino, such as 2-phenyl-4-methylamino and
the like: alkylsulfinyl, alkylsulfonyl, alkylthio,
arylthio, arylsulfinyl, and arylsulfonyl such as
butylthio, neopentylthio, methylsulfinyl,
benzylsulfinyl, phenylsulfinyl, propylthio,
octylthio, nonylsulfonyl, octylsulfonyl, methylthio,
lsoprapylthio, phenylsulfonyl, methylsulfonyl,
nonylthio, phenylthio. ethylthio. benzyithio.
phenethylthio, sec-butylthio, naphthylthio and the
like; alkozycarbonyl such as methoaycarbonyl,
ethoaycarbonyl, butoaycarbonyl and the like;
cycloalkyl such as cyclohezyl, cyclopentyl, cyclo-
octyl, cycloheptyl and the like; alkozyalkyl such as
metho$y-methyl, ethozymethyl. butoaymethyl.
15 -
propoxyethyl, pentoxybutyl and the like; aryloxyalkyl
and aryloxyaryl such as phenoxyphenyl, phenoxymethyl
and the like; and various substituted alkyl and aryl
groups such as 1-hydroxybutyl, 1-aminobutyl, 1-
hydroxylpropyl, 1-hydroxypentyl, 1-hydroxyoctyl, 1-
hydroxyethyl, ~-nitroethyl, trifluoromethyl,
3,4-epoxybutyl, cyanomethyl, 3-chloropropyl,
4-nitrophenyl, 3-cyanophenyl, and the like; acid and
acid salts such as sulfonic acid, carboxylic acid and
salts thereof; aliphatic or aryl groups substituted
with an acid or salt thereof such as phosphoric
acid, phosphinic acid, sulfonate salt, sulfinate
salt, sulfonic acid, sulfinic acid, borate salt,
phosphoric acid, boric acid, or carboaylic acid
groups such as ethylsulfonic acid, propylsulfonic
acid, 4-nitro benzene sulfonic acid, butyisulfonic
acid, phenylsulfonic acid, and the like.
Also illustrative of useful R1 groups are
divalent moieties derived from any two R1 groups or a
R1 group with a R2 group such as moieties having from
about 2 to about 7 repeat units of the formula:
-(CR3.CR3-CR3.CR3)_b or -(C(R3)2)a
wherein R3 is the same or different at each
occurrence and as hydrogen or alkyl, as for ezample
-(CH2)~. -(CHZ)g-a -(CH-CH-CH-CH)-,
-ICIiZ-CH(CH~)-CH2l- and -(CH2)5-. and groups
comprised of such moieties which include one or more
heteroatoma of oxygen, nitrogen, ester, sulfonyl,
carbonyl, sulfinyl, and/or sulfur, such as -CH2SCH2-
-CH2NHCH2-. -SCH2NHCH2-, -O-CH2-CH20- -O-CH2-S-CHZ-,
-CH2S(02)CH2-, -CH2S(0)CH2-. -OC(O)CH2CH2-,
-CH2G(O)CH2- and -CH2-O-CH2- to form heterocyclic
amino compounds such as tetrahydronaphthylamine,
dihydrobenzopyrroleamine, benzofuranamine,
dihydrobenzopyranamine, Cihydrobenzofuranamine,
- 16 -
dihydrobenzoparaoxazineamine,
dihydrobenzoparadiazineamine,
dihydrobenzotriazoleamine,
dihydro-benzothiazineamine,benzothiopyranamine,
dihydro-benzoaazoleamine and the like. Exemplary of
useful R3 groups are divalent alkenylene chains
containing 1 to about 3 unsaturated bonds such as
divalent 1,3-butadiene and like moieties which may
also include one or more divalent oxygen, nitrogen,
sulfinyl, sulfonyl, carbonyl, ester, and/or sulfur
groups which form such compounds as
benzodiazineamine, benzodiazoleamine,
benzotriazepine-amine, benzimidazolylamine,
benzisoxazoleamine, benzoaazolylamine,
benzothiazineamine, benzoaazineamine,
naphthaleneamine, benzopyranamine,
benzothiazineamine, anthraceneamine,
aminobenzothio-pyran,aminobenzodiazine,
benzethiopyrone amine, amino-coumarin,
benzthiopheneamine, benzothiodiazoleamine, and the
like.
Exemplary of useful RZ groups are hydrogen and
the above-referenced representative R1 groups
described above such as alkyl as for example, methyl,
ethyl, isopropyl, butyl, isobutyl, hezyl, octyl and
the like; alkylsulfonyl such as methylsulfonyl,
ethylsufonyl, propylsulfonyl and the like;
arylsulfonyl such as phenylsulfonyl, p-methyl
phenylsulfonyl, naphthylsulfonyl and the like.
Preferred for use in the practice of this
invention are polyanilines of the above Formulas II
to V in which:
n is an integer from 0 to about 2;
m is an integer from 2 to 4, with the proviso
that the sum of n and m.is equal to 4;
Rl is aryl, alkyl or alkoay having from 1 to
about 30 carbon atoms, cyano, halo, sulfonic acid,
2~~9~~1
- 17 -
carboxylic acid, boric acid, borate salt, phosphoric
acid, phosphate salt, phosphoric acid, phosphonate
salt, phasphinic acid, phosphinate salt, sulfinic
acid, sulfinate salt, carboxylate salt, sulfonate
salt, amino, alkylamino, dialkylamino, arylamino,
hydroxy, diarylamino, alkylarylamino, or alkyl, ar;~l
or alkoay substituted with phosphoric acid, phosphate
salt, phosphoric acid, borate salt, sulfonate salt,
amino, alkylamino, dialkylamino, arylamino,
diarylamino, alkylarylamino, carboaylate salt,
hydroay, alkoay, phosphoric acid, boric acid, alkyl,
phosphinic acid, phosphonate salt, phosphinate salts,
carboxylic acid or sulfonic acid substituents;
R2 is the same or different at each occurrence
and is a R1 substituent or hydrogen;
a is an integer equal to or greater than 1;
y is equal to or greater than 0,
with the proviso that the ratio of a to y is greater
than about 0.5; and
z is an integer equal to or greater than about
5.
Particularly preferred for use in the practice
of this invention are polyanilines of the above
Formulas in which:
n is an integer from 0 to 1;
m is an integer from 3 to 4, with the proviso
that the sum of n and m is equal to 4;
R1 is aryl, alkyl or alkoay having from 1 to
about 20 carbon atoms, sulfonic acid, halo,
carboxylic acid, amino, carboxylate salt, alkylamino,
phosphonate salt, dialkylamino, arylamino, phosphoric
acid, boric acid, phosphate salt, phosphoric acid,
borate salt, diarylamino, alkylarylamino, or alkyl or
aryl substituted with carboxylic acid, phosphoric
acid, boric acid, phosphate salt, phosphoric acid,
borate salt, sulfonate salt, amino. alkylamino,
dialkylamino, arylamino, diarylamino, alkylarylamino,
~ooo~~~.
_ 18 _
carboxylate salt, halo, phosphonate salt, or sulfonic
acid substituents;
RZ is the same or different at each occurrence
and is a R1 subsituent or hydrogen;
x is an integer equal to or greater than 2;
y is equal to or greater than 0, with the
proviso that the ratio o~ x to y is greater than
about 1; and
z is an integer equal to or greater than about
5~
Amongst the particularly preferred
embodiments, most preferred for use in the practice
of this invention are polyanilines of the above
Formulas III or V in which:
n is an integer from 0 to 1;
m is an integer from 3 to 4, with the proviso
that the surn of n and m is equal to 4;
R1 is aryl, alkyl, alkozy, amino, alkylamino,
dialkylamino, arylamino, diarylamino, alkylarylamino,
halo, sulfonic acid, sulfonate salt, carboxylic acid
or carbozylate salt. ar alkyl or aryl substituted
with one or more sulfonic acid, carbozylate salt.
amino, alkylamino, dialkylamino, arylamino,
diarylamino, halo, alkylarylamino, sulfate salt,
sulfonate salt, or carboxylic acid substituents,
wherein the aromatic moieties include from 6 to about
21 carbon stoma and the aliphatic moieties include
from 1 to about 15 carbon atoms;
RZ is hydrogen;
z is an integer equal to or greater than 2;
y is equal to or greater than l, with the
proviso that the ratio of z to y is equal to or
greater than about 2; and
z is an integer equal to or greater than about
5.
In the most preferred embodiments of this
invention, the polyaniline is derived from
19 - 20692~~.
unsubstituted aniline, alkoxy, alkyl, or sulfonic
acid substituted aniline or copolymers thereof.
In general, the number of aniline repeat units
is not critical and may vary widely. The greater the
number of aniline repeat units the greater the
viscosity and molecular weight of the polyaniline.
In those applications where a polyaniline of lower
molecular weight and viscosity is required, such
material may be used, and in those applications where
a polyaniline of high molecular weight and viscosity
is required, then such material can be used. The
number of aniline repeat units is preferably at least
about 10. The upper limit can vary widely depending
on the desired viscosity and molecular weight. In
the more preferred embodiments of the invention, the
number of aniline repeat units is at least about 20,
and in the particularly preferred embodiments. the
number of repeat units is at least about 30. Amongst
the particularly preferred embodiments, most
preferred are those embodiments in which the number
of repeat units is at least about 40.
Useful polyanilines can be prepared through
use of chemical and electrochemical synthetic
procedures. For example, one form of polyaniline can
be prepared by treating aniline with ammonium
persulfate (P1H4)ZS208 in excess 1M HC1. This
powdared form of polyaniline is blue green in color.
After methanol washing and air drying this material
exhibits a conductivity of 10 S/cm. This conductive
form of polyaniline can be treated with ammonium
hydroxide in ethanol to form a non-conductive form of
polyaniline which is purple in color and which has a
conductivity of less than 10'8 S/cm. Other chemical
procedures for preparation of various chemical forms
of polyaniline are described in detail in Green et
al. described above.
~~~~~~1
- 20 -
Useful forms of oolyaniline can also be
prepared electrochemically. For example, useful
forms of polyaniline can be prepared by the
electrochemical oxidation of aniline in aqueous
fluoroboric acid electrolyte on a platinum foil anode.
Other chemical and electrochemical syntheses
and transformations of the conductive form of
polyaniline may be discovered and are presently
contemplated as being useful. Moreover, additional
forms or types of polyaniline may be elucidated in
the future. Accordingly, no limitation to the
syntheses, transformation, or structures herein
described or postulated is intended beyond the
limitations of the appended claims.
The polyaniline may be electrically neutral or
electrically conductive polyaniline may be used.
Polyaniline is rendered electrically conductive by
doping with a dopant solute. In general, such dopant
solute is derived from a compound, which upon
addition to the polyaniline. ionizes the polymer with
co-committent formation of a dopant solute species to
form a charge transfer complex with polyaniline,
which complex has a conductivity equal to or greater
than about 10-6ohm-1Cm-1 by the four-in-line probe
method.
Dopants for use in the practice of this
invention can vary widely and can be such materials
which are known in the art for use in doping
conjugated backbone polymers to form conductive or
semi-conductive polymers, as for eaample, those
described in detail in U.S. Patent Nos. 4,442,187 and
4,321,114 which are hereby incorporated by
reference. Illustrative of useful dopant species are
oxidizing dopants. Oxidizing dopants are well known
in the conductive polymer art, and any of such known
oxidizing dopants can be used.
2f~~9~91
- 21 -
Illustrative of useful oxidizing dopants are
AsFS, Mo0C14, MoCls, PC15, POC13, PC13, A1C13, NO+
and NOZ'" salts (such as NOBF~, NOPF6, NOSbF6, NOAsF6,
NOCH3C0z, N02BF4, N02PF5, NOZAsF6, N02SbF6, and
N02CF3S02), HC104, HN03, HZSOg, benzoylperoaide, S03,
Hr2, (FS03)Z, ZnCl2, FS03H, and Fe(III) salts (such
as Fe(BF4)3, FeBr3, Fe(CH3S03)3. Fe(C104)3, FeCl3.
Fe(OTs)3, and Fe(CF3SO3)3 which give rise to doped
polymers containing dopant solutes such as N03-,
CH3S03-, A1C14-,BF4-, ZnCl4-, PC14-. PF6-, AsF6-,
SbF6', CF3S03-, C104-. OTs-, S03'Z, C6HSC02-,
CH3S03-, FS03', and FeClg°. Other useful oxidizing
dopants include electrolyte salts such as
LiCIO4,LiBF4, LiAsF6, NaPF6, BuqNC104, Bu,~NOTs,
BuqNCF3S03, LiCF3S03, AgOTs, and the like. Preferred
oxidizing dopants for use in the practice of this
invention are oxidizing dopants selected from the
group consisting of MoOCl4, MoClS, PC1S, POC13. and
Fe (TII) salts such as Fe(C10~)3, FeCl3, FeBr3, and
Fe(CF3SO3)3, and particularly preferred oxidizing
dopants for use in the practice of this invention are
dopants selected from the group consisting of MoOCl4.
MoClS, PC1S, POC13, FeBr3 and FeCl3. Amongst these
particularly preferred embodiments, most preferred
2S oaldizing dopants are those embodiments in which the
oxidizing dopant is FeCl3.
Illustrative of other dopants are inorganic
oxidizing or non-oxidizing protonic acid dopants.
Such dopants include inorganic acid such as
hydrofluoric acid, hydrochloric acid, hydroiodic
acid, phosphoric acid, nitric acid, perchloric acid,
boric acid, sulfuric acid and the like.
Illustrative of still other useful dopants are
non-oxidizing protonic acids such as those of
3S containing anionic moieties of the formula:
R~(PO3°)r(POZ(R6)-)r(BO2°)r(so3-)r
(C02-)r(POZ°)r PO(Rg) )(SO2 )r
209291.
22 -
and having one or more cationic moieties selected
from the group consisting of:
M+s
wherein:
R4 and R6 are the same or different at each
occurrence and are organic radical or amino;
M is a species having a positive charge equal
to s, provided that at least one of M+s is a proton
or a moiety which can be transformed by radiation,
heat, chemicals and the like into a proton under use
conditions such as +NH4, +N(cH3)2H2, +N(C2HS~H3 and
the like;
s is the same or different at each occurrence
and is an integer equal to 1 to 8;
r is the same or different at each occurrence
and is 0 or a positive integer equal to or greater
than I, with the proviso that at least one of r is
other than 0.
The R4 and R6 group may vary widely and can be
a substituted or unsubstituted aliphatic radical such
as alkyl, nitroalkyl, haloalkyl and the like, or a
substituted or unsubstituted aromatic radical such as
phenyl, helophenyl, nitrophenyl, anthracyl, naphthyl,
phenanthryl and the like. RQ and R6 groups may also
be s polymeric radical such as a polymer having
reGUrring pendant phenyl groups in the polymeric
backbone substituted with sulfonic acid and
derivatives thereof such as salts, phosphoric acid and
derivatives thereof such as salts, phosphoric acid and
derivatives thereof such as salts. sulfinic acid and
derivatives thereof such as salts, carboxylic acid and
derivatives thereof such as salts, boric acid and
derivatives thereof such as salts, or phosphoric acid
and derivatives thereof such as salts; moieties such
- 23 -
as sulfonated or phosphonated polystyrene,
poly(a-methylstyrenN), poly(4-phenylstyrene),
poly(2-vinyl naphthalene), polyvinyl benzoate),
poly(benzyl methacrylate) and the like. In the
particularly preferred embodiments of the invention,
Rq and R6 are aromatic radical and in the most
precerred embodiments R4 and R~ are substituted or
unsubstituted phenyl or naphthyl. The nature of the
M+n group may vary widely. For example, M+n may be be
a non-metal ration such as Bu~N+, H+, NO+, NO2~, NH4~,
+N(CH3)2H2, +N(C2H~)H3, and the like, or may be a
metal ration such as Na+, Li+, Ag+, Ha+2, Co+3, A1+3,
Fe+3 and the like.
Preferred for use in the practice of this
invention are organic acid dopants, more preferably
those having anionic moieties of the formulas:
R4(P03')r(P02')r(S02-)r{P02(R6)')r{S03)')r(C02-')r
(PO(R6)")(B02')r
and having a cationic moiety of the Formula:
M+s
wherein at least one of the cationic moieties of the
formula M+s is a proton or is a moiety which can be
transformed into a proton under use conditions;
M+s is a cationic species having or positing
charge s;
s is an integer equal to or greater than 1,
preferably from 1 to about 8;
R4 and R6 are organic radicals or amino, and
r is an integer equal to or greater than 1,
preferably from 1 to about 8;
More preferred for use in the practice of this
invention as dopants are acids or acid derivatives of
~~~~~~1
- 29 -
the formula:
Rq(POZ(R6)M)g(P03M')f(S03M)c(COZM)d(POZM2)t(SOZM)h
S (PO(R6)M)i
or
S°aM~r, ~-R5~ ~
a~ ~~ ~ ~ C.P
(~~p3/r~~~5o3M ~ c.
wherein:
hi is H+. or other metal or non-metal cation
with the proviso that at least one of M is H+ or a
moiety which can be thermally or chemically
transformed into a proton under use conditions, such
as +NH4,+N(CH3)2H2, +N(C2H5)H3 and the like
t is 0, 1, 2, 3 or 4;
h is l, 1, 2, 3 or 4;
i is 1, 1, 2, 3 or 4;
c is 0, 1. Z, 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 c, d, f, g, h, i or t is other than 0;
a is 0, 1 or 2; and
R4 and R5 are the same or different at each
occurrence and are nitro, cyano, hydroay, halo, amino,
alkylamino, dialkylamino, arylamino, diarylamino,
alkylarylamino, alkozy, or salt substituted or
unsubstituted alkozy, aryl or alkyl having from 1 to
2~~~291
_ zs -
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, vitro, carboaylate salt and the like,
or any two R4 or any two RS 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, hydroay, boric
acid, vitro, cyano, amino, sulfinate salt, phosphinic
acid, alkylamino, dialkylamino, ghosphinate salt,
arylamino, diarylamino, alkylarylamino, sulfinic acid,
phosphate salt. carbozylate salt, phosphonic acid,
phosphonate salt, sulfonate salt, borate salt,
sulfonic acid or carboaylic acid groups, or R4 or R5
is a moiety of the formula:
-(CH2)qCF3, -(CFZ)qCF3, -(CHZ)qCH3
-(OCH2CH2)qOCH3 or -(OCH2CH(CH3))qOCH3
wherein:
g is a positive whole number from 1 to about
10; and
R~ is alkyl, aryl, aryiozy or alkoxy.
In the particularly preferred embodiment of
this invention, useful dopants are acids andlor acid
derivatives of the above formula:
R4(POZ(R6)M)g(PO~M2)f(SO3M)c(C02M)d(P02M2)t(SO2M)h
(PO(R6)M)i
or
2~ _ ~0~9291
S°~~~r, ~-Rs~ ~
Lpp~ ~'~3M~~~r
~~.~3m~~Lso~M ~
wherein:
c is 0, 1, z or 3;
d, t, f, g, h and i are the same or different
at each occurrence and are with the proviso that at
least one of c, d, t, f of g, i or h is other than 0;
a is 0, 1 or 2;
R~ and RS are the same or different are
hydroay, amino, alkylamino, dialkylamino, arylamino,
diarylamino, alkyl aryl amino, substituted or
unsubstituted phenyl or alkyl wherein permissible
substituents are selected from the group consisting
of alkyl, hydroay, amino, alkylamino, dialkylamine,
arylamine, diarylamino, alkylarylamino, hydroay,
phenyl, haloalkyl, perhaloalkyl, cyano, amino, vitro,
alkoay, boric acid, borate salts, phosphonate,
~ phosphonic acid. carbozylate salts, sulfonate salts,
phosphate salts, phosphinic acid, phosphinate salt,
sulfonic acid, carboaylic acid, phosphoric acid,
sulfinic acid or sulfinate salts or any two R6
substituents together may form an unsubstituted or
substituted or alkenylene chain completing a
naphthalene, anthracene or phenanthracene fused ring
system wherein permissible substituents are as
described above or RQ or RS is a moiety of the
formula:
-(CH2)qCF3,-(CFZ)gCR3,-(CH2)qCH3,
-(OCHZCH2)gOCH3 or -(OCH2CH(CH3))q OCH3
- ~~ - 2a~9291
wherein:
q is a positive whole number from 1 to about
10;
R6 is alkyl, alkoxy, arylosy or aryl; and
M is H+, or other metal or non-metal cation,
with the proviso that at least one of M is H+ or a
moiety which can be thermally or chemically
transformed into a proton under use conditions.
zn the most preferred embodiments of this
invention, useful dopants are acids and/or acid
derivaties of the formula:
RQ(P02(R6)M)g(P03M2)f(S03M)c(C02M)d
Or
20
~~~a
oa"'~~ ~. ~ _.
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, f and g is not 0;
R4 and RS 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, alkozy, carbozylate
salt, hydrozy, nitro, cyano, phosphinic acid,
.- 28 -
phosphonic acid phosphinate salt, phosphonate salt,
amino or carboxylic acid groups, or phenyl
substituted with one or more alkyl, alkoxy,
fluoroalkyl, sulfonic acid, phosphinic acid,
phosphonic acid, phosphinate salt, phosphonate salt,
sulfonate salt, carboxylate, hydroxy, vitro, cyano,
or carboxylic acid groups or any two R4 or R5
substituents together may form an alkylene or
alkenylene chain completing a naphthalene, anthracene
LO or phenanthracene fused system which may be
substituted with one or more alkyl, alkoxy, fluoro,
phosphinic acid, phosphinate salt, phosphonic acid,
phosphonate salt, fluoroalkyl, sulfonic acid,
sulfonate salt, carboaylic acid, carbo:ylate salt,
hydroay, vitro, amino or cyano groups;
R6 is aryl, aryloay, alkyl or alkozy; and
M is H+ or other metal or non-metal cation,
with the proviso that at least one of M is H+ or is a
moiety which can be thermally transformed into a
proton under process condistions.
In the especially preferred embodiments of
this invention, useful dopants are acids or acid
derivaties of the formula:
Rq(S03M)c (OOZ1~I)d
or
C
~3r~~~
3S
- 29 -
wherein:
c is i, 2 or 3;
d is l, Z or 2 with the proviso that at least
one of c, d is not 0
a is 0, 1 or 2;
R4 and RS are the same or different at each
occurrence and are hydroxy, dialkylamino,
l0 diarylamino, alkylarylamino, amino, alkylamino,
arylamino, alkyl, phenyl, alkyl substituted with one
or more fluoro, sulfonic acid, sulfonate salt,
alkoxy, dialkylamino, diarylamino, alkylarylamino,
carboxylate salt, hydroxy, alkylamino, arylamino,
15 phosphonic acid, nitro, cyano, phosphinic acid,
phosphinate salt, phosphonate, amino or carboxylic
acid groups, or phenyl substituted with one or more
alkyl, alkoxy, fluoroalkyl, dialkylamino,
diarylamino, alkylarylamino, sulfonic acid,
2o alkylamino, arylamino, sulfonate salt, carboaylate
salt, hydroxy, phosphinate acid, phosphinate salt,
nitro, cyano, amino or carboxylic groups or any two
R4 and RS substituents together may form an alkylene
or alkenylene chain completing a naphthalene,
anthracene or phenanthracene fused system which may
be substituted with one or more alkyl, alkoay,
fluoro, fluoroalkyi, sulfonic acid, sulfonate salt,
carboxylic acid, phosphinic acid, phosphinate salts,
carboxylate salt, hydroxy, nitro, amino, alkylamino,
dialkylamino, arylamino, diarylamino, alkylarylamino,
or cyano groups;
M is Hø or other metal or non-metal cation or
a moiety which can be thermally tranformed into a
proton under process conditions.
In the process of the embodiment of this
invention of choice, the dopant is a sulfonic acid or
sulfonic acid derivative of the formula:
~~(~~~~~
_~o~
to
wherein;
c is 1. 2 or 3;
a is 0, 1 or 2;
R5 is alkyl or alkyl substituted with one or
15 more fluoro groups, or any two RZ groups together may
form an alkenylene chain completing a naphthalene
fused ring system which may be substituted with one
or more sulfonic acid, sulfonic salt group or a
combination thereof; and
20 M is a proton, or other metal or non-metal
can on, with the proviso that at least one of M is
proton.
The following is a listing of dopants which
are useful in the practice of the most preferred
2S embodiments of this invention for formation of the
dopant solute.
1-anthracene sulfonic acid,
9-anthracene sulfonic acid,
Z-phenanthracene sulfonic acid,
30 3-phenanthracene sulfonic acid,
9-phenanthracene sulfonic acid,
N02CF3S03.
CF3S03H,
perflouro octyl sulfonic acid
35 Perfluoro octyl carboxylic acid
octylsulfonic acid.
dodecylsulfonic acid,
2~~~?~1
- 31 -
cetylsulfonic acid,
roluenesulfonic acid (TsOH),
Fe{OTs)3,
Fe(CH3S03)3~
(FS03)',
AgOTs,
Me3Si0Ts,
dodecylbenzene sulfonic acid,
naphthalene sulfonic acid,
benzene disulfonic acid,
benzene sulfonic acid,
1,3-benzene disulfonic acid,
2,5-dihydroay-1,~-benzene disulfonic acid,
camphor sulfinic acid
naphthalene trisulfonic acid
dodecylbenzene sulfonic acid,
ethane sulfonic acid
1,5-naphthalene disulfonic acid,
nickel phthalocyanine tetrasulfonic acid,
phenyl phosphoric acid.
diphenyl ghasphinic acid
phenyl phosphinic acid,
3-sulfopropyl acrylate.
3-sulfopropyl methacrylate,
sulfamic acid,
5-sulfosalicyclic acid,
trion (4,5-dihydroay-1,3-benzene disulfonic
acid),
vinyl sulfonic acid.
sulfanilic acid,
4-sulfophthalic acid,
sulfoacetic acid,
methyl phosphinic acid,
phenylphosphonic acid.
3S methyl phosphoric acid,
methyl orange,
sulfonated polystyrene,
- 32 -
sulfonated poly(2-vinyl naphthalene),
naphthol yellow,
naphthal blue black,
1,2-naphthoquinone-4-sulfonic acid,
naphthylazoxine S,
1-octane sulfonic acid,
t-butyl phosphoric acid,
ethyl phosphoric acid,
butyl phosphoric acid,
1,2-benzene disulfonic acid,
4-octylbenzene sulfonic acid,
2-mesitylene sulfonic acid,
2,6-naphthalene disulfonic acid,
2-naphthalene sulfonic acid,
1,3,6-naphthalene trisulfonic acid,
1,3,7-naphthalene trisulfonic acid,
sulfonazo III acid, -
biphenyl disulfonic acid,
biphenyl sulfonic acid,
1.8-dihydroaynaphthalene-3-6-disulfonic acid,
3,6-dihydroaynaphthalene-2,7-disulfonic acid,
4,5-dihydroaynaphthalene-2,7-disulfanic acid,
6,7-dihydroay-2-naphthalene sulfonic acid,
1-naphthalene phosphoric acid,
1-naphthalene sulfonic acid,
1-naphthalene-5,7-dinitro-8-hydroay,
1-naphthalene-4-hydroxy sulfonic acid,
4-bromo benzene sulfonic acid,
4-hydro$y-5-isopropyl-2-methyl benzene
sulfonic acid
3,4-diamino benzene sulfonic acid
benzenephosphoric acid,
1,3.5-benzene trisulfonic acid,
2-methyl-5-isopropyl benzene sulfonic acid,
3,~-dinitro benzene sulfonic acid,
2-methoay benzene sulfonic acid,
1-naphthalene-5-hydroay sulfonic acid,
-- 33
1-naphthalene-7-hydroxy sulfonic acid,
1-naphthalene-3-hydroxy sulfonic acid,
2-napthalene-1-hydroxy sulfonic acid,
~-phenylamino benzene sulfonic acid,
1,6-naphthalene disulfonic acid,
1,5-naphthalene disulfonic acid,
1,3-naphthalene-7-hydroxy disulfonic acid, and
Me3SiOSO2CF3.
L'opants which are preferred for use at or near
the core of the conductive polyaniline particles of
this invention when the purpose is to achieve high
conductivity include but or not limited to:
methane sulfonic acid,
trifluoromethane sulfonic acid,
P-toluene sulfonic acid,
4-hydroaybenzene sulfonic acid,
benzene sulfonic acid,
perchloric acid,
sulfuric acid, and
trifluoroacetic acid.
Dopants which are preferred for use in this
invention at or near the outer surface layer of the
polyaniline particles of this invention when the
purpose is to achieve increased compatibility between
the conductive polymer particles and a matrix polymer
of lower surface energy and lesser polar character
include those which contain one or more alkyl or
fluoroalkyl substituents of length equal t~ or
greater than about 2 carbon atoms, preferably equal
to or greater than about 5 carbon atoms, more
preferably equal to or greater than about 8 carbon
atoms, and most preferably equal to or greater than
12 carbon atoms. Such dopants include but are not
limited to:
octylsulfonic acid,
perfluorooctylsulfonic acid,
dodecylsulfonic acid,
3~ - ~O~i~~~l
dodecylben2enesu.lfonic acid,
dinonylnaphthalenesulfonic acid and
dodecyldiphenyl ether disulfonic acid.
The latter is available from Dow Chemical Co. as
DOWFAX 2AO.T~. Such dopants are also capable of
lessening the hygroscopic nature of the polymer
particles.
Dopants which are preferred for use at or near
the outer surface layer or surface layers of the
Particles of this invention when the purpose is to
obtain more thermally stable compositions are organic
sulfonic acids containing more than one sulfonic acid
group including disulfonates such as
1,5-naphthalene sulfonic acid,
2,6-naphthalene sulfonic acid,
dodecyldiphenyl ether disulfonic acid
1-naphthol-3,6-disulfonic acid,
diphenylether-4,4'-disulfonic acid,
diphenylsulfone-4,4'-disulfonic acid, and
2.5-dihydroay-1,4-benaene disulfonic acid.
Also preferred as thermally stable dopants for
use at or near the outer surface of the particles of
this invention are organic sulfonates including
oligomer and polymeric sulfonates containing more than
two sulfonic acid groups such as
1.3.6-naphthalene trisulfonic acid,
polyvinyl sulfonic acid,
sulfonated polystyrene,
sulfonated poly(4-vinyl naphthalene), and the
like.
The amount of dopant added to the polyaniline at
or near the surface of the particle or at or near the
core of the particle is not critical and may vary
widely. In general, sufficient dopant is added to the
polyaniline such that the conductivity of at least
about 10-g ohm-lcm-1. The upper level of conductivity
is not critical and will usually depend on the type of
aniline polymer employed and the dopant. In general,
the highest level of conductivity that can be obtained
_ 35 _
is provided without unduly adversely affecting the
environmental stability of the polyaniline. In the
preferred embodiments of the invention, the amount of
dopant employed is sufficient to provide a
conductivity of at least about 10"6ohm"'lcm-1 and in
the particularly preferred embodiments is sufficient
to provide a conductivity of from about 10'4ohm°lcm'1
to about 10+3ohm°lcm°l. Amongst these particularly
preferred embodiments, most preferred are those
embodiments in which sufficient dopant is employed to
provide a conductivity of at least about 10'3ohm°lcm'1
to about 10+3ohm'lcm'l, with amounts sufficient to
provide a conductivity from about 100ohm'lcm'1 to
about 10~3ohm"lcm"1 usually being the amounts of
choice.
The region or portion of the particles doped by a
particular dopant and the selected dopant are
critical. In general, the area at or near the surface.
of the particle is predominantly doped with a dopant
that is "compatible" with the environment or matrix in
which the particles will be dispersed and/or the
conditions under which said particles will be
dispersed. As used herein "compatibility" refers to
the eztent to which the dopant and the environment or
matriz are misicible and include meeting one or more
of the following criteria: closely matching the
cohesive energies 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 maximizing
dispersive polar or hydrogen bonding interactions
which will lead to the facile dispersion of the
particles in the matrix. Additionally, when two or
more dopants are employed it is generally preferred
that the dopant at or near the surface be the most
thermally stable of the dopants. The region of the
particle at or near the core of the particle is doped
2~~~2,~1.
-- 3 6
with any kind of dopant, but is preferably doped with
a dopant or mixture of dopants, which offers high
conductivity and/or high thermal stability. The
dopant within the core can be "incompatible" with the
environment in which the particle is used or is
adversely affected by such environment (reduction in
beneficial properties) to any extent. As used herein,
"incompatible" is the opposite to compatible and
refers to having a mismatched surface energy or a
chemical reactivity toward the matrix or the
environment in which the particle is embedded. When
more than two dopants are to be employed in a
multilayer structure it is preferred that the dopant
in the outer most layer be the most compatible with
the matrix, the dopant in the neat outermost layer
produce the most thermally stable doped polymer, and
the dopant in the innermost layer offer high
conductivity or other advantages in the use or
synthesis of the conductive polymer particles of this
invention.
This degree of structure provides for an increase
in the effectiveness of the particles under use
conditions. For example, highly dispersible high
conductivity particles with high thermal stability are
sought for dispersion in higher temperature
thermoplastics, such as polyethylene terephthalate),
polyethylene terephthalate glycol), nylon 6, nylon
66, polycarbonate, poly(phenylene oxide), and the
lilts. When such blends are used, for example, to
provide electromagnetric interference (EMI) shielding,
a blend conductivity greater than about 0.1 S/cm is
usually required and a blend conductivity of greater
than 1.0 S/cm is preferred. Uniform distribution of
particles is sought to prevent gaps in the shield.
Surfaces and corners in molded articles typically
present difficulties for achieving sufficiently
uniform distribution of particles. The present
37
invention provides means for achieving the desired
properties of the blend by providing conductive
particles which by virtue of their multilayer
structure preferably combine the requirements for
compatibility, thermal stability, and high
conductivity.
Similarly, the present invention provides a means
of providing dispersible particles of a desirable
size, geometry, and surface area. Such particles are
generally produced by a nucleation and growth process
within the reaction mixture. The size, shape, and
surface area of such particles is known by those of
skill in the art to be a function of reaction
conditions especially including the chemical
1S composition of the dopant which is typically present
during the synthesis of the polyaniline. The present
invention allows for the optimal choice of dopant for
this purpose since the other required characteristics,
compatibility with the matriz and thermal stability,
z0 can be added or enhanced in a post synthesis via a
controlled exchange of dopant(s) in the surface
regions of the particles. While we do not Wish to be
bound by any theories. we postulate that the loss of
conductivity from regions containing thermally
unstable doped polyaniline compositions frequently
occurs via outward diffusion and/or evaporation of the
dopant. The use of a thermally stable dopant in an
outer layer of the particle prevents or slows the loss
of dopant from within the particle by limiting the
3,0 outward diffusion of such dopants of lower thermal
stability. The particles may include various other
optional ingridients. For example, salts containing
dopant anions. plasticizers, or dispersion aids.
The particles of this invention can be
35 manufactured using modification of conventional
chemical or electrochemical doping procedures such as
those of U.S Patent 4,820,595 relating to polyaniline
_ 3g _
which is hereby incorporated by reference. For
example, particles of pcly~niline can be prepared by
addition of an oxidant to solutions of the aniline
monomer, The dopant anion incorporated in the
poiyaniline may be derived from the oxidant (e. g.
FeCl4- from FeCl3) or it may be derived from an acid
or salt which is also present in the solution (e. g.,
CH3(CSH4)S03- when tosylic acid is present) during
addition of an oxidant such as ammonium persulfate.
Such conventional procedures produce doped conductive
polyaniline particles and particle aggregates which
are in general homogeneously doped with a dopant or
mixture of dopants. In the present invention, such
dopants or mixtures of dopants form the core of the
conductive polyanilines particles. The outer layer or
layers of the particles of this invention which
contain dopant produced either during synthesis or
after synthesis by dopant ezchange or by partial
dopant removal and replacement. It is possible to
achieve a stratified dopant configuration by using an
excess of a different salt or acid during the latter
stages of the polymerization reaction, tore preferred
is to filter anc! wash the particles after the
synthesis to remove any free salt or acid of the first
Core dopant type or depending on the degree of washing
to remove a surface layer of the core dopant from each
particle. A dopant layer of different composition car.
be then achieved by washing or slurrying the polymer
particles in a solution of the new dopant. Repeatedly
washing with different dopants will produce multiple
layers. It is preferred that primary particles rather
than aggregates receive a core/shell dopant
structure. It is preferred that the aqueous or
nonaqueous solvent or solvent miature employed in the
procedure act to swell the polyaniline particles. It
is also preferred that the entire procedure act to
swell the polymer particles. It is also preferred
_ 39 _.
that the entire precedure from synthesis through to
the formtion of a layered dopant structure be carried
out while keeping the polyaniline particles wetted by
a liquid which swells the polyaniline.
The electrically conductive polyaniline
composition of this invention can be used for any
purpose for which conductive polymers are useful. For
example, the composition can be used to form
electrically conductive articles for shielding
purposes, anti-static purposes or adhesive. Eaamples
of articles include conductive polymer housings for
EMI Shielding of sensitive electronic equipment such
as microprocessors, infrared, radio frequency and
microwave absorbing shields, flexible electrically
conducting connectors, conductive bearings, brushes
and semiconducting photoconductor junctions,
electrodes, capacitors, optically transparent or
non-transparent corrosion-preventing coatings for
corrodible materials such as steel, antistatic
materials and optically transparent or non-transgarent
coatings for packaging electronic components,
antistatic carpet fibers, wanes for floors in computer
rooms, antistatic finishes for CRT screens, aircraft,
auto windows. electostatic dissipative packaging for
electranics, and the like.
The particles of this invention are particularly
suited for uae in the manufacture of emulsions,
suspensions of the polyaniline, blends of the
polyaniline with other polymers as for ezample, other
conjugated backbone polymers, thermoplastic polymers
such as polyamides, polycarbonates, polyesters,
polylactones, polyolefins, polyacrylics; thermosetting
resins such as phenolics and phenolic derivatives,
alkyds. unsaturated polyester, epozies, melamines,
amino resins and allylics; and miztures thereof. For
eaample, blends of conductive polyaniline particles
which are inherently highly polar may be made with a
~~~9~~~
- 40 -
polymer such as polyethylene terephthalate glycol)
(PETG) or polycarbonate (PC) by combining a core
dopant such as tosylate (CH3(C6H4)S03-), which offers
hiah conductivity with a surface dopant such as
dodecylbenzene sulfonate which offers increased
compatibility with PETG or PC via the long-chain alkyl
substituent tin the dopant anion.
The following specific examples are presented to
more particularly illustrate the invention, and should
not be construed as being limitations or. the scope and
spirit of the inveNtion.
Polyaniline (PAni) (320G) doped with pare-toluene
sulfonic acid (PTSA) (PAni-OTs) (approa. 8~ S) was
filtered on a Huchner funnel and was placed into a
bucket, and 3 liters of 1 M PTSA having a
concentration of 1 mol/L were added and stirred for
1/2 hour. The material was again filtered on the
Buchner funnel. Then the filtrate was combined with 3
liters of boiling water and the mixture was stirred
with an agitator/miaer for 10 minutes, then filtered
on the Huchner funnel. The filter cake had a sulfur
content of about ~ ~ by weight. A solution of
methanol (2.SL) containing 2 weight ~ of
pare-dodecylbenxene sulfonic acid (DeSA) were added to
the filter cake and stirred for 1/2 h. The mizture
was then filtered again. The filtered material was
dried in a fluid bed dryer at a maximum temperature of
80 °C.
The skin/core particles, (PAni-tosylate
(OTs)-dodecylbenzene sulfonate (D8S)), and polyaniline
tosylate (PAni-OTs) particles were combined with
matrix polymers, polycaprolactone (PCL) and (PETG),
into composites.
- ql -
The relative proportions of the polyaniline
components were varied ow er a range of samples from
about 50% by weight polyaniline to about 5% by
weight. Conductivity of compression molded samples of
each blend were measured by a four-probe technique. A
plot of the logarithim of conductivity as a function
of volume percent polyaniline gave an approximately
"S" shaped curve in each case. Such characteristic
"percolation" curves were analyzed to determine a
"Percolation point" (the point of steepest rise in
conductivity) specified by the volume percent loading
of polyaniline at that point, and the saturation
conductivity as evidenced by the conductivity observed
for the highest loading level for polyaniline in the
blend.
The results are set forth in the following Table
II. In the Table, the conductivity of polyaniline is
given in the first row and is that taken on a
compressed pellet consisting of 100% polyaniline
containing the specified dopant anion(s). The
saturation conductivity given in the bottom row refers
to the blend with PETG.
Doped PAni Particles
(PAni-OTs) (PAni-OTs/DBS)
A~ Conductivity of PAni 7.55 S/em 4.5 S/cm
H. Percolation Point in PCL 8°~ 8°~s
C. Percolation Point in PETG 20-25% 9.5%
D. Saturation Conductivity
in PETG 5 z 10-'~ S/cm 2.5 S/cm
~~~9~'9~.
EXAMPLE Z
Polyaniline tosylate (PAni-OTs) was prepared from
aniline, p-toluene sulfonic acid (PTSA), and ammonium
persulfate solution by first combining the aniline and
the acid, and then slowly adding the ammonium
persulfate solution to the acid and aniline solution
in approximately one hour. The solids which were
formed were then filtered and washed successively
twice with water (75°C), once with 5% solution of PTSA
(slurry for 1 to 2 hrs), and finally with a z%
solution of PTSA in methanol. After filtration, the
solids were dried in a vacuum oven at 130°C until the
temperature of the powdered solids reached 110°C. The
water content of the solids was determined to be less
than 3% by weight.
E~IF'~~
Polyanilinium tosylate coated by dodecylbenzene
sulfonate (PAni OTs/DBS) was prepared as in Examgle 2
with the exception that dodecylbenzene sulfonic acid
(DHSA) was substituted for the PTSA in the final
methanol wash. By elemental analysis the resulting
dried powder was found to contain approximately (by
molar ratio) 70~ DTs and 30% DBS. Since exposure of
PAni OTs to a concentrated solution of DBSA will cause
the replacement of PTSA with DHSA via a process which
requires the outward diffusion of PTSA and the inward
diffusion of DBSA, the above process produced a
polyaniline which was preferentially doped on the
surface of each powder grain and/or primary particle
with DHSA.
EXAMPLE 9
Polyaniline tosylate coated by naphthalene
disulfonate was prepared by the procedure of Example 3
wherein naphthalene disulfonic acid (NDSA) was
substituted far PTSA only in the final methanol wash
and this wash was maintained at 75°C.
- 93 -
Polyaniline tosylate heavily exchanged with
dodecylbenzene sulfonate (PAni-OTslDBS (heavy) and
polyaniline tasylate heavily exchanged with
naphthalene disulfonate (PAni-OTs/NDS (heavy)) where
prepared in the manner of Example 2, with the
exception that DBSA and NDSA were substituted far PTSA
in the final two washes, the first was being made at
75°C.
to
EXAMPLE 6
The relative thermal stabilities of the various
forms of polyaniline, described in Examples 2-5 above,
were determined by the following procedure: The
Powdered polyaniline was compressed into pellets with
a diameter of 0.7 cm and a thickness of about 0.09
cm. The pellets were placed in an apparatus in which
the given pellet was contacted by gold pins at four
equally spaced points (90 degrees apart) near the
circumference of the pellet. In this configuration a
four-probe resistance measurement could be made which
could be used to calculate the bulk conductivity of
the pellet from the equation aØ215/(Rd), where ~ is
conductivity in S/cm (or ohm'lcm-1), R is resistance
in ohms, and d is pellet thickness in cm. The pellet
was maintained in an atmosphere of flowing nitrogen
and was held at various constant temperatures (130°C,
150°C, 170°C, 200°C, and 230°C) while the
conductivity
was observed to decay. In order to insure that all
samples were thoroughly dry, the pellets were first
held at 150°C for 16 hours before conductivity data
were taken. All of the samples exhibited a decay in
conductivity as an exponential function of time at a
given temperature which could be described by the
relation,
o(t) - a°e-(t/z)a
where Q(t) is the conductivity at a time, t; BO is
the initial conductivity at time t . 0: 2 is an
2~?~1
- 49 _
experimentally determined characteristic decay time;
and a is an experimentally determined parameter for a
given sample at each temperature. The value of a
typically lay in a range from 0.77 to 1Ø With the
help of this equation a charateristic half-life of the
conductivity can be determined at each temperature
from the value of ~ and a determined at that
temperature according to the relation,
tl/2 ' (ln2)1/a
where In is the naperian logarithm and tl/2 is the
time required for the conductivity to decrease by half
(half life). Since the determination of T and a can
be made from the functional form of the decay at early
times, this method does not require that the
conductivity be driven down to one half its original
value at each temperature. As a result, this method
allows the determination of the half lives at the five
temperatures listed above on the same sample without
unduly altering the thermal decay characteristics of
the sample by heavily degrading the sample at each
temperature. The following Table II summarizes the
results obtained for the various polyaniline samples.
In the Table II, the abbreviations have the
following meanings:
(a) "PAni-OTS" is polyaniline doped with tosylate
as in Ezample 2.
(b) "PAni-OTS/DHS" is skin/core polyaniline
particles doped with tosylate at the core and doped
with dodecylbenzene sulfonate at the skin as in
Example 3.
(c) "PAni-OTs/DHS (heavy)" is polyaniline
heavily doped with dodecylbenzene sulfonate as in
Example 5.
3~ (d) "PAni-OTS/NDS" is skin/core polyaniline
particles doped with tosylate at the core and doped
with naphthalene disulfonate at the skin as in Example
4.
- 45 -
(e) "PAni-OTs/NDS (heavy)" is polyaniline heavily
doped with naphthalene disulfonic acid as in Example S.
able II
Conductivity Half Lives of Polyaniline Compositions
Composition CTO tl/2(170°C) tl/2(200°C) tl/2(230°C)
(S/cm) (h) (h) (h)
PAni-OTs 5.4 20.6 1.8 0.15
PAni-OTs/DBS 6.2 20.0 1.5 0.21
PAni-OTs/DBS
(heavy) 0.9 10.1 1.3 0.23
PAni-OTs/NDS 6.4 54.3 4.1 0.34
PAni-OTs/NDS 1.0 98.6 15.8 1.4
(heavy)
The conductivity given in the Table II, a . is that
obtained at 150°C after drying 16 hours at 150°C. The
conductivity half lives, tl/2, are those measured at
170°C, 200°C, and 230°C. The data are arranged in
order of thermal stability at the highest temperature
230°C. The data fox the samples having a skin/core
arrangement of different organic sulfonate dopant
anions illustrate a synergy of desirable properties
which goes beyond a simple average. The core and skin
cosabination of PTSA and DBSA, respectively, (PAni
OTa/DHS) results in a conductive polyaniline which
combines the higher thermal stability of PAni/DHS with
the high conductivity of PAni/OTs. hikewise, the PAni
OTs/NDS sample combines the high conductivity of
PAni/OTs with a significant improvement in the thermal
stability stemming from its skin of the dopant, NDSA,
even though this sample received only a light
treatment with NDSA in the final wash. The sample
PAni OTs/NDS (heavy) shows an even more substantial
increase in thermal stability. Fox comparison with
2~69?~1
- 46 -
the results of Table II, a sample of polyaniline doped
with hydrochloric acid was also tested. This sample
was treated at temperatures below 100°C because it was
to resistive to measure at temperatures above 100°C.
The initial conductivity offer drying at 90°C was 2.9
S/ctn.
Example 7
The data for the half lives taken as in Example 6
at 130°C, 150°C, 170°C, 200°C, 230°C was
shown to
follow an Arrhenius exponential as a function of
temperature of the form,
tl/2 ' t(1/2)°eEa/KT
where a is the base of the naperian logarithm and K is
the Boltzmann constant. The activation energy, Ea,
was determined from the slope of a plot of ln(tl/2] vs
the inverse of absolute temperature in degrees
Kelvin. The naperian logarithm of the prefactor,
In((tl/2)0]~ was determined from the intercept at
1!T'0. These empirically determined parameters were
then used to predict the thermal stability (i.e., the
conductivity half life) over a range of temperature
eatending from 50°C to about 280°C. The agreement
between the predicted variation of half-life and data
taken for PAni-OTs is shown in Figure 1 projected
results are given in Figure 2 for PAni OTs,
PAni-OTs/DBS and PAni-OTs/DBS (heavy). Figure 3
compares the projected results obtained for PAni-OTs,
PAni-OTs/NDS and PAni-OTs/NDS (heavy). These figures
illustrate that the thermal stability for the samples
with a skin/core dopant arrangement is enhanced beyond
a simple averaging of properties. These data were
used to estimate an upper limit for processing
termperature (Tp) and for continuous use temperature
(Tu)~ Temperatures corresponding to maaimum
processing times of 0.1 h and l.Oh Were calculated
along with the temperatures where the continuous use
2(~~~?~~.
time was 5 years. 'table III below summarizes the
results obtained for the various compositions which
were tested.
TABLB III
Use Temperature and Processing Temperatures
of Polyaniline Compositions
Composition Tu Tp(lh) Tp (O.lh)
(C) (C) (C)
PAni-OTs 97 206 239
PAni-OTs/DBS 84 207 245
PAni-OTs/DBS (heavy) 68 203 246
PAni-OTs/NDS 112 217 249
PAni-OTs/NDS (heavy) 112 239 280
Table III indicates that the addition of DHSA or
NDSA as a surface dopant on PAni-OTs raises the
processing temperature in each case. As shown in
Table Iv, the use temperature of PAni-OTs/DBS is found
to be intermediate between that of PAni-OTs and
PAni-OTs/DBS (heavy), and these is a small increase in
the higher processing temperative for both (DHSA
treated) samples in comparison With PAni-OTs. The use
temperatures of PAni-OTs/NDS and PAni-OTs/NDS (heavy)
are found to be nearly equivalent, yet the processing
temperatures for the sample with a heavy skin of P1DS
anions are much higher than these for the sample with
lightly doped skin layer.
