WO1999016084A1 - Electrically conductive block copolymers containing an intrinsically conductive polymer - Google Patents

Abstract

An electrically conductive block copolymer is composed of a non-intrinsically conductive polymer block bonded to at least one intrinsically conductive polymer block through a linkage group. The intrinsically conductive polymer block is polymerized as the salt of an organic acid. The block copolymer has a high molecular weight, is electrically conductive as synthesized and has a solubility in xylene of at least about 1 % wt./wt. Also provided is a method for producing such block copolymer.

Description

ELECTRICALLY CONDUCTIVE BLOCK COPOLYMERS CONTAINING AN INTRINSICALLY CONDUCTIVE POLYMER

Background of the Invention;

(1) Field of the Invention

The invention relates to intrinsically conductive polymers and, more particularly, to block copolymers comprising an intrinsically conductive polymer (ICP) and method for their synthesis.

(2) Description of Related Art Intrinsically conductive polymers ( ICP ' s ) are one type of electrically conducting polymers that combine the processability properties of a polymer with the electrical conductivity of a metal. Such characteristics make ICP's excellent candidates for use in batteries, conductive coatings, paints and conductive fibers.

During the 1980 's much development work was done on the chemical synthesis of ICP's such as polyaniline. Early ICP's had limited electrical conductivity and were often of low molecular weight. Furthermore, it was learned that doping the ICP's with protonic acids ( e. g. , hydrochloric acid) increased the conductivity significantly, but resulted in the insolubility of the doped ICP in almost all solvents. Higher molecular weights are important to impart to ICP's sufficient mechanical strength to form cohesive films and fibers. Improved polymerization conditions have been found which have resulted in ICP ' s having higher molecular weight, but these high molecular weight ICP ' s that have been doped with low molecular weight protonic acids are still largely insoluble and difficult to process. Later, it was found that high molecular weight ICP ' s could be produced in the neutral, non- conductive form and processed into films and fibers and later doped to yield conductive -films and fibers, but it was also found that such doping after formation can weaken the film or fiber and the doping usually was carried out with low molecular weight acids which can diffuse out of the materials in which they are incorporated, leaving the materials non-conductive once again. Doping with protonic acids of larger molecular size produced ICP ' s with higher solubility and acceptable conductivity. However, the method was time-consuming and the doping was limited to the surface portion of the film or fiber.

Moreover, despite the qualified advances discussed above, intrinsically conductive homopolymers and copolymers of monomers such as aniline, thiophene, pyrrole, furan and carbazole remained of limited commercial use because many commercial applications require improved tensile properties and better compatibility of these polymers with other polymers of commercial importance while maintaining the advantageous conductivity, molecular weight and solubility properties. Recently, some investigators have attempted to solve these problems by forming block and graft copolymers which include one or more blocks of an ICP to provide electrical conductivity and bond the ICP with another polymer having, for example, superior tensile properties. For example, Li et al., Synth. Metals , 20, 141- 149, 1987, reported synthesizing a graft copolymer that included polyaniline blocks pendent from a polystyrene backbone. The polyaniline blocks were polymerized from substituent amine groups on the polystyrene by chemical oxidation of aniline in aqueous solutions of hydrochloric acid. The doped form of the graft copolymer had electrical conductivity of approximately 1.0 S/cm, but was insoluble in chloroform and benzene. No block copolymers were reported to have been synthesized in this work.

Later, Li et al., Synth. Metals , 29 , E329-E336, 1989, reported the synthesis of triblock copolymers formed with aniline and amine-terminal polyethylene glycol. Graft copolymers of polyaniline with poly(p- aminostyrene ) and poly(vinylaminehydrochloride) were also prepared. Aniline polymerization to produce the block copolymers was carried out in aqueous solutions containing hydrochloric acid by the slow addition of the aniline to the aminated polymer in the presence of ammonium peroxydisulfate. Protonated polyaniline- poly(ethylene glycol)- polyaniline (abbreviated as ( PANI )₁₃- ( PEG )_{β 4}-(PAΝI) ) block copolymers had electrical conductivities of from 1.7 x 10^"4 S/cm to 0.62 S/cm and were insoluble in chloroform and methanol. Graft copolymers, protonated with HC1, had electrical conductivities of from 3 x 10"⁴ S/cm to 1.1 S/cm, but were also insoluble in chloroform and methanol. By way of comparison, organic acid salts of polyaniline homopolymer were also prepared and reported in this study.

Nevertheless, there was no disclosure of block copolymers containing organic acid salts of polyaniline in this reference.

U.S. Patent No. 5,095,076 to Clement et al . , reported soluble conductive polyanilines comprising two polyaniline blocks which were synthesized from a central organic group characterized as a flexible segment derived from an organic diamine. The flexible diamine was preferably triethylene tetramine and the resulting polyanilines have an average molecular weight ranging from about 8,000 to about 40,000 and electrical conductivities of the material doped with para-toluene sulfonic acid is up to 12 S/cm. It is stated that the products are not copolymers and that some are soluble up to 12 grams/liter in N-methylpyrrolidone (NMP). U.S. Patent No. 5,227,092, to Han, teaches the synthesis of a triblock copolymer- composed of a central block of a first ICP to which are added two terminal blocks of a second ICP. Surface resistance was reported to be from 10* to 10⁸ ohms/square. However, no non-ICP block was used in combination with the ICP blocks of the copolymer.

Oka, Japanese Patent Type (A) No. 6-256509, reported the synthesis of PANl-polyether-PANl triblock copolymers where the polyether block was either amine- terminated poly(ethylene oxide) or amine-terminated poly(tetramethylene oxydozine p-aminobenzoate) . Aniline was polymerized onto the central polymer block by chemical oxidation in aqueous solutions of hydrochloric acid. The PANI blocks of the copolymer were dedoped by contact with ammonium hydroxide to increase the solubility of the copolymer in organic liquids. Films of the neutral block copolymer were cast from ΝMP solutions and re-doped with gaseous HC1 to provide electrical conductivities of approximately 0.1 to 1.0 S/cm. The reference reported that the de-doped block copolymers could be re-doped by_^ contact with organic acids in liquid phase, but did not describe or demonstrate how such re- doping could be carried out.

While work with block and graft copolymers is promising, problems still remain in obtaining materials having high solubility in commonly used solvents and that also have high molecular weight and retain high electrical conductivity.

Thus, it would be desirable to provide an improve_d ICP-containing polymer of high molecular weight which retains the desirable electrical conductivity properties of the intrinsically conductive homopolymers and copolymers, but that provides solubility in commonly used commercial solvents, retains flexibility when formed into films and/or fibers and demonstrates compatibility with other common polymer materials. A method for synthesizing such materials would. also be desirable.

Summary of the Invention:

Briefly, therefore, the present invention is directed to a novel electrically conductive block copolymer comprising at least one polymer block that is an organic acid salt of an intrinsically conductive polymer and a non-intrinsically conductive block, the electrically conductive block copolymer having a solubility in xylene of at least about 1% wt/wt.

The present invention is also directed to a novel method of preparing an electrically conductive block copolymer which comprises combining a monomer of an intrinsically conductive polymer; a chemical oxidant; a non-intrinsically conductive block precursor having at least one monomer unit of a non-intrinsically conductive polymer that is covalently linked to at least one linkage group having an oxidation potential approximately equal to or less than the oxidation potential of the monomer of an intrinsically conductive polymer; water; and an organic solvent in which the organic acid, the non- intrinsically conductive polymer block precursor, the monomer of an intrinsically conductive polymer and the electrically conductive block copolymer are soluble and in which water is soluble in an amount of at least 6% wt/wt; thereby forming an electrically conductive block copolymer . The present invention is further directed to a novel block copolymer made by the method described above. The present invention is also directed to a nove_l method of preparing an electrically conductive block copolymer which comprises applying an oxidizing electrochemical potential to a monomer of an intrinsically conductive polymer in the presence of water, a non-intrinsically conductive block having at least one monomer unit of a non-intrinsically conductive polymer that is covalently linked to at least one linkage group having an oxidation potential approximately equal to or less than the oxidation potential of the monomer of an intrinsically conductive polymer, and an organic solvent in which water is soluble in an amount of at least 6% wt/wt and in which the organic acid, the non-intrinsically conductive polymer, the monomer polymerizable into an intrinsically conductive polymer and the electrically conductive block copolymer are soluble. A block copolymer made by this method is also provided.

Among the several advantages found to be achieved by the present invention, therefore, may be noted the provision of an electrically conductive block copolymer in which are combined desired properties of high molecular weight^', electrical conductivity, solubility in commonly used commercial solvents and improved compatibility with polymers which are the same as, or similar to, the repeating portion of the non-ICP; and the provision of a method for the production of such electrically conductive block copolymer having the advantageous properties described herein.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description, drawings and appended claims. Brief Description of the Drawings:

Figure 1 is a photomicrograph at approximately 400x of the surface of a film cast from a polyaniline- poly(propylene oxide)-polyaniline triblock copolymer illustrating the homogeneity of the copolymer particles comprising the film;

Figure 2 is a nuclear magnetic resonance proton spectrum of N-phenyl-4-lauramidoaniline-polyaniline diblock copolymer in deuterated dimethylsulfoxide solution showing peaks for benzyl and quinone hydrogens between 6.8^" ppm - 7.2 ppm and for- hydrogens on the aliphatic portion of N-phenyl-4-lauramidoaniline at about 1.3 ppm;

Figure 3 is a UV spectrum of N-pheny-1-4- lauramidoaniline-polyaniline diblock copolymer in tetrahydrofuran solution showing an absorbance maximum at about 600 nm - 650 nm; and

Figure 4 is a schematic representation of the general structure of the subject diblock and triblock copolymers.

Description of the Preferred Embodiments:

In accordance with the present invention, it has been discovered that a monomer of an intrinsically conductive polymer ("ICP monomer") can be combined in the presence of water, a chemical oxidant and an organic solvent, with a non-intrinsically conductive polymer ( "non-ICP" ) that is covalently linked to at least one linkage group, to form a block copolymer that, surprisingly, not only is electrically conductive and has a high molecular weight, but also is soluble in xylene in an amount of at least about 1% wt/wt. In fact, the electrical conductivity of the block copolymer of this invention is typically at least about 10^"6 S/cm; the weight average molecular weight is typically at least about 30,000; and the block copolymer composition is soluble in chloroform as well. Moreover, because various different polymers can be used as the non-ICP component, the non-ICP can be selected to match the characteristics of polymers with which the block copolymer is to be blended, thereby increasing the compatibility of such polymer blends.

The subject block copolymers can be either diblock copolymers or triblock copolymers . As shown schematically in Figure 4, diblock copolymers comprise one non-ICP block and one ICP block, while triblock copolymers comprise one non-ICP block and two ICP blocks. The ICP block is formed from the polymerization of ICP monomers with the polymerization initiated at a linkage group. The non-ICP block comprises a non-ICP covalently linked with one linkage group (for a diblock copolymer), or two linkage groups ( for a triblock copolymer ) to form a non-ICP block precursor. The properties of each of these components will be described in detail below. The ICP Block ^■ The ICP that makes up the ICP block is formed by the polymerization of an ICP monomer, or mixture of ICP monomers . Such monomers are those monomers that are capable of polymerization to form an ICP. Any aromatic heterocyclic or aniline monomer that can be polymerized into an ICP can be used. In general, the term ICP, as used herein, is intended to include any polymer having a polycon ugated n electron system and which is electrically conductive in at least one valence state. ICP's are well known and a comprehensive review of ICP technology can be found in Synthetic Metals , vols. 17 - 19, 1987; vols. 28 - 30, 1989; and vols. 40 - 42, 1991, incorporated herein by reference.

ICP's are, in general, dopable with an ionic dopant species to a more highly electrically conductive state. Illustrative of ICP's which can be useful in this invention are intrinsically conductive homopolymers and copolymers of ICP monomers described herein. Examples o_f such intrinsically conductive homopolymers include, for example, polyaniline, polyacetylene, poly-p-phenylene, poly-m-phenylene, polyphenylene sulfide, polypyrrole, polythiophene, polycarbazole, polyfuran and the like. The substituted or unsubstituted aromatic heterocyclic ICP monomers useful in this invention include pyrrole and substituted pyrroles, p-phenylenes, m-phenylenes, phenylene sulfides, thiophene and substituted thiophenes, indoles, azulenes, furans, carbazoles and mixtures thereof. Aromatic heterocyclic compounds for use in the present invention include the 5- membered heterocyclic compounds having the formula:

wherein each of R¹ and R² is independently hydrogen; alkyl (e.g. methyl or ethyl ) ; aryl (e.g. pheny1 ) ; alkaryl (e.g. tolyl); or aralkyl (e.g. benzyl); or R¹ and R² together comprise the atoms necessary to complete a cyclic (e.g. benzo) structure; and X is -0-; -S-; or

K

— N where R³ is hydrogen, alkyl, aryl, alkaryl or aralkyl. These materials, upon polymerization, result in intrinsically conductive polymers having repeating units of the general formula:

wherein: R¹, R² and X have the definitions set forth above.

In general, substituted or unsubstituted anilines for use in this invention are of the formula:

wherein: n is an integer from 0 to 4; m is an integer from 1 to 5, provided, however, that the sum of n and m is equal to 5;

R² and R* are the same or are different and are hydrogen or are R³ substituents; and R³ is the same or different at each occurrence and is selected from alkyl, deuterium, alkenyl, alkoxy, cycloalkyl, cycloalkenyl, alkanoyl, alkythio, aryloxy, alkylthioalkyl, alkylaryl, arylalkyl, a ino, alkylaraino, dialkylamino, aryl, alkylsulfinyl, aryloxyalkyl, alkylsulfinylalkyl, alkoxyalkyl, phosphonate, alkylsulfonyl, arylthio, alkylsulfonylalkyl, borate, phosphate, sulfinate, arylsulfinyl, alkoxycarbonyl, arylsulfonyl, carboxylate, halogen, hydroxy, cyano, phosphinate, sulfonate, nitro, alkylsilane or alkyl substituted with one or more phosphonate, sulfonate, phosphate, borate, carboxylate, phosphinate, halo, nitro, cyano or epoxy moieties; or any two R³ groups together or any R³ group together with any R² or R* group can form an alkylene or alkenylene chain completing a 3, 4, 5, 6 or 7 membered aromatic or alicyclic ring, which ring can optionally include one or more divalent nitrogen, sulfur, sulfinyl, ester, carbonyl, sulfonyl, or oxygen atoms; or R³ is a divalent organic moiety bonded to the same or a different substituted or unsubstituted aniline moiety or R³ is an aliphatic moiety having repeat units of the formula:

wherein q is a positive whole number; provided that said homopolymer and copolymer includes about 10 or more recurring substituted or unsubstituted aniline aromatic moieties in the polymer backbone. The following substituted and unsubstituted anilines are illustrative of those which can be used in the synthesis of the polyaniline block of the block copolymer of the present invention: 2-cyclohexylaniline, aniline, o-toluidine, 4-propanoaniline, 2-

(methylamino)aniline, 2-dimethylaminoaniline, 2-methyl-4- methoxycarbonylaniline, 4-carboxyaniline, N-methyl aniline, N-propyl aniline, N-hexyl aniline, m-toluidine, o-ethylaniline, m-ethylaniline, o-ethoxyaniline, m- butylaniline, m-hexylaniline, m-octylaniline, 4- bromoaniline, 2-bromoaniline, 3-bromoaniline, 3- acetamidoaniline, 4-acetamidoaniline, 5-chloro-2-methoxy- aniline, 5-chloro-2-ethoxy-aniline, N hexyl-m-toluidine, 2-acetylaniline, 2,5 dimethylaniline, 2,3 dimethylaniline, N,N dimethylaniline, 4-benzylaniline, 4- aminoaniline, 2-methylthiom thy1aniline, 4-(2,4- dimethylphenyl ) aniline, 2-ethylthioaniline, N-methyl- 2,4-dimethylaniline, N-propyl m- toluidine, N-methyl o- cyanoaniline, 2,5 dibutylaniline, 2,5 dim thoxyaniline, tetrahydronaphthylaniline, o-cyanoaniline, 2- thiomethylaniline, 2, 5-dichloroaniline, 3-(n- butanesulfonic acid) aniline, 3-propoxymethylaniline, 2, 4-dimethoxyaniline, 4-mercaptoaniline, 4- ethylthioaniline, 3-phenoxyaniline, 4-phenoxyaniline, 4- phenylthioaniline, 3-amino-9-methylcarbazole, 4-amino carbazole, N-octyl-m-toluidine, 4-trimethylsilylaniline, 3-aminocarbazole, N-( paraaminophenyl ) aniline.

The preferred ICP monomer is unsubstituted aniline. The Non-ICP Block As shown in Figure 4, the non-ICP block is derived from a non-ICP block precursor, which is simply the compound that, upon reaction with the ICP monomer, forms the non-ICP block that is bonded to the ICP block. The non-ICP block precursor comprises a non-ICP and one or two linkage groups. The term "non-ICP" means any polymer other than an ICP to which a linkage group can be covalently bonded. Either thermoset or thermoplastic polymers can be used as the non-ICP. The non-ICP can be either water-soluble or water-insoluble. As used herein, a water-insoluble non-ICP is a non-ICP that has a water solubility of less than about 1% wt/wt and a water- soluble non-ICP is a non-ICP that has a water solubility of greater than about 1% wt/wt.

It is preferred that the non-ICP of the non-ICP block has an average degree of polymerization of at least about 2, more preferably at least about 10, and most preferably at least about 20 and up to about 50 or greater, in order to provide to the block copolymer a sufficient level of the characteristics of the non-ICP. For the non-ICP 's useful in this invention, such degree of polymerization corresponds to non-ICP' s having weight average molecular weights of preferably at least about 100, more preferably at least about 500, and most preferably at least about 1,000 and up to about 2,500 or greater. In general, thermoset polymers suitable for use in the non-ICP block of this invention can 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 diallyl phthalate, diallyl isophthalate, diallyl maleate, and diallyl 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 poly 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 diisocynate, 2,4-tolylene diisocynate, 4,4' -diphenylmethane diisocyanate, 1, 6-hexamethylene diisocyanate, 4, 4 ' -dicyclohexylmethane diisocyanate with a polyol such as polyether polyol (trimethylol propane, 1,2,6-hexanetriol, 2-methyl glucoside, pentaerythritol, poly(l,4-tetramethylene ether) glycol, sorbitol and sucrose) , polyester polyols such as those prepared by direct 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 general, thermoplastic polymers for use in the composition of this invention can vary widely. Illustrative of such polymers are polyesters such as polyglycolic acid, polyethylene succinate, polyethylene adipate, polytetramethylene adipate, polyethylene azelate, polyethylene sebecate, polydecamethylene adipate, polydecamethylene sebacate, poly-α,α- dimethylpropiolactone, polypivaloyl lactone, polyparahydro ybenzoate, polyethylene oxybenzoate, polyethylene isophthalate, polyethylene terephthalate, polydecamethylene terephthalate, polyhexamethylene terephthalate, poly-1, 4-cyclohexane dimethylene terephthalate, polyethylene-1, 5-naphthalate, polyethylene-2, 6-naphthalate, poly-1, 4-cycloheχylidene dimethyleneterephthalate and the like; polyamides such as poly-4-aminobutyric acid, poly-6-aminohexanoic acid, poly-7-aminoheptanioc acid, poly-8-aminooctanoic acid, poly-9-aminonanonoic acid, poly-10-aminodecanoic acid, poly-11-aminoundecanoic acid, poly-12-aminododecanoic acid, polyhexamethyleneadipamide, polyheptamethylene pimelamide, polyoctamethylene suberamide, polyhexamethylene sebacamide, polynanomethylene azelamide, polydecamethylene azelamide, polydecamethylene sebacamide, poly-bis-4-aminocyclohexyl-methane-l, 10- decanedicarboxamide, poly-m-xylene-adipamide, poly-p- xylene-sebacamide, poly-2, 2, 2-trimethylhexamethylene terephthalamide, polypiperazine sebacamide, polymetaphenylene isophthalamide, poly-p-phenylene terephthalamide, and the like; polycarbonates such as polymethane bis-4-phenyl carbonate, poly-1, 1-ethane bis- 4-phenyl carbonate, poly-2, 2-propane bis-4-phenyl carbonate, poly-2,2-propane bis-4-phenylcarbonate, poly- 1,1-butane bis-4-phenyl carbonate, poly-1, 1,2-methyl propane bis-4-phenyl carbonate, poly-2, 2-butane bis-4- phenylcarbonate, poly-2,2-pentane bis-4-phenylcarbonate, poly-4, 4-heptane bis-4-phenylcarbonate, poly-1,1-1- phenylethane bis-4-phenylcarbonate, polydiphenylmethane bis-4-phenylcarbonate, poly-1, 1-cyclopentane bis-4- phenylcarbonate, poly-l,l-cyclohexane bis-4- phenylcarbonate, polythio bis-4-phenylcarbonate, poly- 2,2-propane bis-4-2-methylphenylcarbonate, poly-2,2- propane bis-4-2-chlorophenylcarbonate, poly-2,2-propane bis-4-2,6-dichlorophenylcarbonate, poly-2, 2-propane bis- 4-2,6-dibromophenylcarbonate, poly-1, 1-cyclohexane bis-4- 2, 6-dichlor phenylcarbonate, and -the like; polymers derived from the polymerization of α, β-unsaturated monomers such as polyethylene, acrylonitrile/butadiene/styrene terpolymer, polypropylene, poly-1-butene, poly-3-methyl-1-butene, poly-1-pentene, poly-4-methyl-l-pentene, poly-1-hexene, poly-5-methyl-l-hexene, poly-1-octadecene, polyisobutylene, polyisoprene, 1,2-poly-1,3- butadiene( iso) , 1, 2-poly-1, 3-butadiene( syndio ) , polystyrene, poly-α-methylstyrene, poly-2-methylstyrene, poly-4-methylstyrene, poly-4-methoxystyrene, poly-4- phenylstyrene, poly-3-phenyl-l-propene, poly-2- chlorostyrene, poly-4-chlorostyrene, polyvinyl fluoride, polyvinyl chloride, polyvinyl bromide, polyvinylidene fluoride, polyvinylidene chloride, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylcyclopentane, polyvinylcyclohexane, poly-α- vinylnaphthalene, polyvinyl alcohol, polyvinylmethyl ether, polyvinyl ethyl ether, polyvinyl propyl ether, polyvinyl isopropyl ether, polyvinyl butyl ether, polyvinyl isobutyl ether, polyvinyl sec.-buty ether, polyvinyl tert. -butyl ether, polyvinyl hexyl ether, polyvinyl octyl ether, polyvinyl methyl ketone, polymethyl isopropenyl ketone, polyvinyl formate, polyvinyl acetate, polyvinyl propionate, polyvinyl chloroacetate, polyvinyl trifluoroacetate, polyvinyl benzoate, poly-2-vinylpyridine, polyvinylpyrrolidone, polyvinylcarbazole, polyacrylic acid, polymethyl acrylate, polyethyl acrylate, polypropyl acrylate, polyisopropyl acrylate, polybutyl acrylate, polyisobutyl acrylate, polysec. -butyl acrylate, polytert . -butyl acrylate, polymethacrylic acid, polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, polyisopropyl methacrylate, polybutyl methacrylate, polyisobutyl methacrylate, polysec. -butyl methacrylate, polytert. -butyl methacrylate, poly-2-ethylbutyl methacrylate,^" polyhexyl methacrylate, polyoctyl methacrylate, polydodecyl methacrylate, polyoctadecyl methacrylate, polyphenyl methacrylate, polybenzyl methacrylate, polycyclohexyl methacrylate, polymethyl chloroacrylate, polyacrylonitrile, polymethacrylonitrile, polyacrylamide, poly N-isopropylacrylamide, and the like; polydienes such as poly-l,3-butadiene(cis) , poly-1,3- butadiene( trans) , poly-1, 3-butadiene( mixt. ) , poly-1,3- pentadiene( trans) , poly-2-methyl-1-1, 3-butadiene( cis ) , poly 2-methyl-1, 3-butadiene( trans ) , poly-2-methyl-l, 3- butadiene(mixt. ), poly-2-tert.-butyl-l-l,3- butadiene(cis) , poly-2-chloro-l, 3-butadiene( trans) , poly- 2-chloro-l,3-butadiene(mixt. ) and the like; polyoxides such as polymethylene oxide, polyethylene oxide, polytetramethylene oxide, polyethylene formal, polytetramethylene formal, polyacetaldehyde, polypropylene oxide, polyhexene oxide, polyoctene oxide, polytrans-2-butene oxide, polystyrene oxide, poly-3- methoxypropylene oxide, poly-3-butoxypropylene oxide, poly-3-hexoxypropylene oxide, poly-3-phenoxypropylene oxide, poly-3-chloropropylene oxide, poly-2,2- bischloromethyl-trimethylene-3-oxide, poly-2, 6-dimethyl- 1,4-phenylene oxide, PPO, poly-2, 6-diphenyl-l,4-phenylene oxide, and the like, polysulphides such as polypropylene sulphide, polyphenylene sulphide and the like; polysulfones such as poly-4,4' -isopropylidene diphenoxydi-4-phenylene sulphone; noryl, and the like, and/or mixtures thereof.

The non-ICP can also be a naturally-occuring polymer such as, for example, protein, peptide, poly amino acid, nucleic acid, cellulose, hemi-cellulose, starch, poly(lactic acid), poly(hydroxybutyrate), or the like.

It is preferred that the non-ICP be selected from poly(ethylene oxide), poly(propylene oxide), poly (ethylene glycol),- or poly(acylonitrile-co-butadiene) .

The most preferred non-ICP 's are poly(ethylene oxide) and poly( propylene oxide) .

In addition to the non-ICP, the non-ICP block includes one or two linkage groups that are covalently linked to the non-ICP. In its neutral, protonated, form (that is, its form prior to reaction with an ICP monomer) the combination of the non-ICP and attached linkage groups is termed the non-ICP block "precursor". While the non-ICP block precursor can be purchased and used without modification, the precursor can be synthesized, if desired, from a non-ICP and at least one linkage group precursor. When it is said that something is a "linkage group precursor" or that the linkage group is "derived from" a particular compound, it is meant simply that the linkage group is .the residue of that compound after covalently bonding with the non-ICP. Thus, if it is said that the linkage group is derived from, for example, para-aminodiphenylamine, or that the linkage group precursor is,- for example, para-aminodiphenylamine, what is meant is simply that para-aminodiphenylamine is covalently bonded to the non-ICP to form a linkage group. In other words, if the non-ICP has a terminal carboxylic acid group and is represented schematically as

O

II — NON-iςp— c —OH s and the linkage group precursor is para- aminodipheny1amine; i.e.,

H the non-ICP block precursor formed would be

0

wherein the linkage group is

Suitable linkage groups and their precursors are described in general in, for example, Electrochemical Reactions in Nonaqueous Systems , by Mann, C.K., and K.K. Barnes, Marcel Dekker, Inc., 1970, incorporated herein by reference. The linkage group of the present invention forms a covalent bond with the non-ICP and is oxidizable by a chemical oxidant or an electrochemical potential to form a covalent bond with the ICP monomer to initiate polymerization of the ICP monomer into the ICP block. However, the method that is used to link the linkage group to the non-ICP is not critical. Such linkage groups can be chemically linked to a thermoset or thermoplastic polymer described above by any technique as would be readily known to those of ordinary skill and examples of such methods are described by Li et al., Synth. Met., 29:E329-E336, 1989, incorporated herein by reference. For example, when the linkage group is derived from an amine, such amine group could be added by nucleophilic addition such as, for example, the addition of p-aminodiphenylamine to a polymer having a terminal isocyanate group; or to a polymer with a terminal carboxylic acid group, as shown above. Alternately, the terminal amine groups could be added by nucleophilic substitution to a non-ICP by, for example, the combination of p-aminodiphenylamine with a polymer having an epoxy end group.

As shown in Figure 4, the non-ICP block precursor can be bonded to one or two linkage groups. If the non- ICP is bonded to only one linkage group, the non-ICP preferably has at least one non-ICP monomer unit and polymerization of the ICP monomer can be initiated at the linkage group to form a diblock copolymer. However, if the non-ICP is bonded to two linkage groups, then the ICP monomer can commence polymerization on each of these linkage groups to form a copolymer having three blocks as the triblock polymer is shown in Fig. 4.

Preferably the linkage group has an oxidation potential that is approximately equal to or less than the oxidation potential of the ICP monomer. In fact, it is most preferred that the oxidation potential of the linkage group be lower than that of the ICP monomer to maximize the amount of block copolymer formed. When the oxidation potential of the linkage group is lower than the oxidation potential of the ICP monomer, the ICP monomer generally commences polymerization at the linkage group on the non-ICP block rather than forming a homopolymer containing only the ICP monomer. However, the oxidation potential of the linkage group can be equal to, or even somewhat higher than that of the ICP monomer and the formation of the copolymer will still take place. For example, the oxidation potential of the linkage group may be about 10% to 15% higher than that of the ICP monomer and appreciable copolymer will still be formed. As used herein, when the oxidation potential of the linkage group is described as being approximately equal to or less than the oxidation potential of the ICP monomer, it is meant that the oxidation potential of the linkage group compared to that of the ICP monomer is such that formation of the copolymer takes place. Thus, the linkage group ' s oxidation potential can range from lower than the oxidation potential of the ICP monomer to about 10% - 15% above such value, to even greater than 15% above such value so long as formation of the copolymer takes place. Preferably, the oxidation potential of the linkage group of the present invention is also lower than that of any organic solvent that is present when the polymerization is carried out.

It is desirable for the linkage group to be bonded to the non-ICP at or near an end of the non-ICP; that is, the linkage group should be a terminal group. Thus, if the non-ICP block precursor has one linkage group, such linkage group is preferably at or near either end or terminal of the non-ICP. On the other hand, if the non- ICP block precursor has two linkage groups, one of the linkage groups is preferably at or near each of the terminals of the non-ICP. The linkage group is also capable of being incorporated into the polymer chain of the block copolymer.

Linkage groups that are useful in the present invention can be derived from precursors such as carbonyl compounds, quinones, halogenated compounds, phenols, alkoxides, ethers, amines, amides, ammonium salts, heterocyclic aromatic compounds such as thiophenes, pyrroles, furans, azulenes, carbazoles, purines, and the like; viologens such as N-methyl-viologen; acetylenes, thiols, or phosphate containing compounds such as phosphates, phosphines and the like by covalently bonding such precursors to the non-ICP. Preferred linkage groups are derived by covalently linking such compounds as anilines, thiophenes, pyrroles and amine groups to the non-ICP. Preferred amine groups are p- aminodiphenylamine, N,N^*-diphenylhydrazine, benzidine, p- phenoxyaniline, p-phenylaminediamine, p-phenylenediamine, hydroquinone , N,N^*-diphenylamine and higher oligomers of aniline and its derivatives. The most preferred amine group is p-aminodiphenylamine and the preferred linkage group is that derived from p-aminodiphenylamine. Preparation of Block Copolymer

The method of preparing the block copolymers of this invention comprises polymerizing at least one ICP block from ICP monomers with the polymerization initiated at a linkage group of a non-ICP block. The polymerization can be driven by a chemical oxidant or by an electrochemical potential. If the chemical oxidant is water-soluble, the reaction is carried out in the presence of water, an organic acid and a suitable organic solvent.

Organic acids suitable for use in this invention are those which are capable of doping the ICP as it forms during polymerization to form an ICP salt. Thus, the ICP block of the present invention is synthesized as the salt of an organic acid and needs no doping after synthesis to form such salt. Organic acids suitable for use can be water-soluble or water-insoluble. Herein, organic acids having a solubility in water of at least about 10% wt/wt are referred to as water-soluble and those having a solubility in water of less than about 1% wt/wt are deemed water-insoluble. The organic acids suitable for use in the method of the present invention include organic sulfonic acids, organic phosphorous-containing acids, carboxylic acids, or mixtures thereof. Preferred organic sulfonic acids are dodecylbenzene sulfonic acid, dinonylnaphthalene sulfonic acid, dinonylnaphthalenedisulfonic acid, p-toluene sulfonic acid, or mixtures thereof. The preferred organic acid is dinonylnaphthalenesulfoniσ acid. When the preferred ICP monomer, aniline, is polymerized in the presence of one of the organic acids disclosed above, an organic acid salt of polyaniline is formed. Preferred ICP salts of the invention include the para-toluene sulfonic acid salt of polyaniline, the dodecylbenzene sulfonic acid salt of polyaniline and the dinonylnaphthalene sulfonic acid salt of polyaniline.

It is preferred that the polymerization be performed in the presence of a suitable organic solvent. Organic solvents that are useful herein are those in which water is soluble in an amount of at least about 6% wt/wt. The ICP monomer is preferably soluble in the organic solvent in an amount of at least about 5% wt/wt. The organic acid is preferably soluble in the organic solvent in an amount of at least about 10% wt/wt and preferably in an amount of at least about 25% wt/wt or higher. The non-ICP block precursor is preferably soluble in the organic solvent in an amount of at least about 1% wt/wt and preferably in an amount of at least about 5% wt/wt. The block copolymer is preferably soluble in the organic solvent in an amount of at least about 1% wt/wt relative to the weight of the organic solvent, more preferably at least about 5% wt/wt, and most preferably, at least about 10% wt/wt. When the organic solvent is added to a reaction mixture, it is preferred that the organic solvent be capable of forming a mixture with the ICP monomer, the non-ICP block precursor, the organic acid and water, when those components are admixed in suitable amounts at the start of the polymerization. It will be understood that such mixture can be an emulsion, a colloidal solution, a suspension, a dispersion, or a true solution.

Organic solvents that can be used include, for example, alcohols, glycols and ethers that meet the above criteria. Preferred organic solvents include, 2- butoxyethanol, propylene glycol, butyl ether, 1-butanol, 1-hexanol, diethyl ether and mixtures thereof and the most preferred organic solvent is 2-butoxyethanol.

Without wishing to be limited to any particular theory, the inventors believe that the use of such an organic solvent facilitates the formation of high molecular weight ICP blocks of water-insoluble organic acids by maintaining reaction components in solution to an extent which is sufficient to prevent or reduce the premature precipitation of the polyaniline salt in short and low molecular weight chains. It is believed that this emulsion polymerization method produces an ICP salt having higher solubility and higher molecular weight than systems which oxidize ICP monomers in aqueous solution in the presence of organic acids having surfactant properties and organic liquids, such as xylene, in which water is not soluble.

As noted, the block copolymer can be prepared by oxidative polymerization using a chemical oxidant. Chemical oxidants are well known in the art. (For example, see Cao et al., Polymer . 30 : 2305-2311, 1989;

Genies et al., Synthetic Metals , 36 : 139 - 182, 1990; and U.S. Pat. No. 5,567,356). The chemical oxidant can be either water-soluble or organic-soluble. As used herein, the term "water-soluble" with respect to a chemical oxidant means that the oxidant is soluble in water in an amount of at least about 5% wt/wt. Likewise, as used herein, the phrase "organic-soluble" with respect to a chemical oxidant means that the oxidant is soluble in an organic solvent, such as toluene, in an amount of at least about 5% wt/wt.

Water-soluble chemical oxidants can be any of a number of oxidizing agents including chemicals such as ammonium peroxydisulfate, potassium dichromate, potassium iodate, ferric chloride, potassium permanganate, potassium bromate or potassium chlorate. The preferred water-soluble chemical oxidant is ammonium peroxydisulfate. Those of ordinary skill in the art, however, will readily recognize many water-soluble chemical oxidants that would be suitable.

The use of organic-soluble chemical oxidants for the polymerization of aniline is described in general by Cooper et al., Polymer Preprints, 38 ( 1 ) : 117-118, 1997. Organic-soluble chemical oxidants useful in the present invention include such chemicals as 2, 3-dichloro-5, 6- dicyano-p-benzoquinone, 2,3-dichloro-5, 6-dicyano-l, 4- benzoquinone, 2,3,5, 6-tetra-cyano-benzoquinone, tetrachloro-l,4-benzoquinone, 7,7,8,8- tetracyanoquinodimethane, p-benzoquinone, or o- benzoquinone. Preferred as an organic-soluble chemical oxidant is 2, 3-dichloro-5, 6-dicyano-p-benzoquinone. Alternately, polymerization of the ICP monomer can be accomplished by electrochemical oxidation initiated by applying an electrochemical potential to the reaction mixture. Such electrochemical oxidative polymerization techniques are well known in the art and are generally described, for example, in J. Chem . Soc . , Faraday Trans. I, 82: 2385-2400, 1986; J. Electrochem. Soc , 130 ( 7 ) : 1508-1509, 1983; Electrochem. Acta, 27 ( 1 ) : 61-65, 1982; and J. Chem. Soc. Chem. Commun. , 1199, 1984.

The method of making the electrically conductive block copolymer comprises a procedure having the following steps: The reaction mixture is prepared by admixing in any suitable manner the ICP monomer, the non- ICP block precursor, water, the organic acid and the organic solvent, into an aqueous mixture in the relative amounts described herein.

The organic solvent is added to the reaction mixture in an amount of about 1.0 to 100 moles of the organic solvent per mole of ICP monomer, more preferably in an amount of about 4 to 80 moles of the organic solvent per mole of ICP monomer, and most preferably in an amount of about 6 to 62 moles of the organic solvent per mole of ICP monomer.

The non-ICP block precursor can be added to the reaction mixture in any amount selected from a wide range, but preferably from about 0.1 x 10"³ to 200 x 10"³ moles of the non-ICP block precursor, based on a weight average molecular weight of the non-ICP, is added per mole of ICP monomer, more preferably, about 0.5 x 10"³ to 150 x 10^"3 moles per mole of ICP monomer, and most preferably about 1 x 10"³ to 100 x 10"³ moles per mole of ICP monomer.

The organic acid is added to the reaction mixture in an amount of about 0.04 - 5.0 moles of organic acid per mole of ICP monomer, or, more preferably, an amount of about 0.1 to 3.0 moles per mole of ICP monomer, or most preferably about 0.2 - 1.8 moles per mole of ICP monomer.

In the embodiment of the invention in which a water-soluble or organic-soluble chemical oxidant is used to drive the polymerization, the amount of such chemical oxidant which is added to the reaction mixture is about 0.05 - 10.0 moles per mole of ICP monomer, or more preferably, about 0.2 - 3.0 moles per mole of ICP monomer, or most preferably, about 0.4 - 1.25 moles per mole of ICP monomer.

Water is present in the reaction mixture in an amount of about 10 - 1000 moles of water per mole of ICP monomer, or more preferably, about 50 - 600 moles per mole of ICP monomer, or most preferably, about 100 - 460 moles per mole of ICP monomer.

While the type of reactor is not critical, it should be of a type in which controlled agitation can be provided to the solution on a continuous basis and in which the reactor contents can be maintained at a controlled temperature. Since the reaction is expected to be exothermic, the reactor should have a jacket or coils suitable for removing heat and maintaining reactor contents at or below ambient temperature; more specifically to maintain a temperature of from about 0^βC to about 20°C. While the material of construction of the reactor and wetted surfaces is not critical, such materials should be reasonably chemically inert to the reactants and should not participate in or affect the desired reaction.

After the reactants described above are placed into solution in the reactor and cooled to the desired temperature, the chemical oxidant can be added, or the electrochemical potential can be imposed. If the chemical oxidant is water-soluble, such as, for example, ammonium persulfate, it is often added slowly in a water solution to the reaction mixture while the reaction mixture is stirred vigorously. If the chemical oxidant is organic-soluble, it may be added slowly in a toluene solution. Alternatively, the oxidant can be first added to the mixture and the ICP monomer can be slowly added with agitation. In either case, such addition continues until the reaction is brought to the desired level of completion. Often a predetermined amount of oxidant is added to the reaction mixture over a predetermined time period, such as, for example, 30 minutes. After the addition of the oxidant is complete, the reaction can be allowed to proceed for a significant time, such as, for example, over 50 hours, while temperature and agitation are maintained. Such techniques are well known in the art and are generally described in, for example, U.S. Pat. No. 5,567,356 (which is incorporated herein by reference) .

At later stages of the polymerization reaction, the reaction mixture cleanly separates into aqueous and organic liquid phases. The conductive block copolymer product, along with the organic acid, among other components, will separate into the organic phase, whereas the aqueous phase will be largely devoid of the conductive block copolymer. If desired, the block copolymer in the organic phase can be easily separated from the aqueous phase by any of a number of conventiona_l phase separation processes, such as, for example, decanting, continuous-flow centrifugation, selective drawing off one phase, or the like. After the organic phase is separated, it can be washed with hot or cold water or any other desired solvent to remove unreacted ICP monomer, byproducts, or other undesirable materials. The conductive block copolymer can either be used directly from the organic solution, extracted into another solvent such as, for example, xylene, or separated from the solution as a solid. If it is desirable to use the conductive block copolymer directly from the organic solution, such solution can be applied as a film or coating and the solvent removed by evaporation. Alternatively, the solution could be mixed into a spinning dope for the formation of wet spun or solution spun fibers.

If it is desirable to isolate the conductive block copolymer from the organic liquid phase, the polymer can be precipitated by adding methanol, or other suitable solvent, to the organic phase. Upon precipitation, the solid conductive block copolymer can be separated from the liquid by decanting, centrifugation, filtration or the like, and any remaining solvent can be removed by drying or evaporation. The solid conductive block polymer can then be used in any manner mentioned above, or can be blended with other polymers, or formed into any useful article, such as films, fibers, coatings and the like by any conventional means used for such purposes.

The copolymer of the present invention is a block copolymer in that it is a polymer comprising molecules in which there is a linear arrangement of blocks, a block being defined as a portion of a polymer molecule in which the monomeric units have at least one constitutional or configurational feature absent from the adjacent portions. In a block copolymer, the distinguishing feature is constitutional, i.e., each of the blocks comprises units derived from a characteristic species of monomer. (Polymer Handbook, 3rd Ed., J. Brandrup and E.H. Immergut, Eds., Wiley Interscience, 1989).

The block copolymer of the present invention comprises at least one block of an organic acid salt of an ICP (the "ICP block") covalently linked to a non-ICP block through a linkage group in the non-ICP block. The molecular weight of the block copolymer is the sum of the molecular weight contributions of the non-ICP block, including any linkage groups, and the one or more ICP blocks. The molecular weight contribution of the ICP blocks can be calculated by subtracting the molecular weight contributions of the non-ICP block, including any linkage groups, from the molecular weight of the block copolymer. If the copolymer contains more than one ICP block, the average molecular weight contribution of each ICP block can be calculated by dividing the molecular weight contributions of the ICP blocks by the number of ICP blocks present in the copolymer. For example, for a triblock copolymer having a molecular weight of 50,000, with a non-ICP block comprising a non-ICP of molecular weight 5,000 and two linkage groups, each of molecular weight 200, the average molecular weight of each ICP block would be 22,300 and could be calculated as: (50,000 - (5,000 + (2(200) )))/2 = 22,300 In the present invention, the ICP block preferably has a number average molecular weight of at least about 2,000, more preferably at least about 5,000 and most preferably at least about 10,000 or higher. While the size of the non-ICP block is fixed by the non-ICP selected for use in the copolymer, the molecular weight, or chain length of the ICP block is determined by the type and amount of reactants and the reaction conditions. For example, a higher ratio of ICP monomer to non-ICP in the reaction mixture would be expected to yield a higher chain length for the ICP segments of the block copolymer. The characteristics of both ICP and non-ICP blocks contribute to the characteristics of the block copolymer. For example, a non-ICP block of poly( ethylene oxide) can increase the water solubility of the block copolymer, while poly(propylene oxide) can increase the solubility of the block copolymer in organic solvents. The growth of the ICP chain of the ICP block,- however, modifies the solubility characteristics of the copolymer and enhances such characteristics as electrical conductivity and insolubility in conventional organic solvents . The compatibility of the block copolymer with other polymers in polymer blends also depends on the relative sizes of the ICP block and non-ICP block. For example, the compatibility of a polyaniline-poly( ethylene oxide )- polyaniline block copolymer with a polymer such as polyethylene in a polymer blend may be reduced as the size of the polyaniline blocks increases.

In general, it is preferable to use a non-ICP of the type and molecular weight sufficient to provide desirable tensile, solubility and compatibility properties to the copolymer and to synthesize one or more ICP blocks having molecular weight sufficient to provide desirable electrical conductivity properties to the copolymer. Thus, the non-ICP block includes at least one monomer unit of a non-ICP and, if the copolymer includes more than one ICP block, the non-ICP block comprises a non-ICP of at least two monomer units and preferably at least four monomer units.

It is an advantage of the present invention that the emulsion polymerization method of polymerizing the ICP of the ICP block results in a copolymer with higher solubility in organic solvents than a copolymer comprising an ICP polymerized by conventional aqueous methods. The electrically conductive block copolymer of the present invention is soluble in xylene in an amount of 1% wt/wt, or greater, preferably in an amount of 2% wt/wt, or greater, more preferably in an amount of 5% wt/wt, or greater, and most preferably in an amount of 10% wt/wt, or greater. This advantage gives increased organic solubility to copolymers having relatively large non-ICP blocks of hydrophylic polymers such as poly( ethylene oxide) and also having relatively high molecular weight ICP blocks. For .example, a polyaniline- poly(ethylene oxide)- polyaniline triblock copolymer polymerized by emulsion polymerization methods previously described herein in the presence of water, 2- butoxyethanol and dinonylnaphthalenesulfonic acid results in a copolymer that is 1% wt/wt soluble in chloroform when the degree of polymerization of the poly( ethylene oxide) is at least about 25, more preferably at least about 50 and most preferably at least about 100 and the molecular weight of each polyaniline salt block is at least about 2,000.

The ability to form a copolymer with a combination of properties is advantageous when it is desired to obtain compatibility with other polymers chemically similar to poly(ethylene oxide) while maintaining useful levels of conductivity and tensile properties.

The copolymers of the present invention may be used for any application where the electrical conductivity properties of an ICP are desirable. The copolymers may be used as components of paints, films, fibers, coatings, molded articles, electrodes, or the like. They may also be advantageously used in corrosion- resistant paints and coatings, or anti-static additives or coatings, or in conductive adhesives. The following examples describe preferred embodiments of the present invention. Other embodiments within the scope of the claims herein will be apparent to one skilled in the art from consideration of the specification or practice of the invention as disclosed herein. It is intended that the specification, together with the examples, be considered exemplary only, with the scope and spirit of the invention being indicated by the claims which follow the examples. In the examples which follow, all percentages are given on a weight basis unless otherwise indicated.

EXAMPLES 1 - - 3 This example illustrates the synthesis of the polyaniline dinonylnaphthalenesulfonic acid salt (PANDA) and poly(ethylene oxide) (PEO) triblock copolymer ( PANDA- PEO-PANDA) in the presence of 2-butoxyethanol.

Dinonylnaphthalene sulfonic acid (DNNSA), (69.0 g; 0.15 mole) and 2-butoxyethanol (69 g; 0.58 mole) were added to a glass jacketed reactor. DNNSA in 2- butoxyethanol is available, for example, as Nacure 1051® (King Industries, Inc., Norwalk, CT). Aniline, (14.85 g; 0.09 mole); poly(ethylene oxide) diamine terminated (M„ = 4,900, degree of polymerization = 100), (2.2 grams, 4.5 x 10^~* moles); and water (300 ml; 16.67 mole) were also added to the reactor. After the contents were cooled to 0^βC, ammonium peroxydisulfate (25.6 g; 0.112 moles), in 25 ml (1.39 mole) water was added dropwise to the reactor over a 30 minute period. After two hours the solution turned from brown to blue-green. The solution was stirred at 2° - 3"C for 51 hours. After the stirring was stopped, a green organic layer separated cleanly to the top of the mixture. The water layer was removed with a syringe and the organic layer was washed twice with 200 ml portions of water. Interestingly, no exotherm was observed after one day as is typically observed in the polymerization of aniline alone. The molecular weight of the block copolymer was determined by gel permeation chromatography (GPC) coupled with a refractive index detector. Two Ultrastyragel columns with mean permeabilities of 10⁵ Angstroms and 10³ Angstroms were used at a flow rate of 0.5 ml/min and at a controlled temperature of 45 ^βC. N-methyl pyrrolidone (NMP) solution containing 0.02 N ammonium formate was used as GPC eluent or solvent. The block copolymers containing polyaniline were treated with ammonium formate as a modifier to maintain the ICP salt in the deprotonated state and to reduce polymer binding to the column. The molecular weight of the copolymer was measured by GPC. The GPC columns were calibrated by twelve polystyrene standards with weight average molecular weights (M„) ranging from l.lxlO⁶ to 3000 g/mole. The copolymer of this example indicated a weight average molecular weight (M„) of 126,500 and a number average molecular weight (M„) of 84,300 and having a polydispersity (M^ ,,) of 1.5. The chromatogram did not show a peak for PEO, indicating the product is not a mixture of polyaniline and PEO. A portion of the polymer was precipitated with methanol and dried in air to yield a dark green powder. The polymer was found to be very soluble in toluene, xylenes, tetrahydrofuran (THF) and chloroform. The absorbance maximum (λ_aax) was found to be 755 nm in THF.

Synthesis was repeated as above, but with 11 g, (22.4 x 10'* moles) of PEO for Example 2 and 0.44 g, (0.9 x 10"⁴ moles) of PEO for Example 3. Absorbance maxima in THF for these two examples were 759 nm and 741 nm, respectively. The weight average and number average molecular weights were similar for the triblock copolymers synthesized with the molar ratio of the non- ICP:aniline ranging from 1 x 10"³ to 25 x 10^"3 (Table 1). TABLE 1

EXAMPLE 4 This example illustrates the electrical conductivity of a film cast from PANDA-PEO-PANDA triblock copolymer.

The triblock copolymer of Example 2 was solubilized in THF and a thin film was cast onto a Mylar® plastic sheet on which two, spaced gold electrodes were deposited. The THF was evaporated and the resistance, width and thickness of the film were measured. The conductivity of the film was calculated to be 8 x 10^"3 S/cm.

EXAMPLE 5

This example illustrates the synthesis of a PANTSA and poly(propylene oxide) (PPO) triblock copolymer (PANTSA-PPO-PANTSA) in the presence of n-butanol.

Poly(propylene oxide) (PPO), (M,, - 4,000, DP » 69) terminated on each end with para-aminodiphenylamine,

(1.25 g, 3 x 10"^Λ moles), and n-butanol (60 ml; 0.66 mole, available from Fisher Scientific) were added to a 150 ml round flask equipped with a magnetic stirring bar. After the mixture became a brown solution, para-toluene sulfonic acid (pTSA), (2.70 g; 0.0157 mole), available from Aldrich Chemicals, was added and the solution became light green. Then 20 ml (1.11 mole) of deionized water was added and the solution placed in an ice bath for 30 min while stirring continued. Next, ammonium peroxidisulfate, (NH_<)₂S₂O_a, (2.16 g; 0.0095 mole), was added and the material became a dark green emulsion. After stirring at 0°C for 5 min, aniline, (1.0 g; 0.0107 mole ) , available from Acros, was added and the emulsion became dark blue. After stirring at 0°C for 40 min, it became a green emulsion again and was stirred at 0°C for an additional^" 14 hrs. After standing at 0^βC for 30 min, the aqueous phase was removed and the solid copolymer was washed with 50 ml of deionized water. After removing the aqueous wash phase, 50 ml of a 1 M solution of pTSA in water was added to the copolymer. The electrical conductivity of a thin film cast from this material, with no further phase separation, was measured as 0.2 S/cm by the method described in Example 4.

The emulsion was washed with 100 ml DI water and the aqueous phase again removed. The electrical conductivity of the film was measured at 1.0 S/cm by the method described in Example 4. After drying in a vacuum oven at 60°C for 40 hrs, the electrical conductivity of the film was measured at 4 S/cm. The molecular weight of this material was: Mw - 55,800 and M„ = 26,300. The polydispersity was 2.1. A photomicrograph of the film taken at about 400x, shown in Figure 1, illustrates the homogeneous size of the copolymer particles composing the film. Only one peak was observed on a gel permeation chromatogram (GPC) of the material, indicating the lack of homopolymer in the copolymer product. EXAMPLE 6 This example illustrates the synthesis of a PANDBSA-PPO-PANDBSA triblock copolymer polymerized in the presence of n-butanol. Poly(propylene oxide), terminated on each end with p-aminodiphenylamine, (M„ = 4,000) (1.25 g); n- butanol (60 ml; 0.66 mole); dodecylbenzenesulfonic acid (DBSA), (4.67 g, 0.0143 mol ) ; and deionized water (20 ml; 1.11 mole) were added to a 150 ml flask. The mixture became a light green emulsion. After stirring at 0°C for 30 min, ammonium peroxidisulfate,- (NH₄ )₂S₂0₈, (3.08 g; 0.0135 mol) was added and the emulsion stirred at 0 - 5°C for 7 min until most of the salt dissolved. Then, aniline (1.0 ml; 0.011 mol) was added by syringe and the emulsion stirred at 0 - 5°C. It became a light blue emulsion after 5 min and a dark green slurry af er 1.0 hr. The slurry was stirred at 0 - 5°C for another 14 hrs and at room temperature for an additional 8 hours. The aqueous phase was removed by pipette and the organic phase washed twice with 50 ml portions of DI water. A green emulsion product was obtained (48 g ) .

The weight average molecular weight, M„ = 41,700 and the number average molecular weight, M„ = 22,600. The polydispersity of the copolymer was 1.8. The polyaniline block of the copolymer could be easily converted to the base form. To a 10 ml test tube were added the green emulsion (2.0 g), methanol (4.0 g) and triisopropylamine (0.20 g) . The slurry became blue (indicating formation of the emeraldine base form of polyaniline), and a blue precipitate was separated by centrifugation.

EXAMPLE 7 This example illustrates the synthesis of a PANDBSA-PPO-PANDBSA triblock copolymer polymerized in the presence of n-butanol as in Example 6, except at different concentrations and ratios of reactants and with different recovery technique.

Deionized water (200 ml, 11.1 moles), DBSA (33.0 g, 0.10 moles), n-butanol (200 ml, 2.185 moles), aniline (5.5 g, 0.059 moles) and poly(propylene oxide), diamine terminated, (Mw = 4,000) (27.5 g, 6.9 x 10"³ moles) were added to a 1 liter jacketed reactor equipped with a cooler, a separatory funnel and a mechanical stirrer. The mixture became a milky emulsion. After cooling to 0^β-5^βC, ammonium peroxidisulfate (17 g, 0.075 moles in 40 ml DI water) ^"was added dropwise over 30 min. The mixture became a green emulsion after 20 min. and was stirred at 0° - 5°C for an additional 17 hrs. The resulting green emulsion was poured into excess methanol ( 700 ml ) and the precipitated product was collected by vacuum filtration and washed with methanol (3 x 100 ml). After drying in air for 3 hrs . a green powder product (8.8 g ) was obtained.

This powder was tested by GPC for molecular weight and was: M„ = 35,500, M_, = 10,400 and M_^/M,, = 3.41. The GPC trace showed one main peak with a shoulder.

EXAMPLE 8 This example illustrates the synthesis of a PANTSA poly(propylene glycol) (PPG) triblock copolymer (PANTSA- PPG-PANTSA) polymerized in the presence of n-butanol.

Poly(propylene glycol), di-ADPA terminated, (M„ = 4,300, M_v/N_, = 1.04), (1.25 g, 2.9 x 10"" moles), n-butanol (30 ml, 0.328 moles), aniline (0.5 g, 0.0053 moles), pTSA (1.34 g, 0.00705 moles) and DI water (40 ml, 2.22 moles) were added to a 100 ml stirred round flask. The mixture was cooled to 5^βC in an ice bath and ammonium peroxidisulfate (1.08 g, 0.00473 moles, in 3 ml water) was added dropwise over 5 min. After 10 min. the mixture changed from a light green emulsion to a blue emulsion and then turned into a brown emulsion. The mixture was stirred at 5^βC for 16 hrs. and at room temperature for an additional 10 hrs. Then more ammonium peroxidisulfate (0.7 g, 0.00307 moles) was added to the emulsion and it was stirred at room temperature for 24 hours. The organic layer that separated to the top of the mixture was collected and washed with DI water (2 x 20 ml ) . The dark green solid was tested for molecular weight and l = 31,400, M„ = 9,700 and was: M_w/M,, = 3.2.

EXAMPLE 9

This example illustrates .the synthesis of a PANTSA-PPG-PANTSA triblock copolymer polymerized in the presence of n-butanol as in Example 8, except at a lower non-ICP: ICP monomer ratio and for a shorter time. Poly(propylene glycol), di-ADPA terminated, (M„ =

4,300), (1.25 g), aniline (1 g, 0.0106 moles), and n- butanol (60 ml, 0.655 moles) were added to a 250 ml round flask equipped with a magnetic stirring bar. When the polymer dissolved, pTSA (2.68 g, 0.00141 moles) and DI water (40 ml, 2.22 moles) were added and a light green emulsion was formed. After cooling in an ice bath for 30 rain, ammonium peroxidisulfate (2.16 g, 0.0095 moles in 3 ml DI water) was added to the emulsion over 30 sec. After 5 min., the mixture became a dark green emulsion, a brown emulsion after 30 min. and a green-brown emulsion after 1 hr. The mixture was then stirred at 0°C for 14 hrs. Then the temperature was raised to room temperature and the mixture was stirred for an additional 6 hrs . The mixture was allowed to stand for 30 min. and the organic layer was collected and washed with DI water (2 x 50 ml). The organic layer was evaporated to give a dark green gel which had a molecular weight by GPC of M„ - 30,700, M_n = 10,200 and M_*/^ = 3.0 with two peaks on the GPC trace. EXAMPLE 10 This example illustrates the synthesis of a PANDA poly(acrylonitrile-co-butadiene) (PAB) triblock copolymer ( PANDA-PAB-PANDA) polymerized in the presence of 2- butoxyethanol .

DNNSA (105 g, 0.223 moles), 2-butoxyethanol (105 g with the DNNSA plus an additional 240 ml, 2.72 moles total), aniline (13.6 g, 0.146 moles), poly(acrylonitrile-co-butadiene), di-amino terminated, (Mw = 3,800), (81 g, 2.1 x 10^-2 moles), and DI water (600 ml, 33.33 moles) were added to a 1 -liter reactor equipped with a mechanical stirrer and a separatory funnel . After cooling to 5°C, ammonium peroxidisulfate (39 g, 0.17 moles, in 90 ml DI water) was added dropwise over 45 min. The emulsion changed from yellowish to brown and, after 2 days, became a green emulsion. After stirring at 0°C for six days, the green organic layer was collected. The organic layer was poured into excess methanol ( 2 liters ) and the viscous copolymer that was formed was washed with methanol (6 x 150 ml), water (2 x 150 ml) and methanol (2 x 150 ml) before drying in a vacuum at 60°C overnight. A dark green solid (11 g) was collected.

The molecular weight of the material was measured by GPC to be M„ = 24,500, M„ = 9,140, M_^/M,, = 2.68. The material was soluble in NMP, THF and dimethylacetamide (DMAC). A 10% wt/wt solution in DMAC was prepared.

EXAMPLE 11 This example illustrates the synthesis of a PANDA- PEO diblock copolymer polymerized in the presence of 2- butoxyethanol .

Aniline (4.2 g, 0.045 moles), dinonylnaphthalene sulfonic acid (34.75 g, 0.075 moles), 2-butoxyethanol (34.75 g, 0.294 moles), methoxy poly(ethylene glycol), mono-amino terminated (Shearwater Polymers, Inc.; M„ = 5,000), (1.1 g, 2.2 x 10"* moles), and deionized (DI) water ( 150 ml ) were added to a 1 liter temperature controlled, jacketed reactor equipped with a separatory funnel and a magnetic stirrer. After the temperature of the mixture had dropped to 5°C, an aqueous solution of ammonium peroxidisulfate (12.8 g; 0.052 moles in 30 ml DI water) was added dropwise over about 30 min. The mixture became a brown slurry and, after about 1.5 hrs., a blue- green color started to appear. The mixture was stirred at 2° - 5°C for 20 hrs. and no thermal peak was observed. After the reaction was complete,- -the green slurry was transferred to a beaker (1 lit.) and allowed to separate into organic and aqueous layers . A bottom aqueous layer ( 100 ml ) was removed by a syringe and the organic layer was poured into excess methanol ( 500 ml ) to precipitate the polymer. The precipitated polymer was collected by vacuum filtration and washed with 400 ml methanol . After drying in air, a dark, black powder (14.6 g) was collected. The molecular weight of the polymer by GPC was: M„ = 112,400, M_^ = 76,100 and N^/M,, = 1.48. A solution of the material in tetrahydrofuran (THF) showed a λ_Bax at 763 nm at room temperature. The powder was partially soluble in methylethyl ketone and soluble in THF/hexane mixture.

EXAMPLE 12 This example illustrates the synthesis of the PANDA and N-phenyl-lauramidoaniline diblock copolymer ( PANDA-(N-phenyl-lauramidoaniline ) ) polymerized in the presence of n-butanol.

N-phenyl-4-lauramidoaniline (CH₃(CH₂ )₁₀C0-ADPA) , (0.39 g, 0.00106 moles), n-butanol (60 ml, 0.655 moles), pTSA 3.3 g, 0.0173 moles) and 20 ml DI water were added to a 150 ml flask. The mixture was initially a blue emulsion, but after 30 min. in an ice bath, a gray powder precipitated from the mixture. The precipitate re- dissolved upon warming the mixture to room temperature. Ammonium peroxidisulfate (3.36 g, 0.0147 moles) was added and, after stirring at room temperature for 2 min. , the mixture became a green emulsion. Aniline (1.0 ml, 0.0109 moles) was added and the mixture immediately became a brown emulsion that, after 5 min. , became a blue emulsion and after 1 hr. became a dark green slurry. The mixture was stirred at room temperature for 22 hrs. and an aqueous phase and an organic phase formed. The aqueous phase was removed by pipet and the organic phase was washed twice with DI water (2 x 50_.ml). A green emulsion (46 g) was obtained as a product.

Molecular weight of the solids in the emulsion was determined by GPC and M,, = 19,300, M„ = 8,410 and M_^/M_^ = 2.3.

A film was cast from the green emulsion onto a Mylar® sheet having two spaced, gold stripe electrodes. The resistance of a film having a length between electrodes of 2.0 cm, a width of 0.5 cm and a thickness of 2 x 10"⁴ cm, was measured to be 1.9 kiloOhms . The electrical conductivity was calculated to be 0.7 S/cm.

The copolymer synthesized as described above was dedoped and characterized by nuclear magnetic resonance (NMR) spectroscopy. The green polymer emulsion (10 g), methanol (10 g, 0.3125 moles), and tri-iso-propylamine (1.3 g, 0.0146 moles) were added to a 100 ml round flask equipped with a magnetic stirring bar. After stirring at room temperature for 30 min. the slurry was placed in three tubes and centrifuged. The top liquid layer was decanted off. Methanol (7 ml, 0.174 moles) was added to each tube with mixing and the top liquid layer decanted off after recentrifuging. This wash was repeated. The unit from each tube was recovered by vacuum filtration onto filter paper and washed with additional methanol ( 20 ml, 0.498 moles). After drying in air, a blue purple powder (0.15 g) was collected. A small amount of the powder was added to dimethylsulfoxide deuterated in all six protons (D⁶-DMS0). After it was dissolved, a proton NMR spectra was obtained on the sample as shown in Figure 2. The broad peak between 6.7 ppm and 7.3 ppm is assigned to the hydrogen on both benzyl and quinone moieties of polyaniline. The peak between 1.1 ppm and 1.3 ppm is assigned to the hydrogen on the aliphatic portion of N-phenyl-4- lauramidoaniline. The peak at about 0.8 ppm is assigned to the terminal methyl group of the N-phenyl-4- lauramidoaniline (NPLA); the peak.. at about 1.3. is assigned to the alkyl group of the NPLA; the peak between 2.2 ppm and 2.4 ppm is assigned to the hydrogen on the - CH₂C0- of NPLA. The large peak at about 2.5 is assigned to DMSO; the large peak at about 3.1 is assigned to water; the two large peaks at about 3.4 and 4.1 are the residual solvent and the low, broad peak at about 7.0 is assigned to polyaniline. The NMR spectra demonstrates the presence of polyaniline and N-phenyl-4-lauramidoaniline in the solid copolymer.

The copolymer was then dissolved in tetrahydrofuran (THF) and its UV spectra was obtained. The dedoped copolymer (0.015 g), prepared as described above, was added to THF (2.0 ml, 0.025 moles) and about one-half of the solids dissolved, resulting in a concentration of about 0.5% wt/wt. The solution was filtered through a 0.45 micron filter and the UV spectra from 250 nm - 900 nm was obtained on a Perkin-Elmer Lambda-6 UV-Vis spectrophotometer. The spectra, as shown in Figure 3, indicates an absorption maximum (λ_Bax) at about 600 nm - 650 nm in THF, which is close to that of dedoped polyaniline (λ_B(Ut « 600 nm - 650 nm). The copolymer was soluble in THF, whereas polyaniline base alone is not. EXAMPLES 13 - 14 This example illustrates the synthesis of the PANDA and PANDBSA triblock copolymers of polypropylene ( PANDA-PPO-PANDA and PANDBSA-PPO-PANDBSA ) in a non- aqueous system with the use of an organic-soluble chemical oxidant.

Aniline (2.8 g, 0.03 moles), di-ADPA-terminated- polypropylene (1.0 g), (M„ = 4,000), toluene (30. ml, 0.28 moles), DΝΝSA (16.55 g, 0.035 moles), 2-butoxyethanol (16.55 g, 0.14 moles) were added to a stirred 250 ml flask. A solution of DCCBQ (8.34.g, 0.37 moles) in 50 ml toluene (0.47 moles toluene) was added dropwise over 10 min. After the solution was stirred at room temperature for 25 hours it was poured into a mixture of acetone ( 800 ml) and methanol (200 ml), but only a small amount of the copolymer precipitated. The precipitated copolymer was collected by filtration, washed with three aliquoets of 100 ml methanol and air dried for one day. The green solid that was collected (1.53 g ) had a weight average molecular weight as measured by GPC of M„ = 96,000 and a number average molecular weight of M_n = 62,000, Mw/Mn = 1.55.

The filtered solution was evaporated to dryness to recover a black powder that was washed with three aliquoets (each 300 ml) of methanol and air dried for 24 hours. 5.4 g of green solid was collected from the filtrate. The molecular weight of this material was, M„ = 96,000, M„ = 58,000, My/M,, = 1.64. Both the precipitated and soluble materials were soluble in THF. The reaction described above was repeated, except that 97% dodecylbenzenesulfonic acid (10.01 g, 0.03 moles), was used in place of the DΝΝSA. After 25 hours, the solution was poured into methanol ( 800 ml ) containing 30 ml water. The precipitated material was collected by vacuum filtration, washed with three aliquoets (each 100 ml) of methanol and air dried for 24 hours. 4.7 g of black solids was collected. The molecular weight of the material as measured by GPC was, M„ = 148,000, M„ = 79,000 and My/NL, = 1.87. The product was soluble in THF an_d in NMP (with 0.02 N ammonium formate ) .

EXAMPLE 15 This compares the properties of a polyaniline- poly( ethylene glycol)- polyaniline triblock copolymer of the present invention with a copolymer prepared by the method of Japanese Patent Publication 6-256509 to Oka and using the same non-ICP block.

The purpose of this example is to provide a direct comparison between a triblock copolymer prepared by the emulsion polymerization method of the present invention and a copolymer produced by the method disclosed in Japanese Pat. Publ. No. 6-256509 to Oka. The same aniline and non-ICP block were used in each method and the non-ICP block was selected to be very similar to that used in one example of the Oka Publication. An amine- terminated poly( ethylene glycol) having a molecular weight of about 500 was used in this example compared with Example No. 1 of the Oka publication, in which an amine-terminated poly(ethylene glycol) having a molecular weight of about 400 was used.

Preparation of (PANI )-( PEG500 )-( PANI ) triblock copolymer by the method of the present invention:

Poly( ethylene glycol) (0.85 g, of o,o'-Bis(2- aminopropyl) polyethylene glycol, PEG500, available from Fluka Chemical Co.), deionized water (300 ml), aniline (8.5 g), dinonylnaphalenesulfonic acid (DNNSA; 69.5 g), 2-butoxyethanol (69.5 g), (a 50:50 solution of DNNSA in 2-butoxyethanol is available as Nacure® 1051 from King Industries, Inc.), were added to a 1 liter jacketed glass kettle reactor in an ice bath and cooled to 0° - 2^βC. An ammonium peroxidisulfate solution (25.6 g (NH₄)₂S₂0₈ in 60 ml DI water) was added dropwise to the mixture in the reactor over one hour. The mixture was initially a brown emulsion that became a green emulsion after stirring at 0^βC for a total of 2 hours, and was then stirred at 0°C for two days. The organic layer that separated to the top of the mixture was poured into excess methanol (1.5 liters) and the precipitated product collected by vacuum filtration and washed twice with methanol (2 x 250 ml) and once with DI water (50 ml ) . After drying in air for one day, 36 g of green-blue chunks was collected.

The product was soluble i -THF. A solution of the material in THF was used to determine the molecular weight of the copolymer by the GPC method described in Example 1. The results showed a one-component molecular weight distribution with that component having M„ = 138,000, l = 65,000 and N^/M., = 2.12.

A film was then cast from the copolymer (0.05 g) in a solution of THF (1.0 g) and the conductivity was measured by the method described in Example 4. The film had a conductivity of 4 x 10"³ S/cm.

The solubility of the copolymer was then determined in xylenes and chloroform. Two samples of the solid copolymer (each 0.12 g) were mixed separately with xylenes (1.01 g, from Fisher Scientific) and with chloroform (1.01 g, from Burdick & Jackson). All of the solid polymer was dissolved in each solution to produce clear, green solutions. This indicates that the solubility of the DNNSA-doped (PANI )-(PEG500)-( PANI ) copolymer of the present invention is at least 10% wt/wt in xylenes and in chloroform.

Preparation of (PANI )-(PEG500)-( PANI ) triblock copolymer by the method of Japanese Pat. Publ. 6-256509:

Poly(ethylene glycol), (1.0 g, of o,o'-Bis(2- aminopropyl) polyethylene glycol, PEG500, available from Fluka Chemical Co.), deionized water (30 ml) and ammonium peroxidisulfate (24.5 g), were added to a 250 ml flask equipped with a magnetic stirrer and the mixture became a clear, colorless solution at room temperature. Upon cooling the solution in an ice bath for 30 min. , some solids precipitated. Aniline (10 g) was added to a solution of concentrated HC1 (50 ml of 12.1 N acid) and DI water (50 ml ) . The solution became light brown and upon cooling in an ice bath for 30 min. , some of the aniline salt precipitated from the solution and the mixture became a slurry. The HCl/aniline slurry was added to the PEG solution in the- flask dropwise over one hour. The mixture in the flask became a pink slurry during the first 5 min., then turned sky blue and, after 20 min., became a blue-green slurry. After addition of the aniline slurry, the flask contents exhibited an exotherm in which the temperature rose from about 2° - 5^βC to about 40°C. The mixture was stirred in the ice bath for another six hours . The solid product was then collected by vacuum filtration, washed with 100 ml of 2N HC1 and dried in air overnight (14 hrs.). The dried product (11.5 g) was in the form of black chunks.

The product was partially soluble in THF. A solution of the material in THF was used to determine the molecular weight of the copolymer by the GPC method described in Example 1. The results showed a two- component molecular weight distribution with one component having M„ = 78,000, M„ = 48,000 and M./M,, = 1-6, and the second component having M„ = 5,800, M„ = 3,200 and / - 1.8. One half of the product (5.5 g ) was de-doped by mixing it with 150 ml of 5% wt/wt aqueous ammonium hydroxide solution and stirring for 2 hours. The product was collected by vacuum filtration, washed twice with 50 ml of the same 5% ammonium hydroxide solution and air dried for one day. The black powder (2.5 g) that resulted was soluble in NMP. The molecular weight of this material was determined and the results again showed a two-component molecular weight distribution with one component having M„ = 83,000, M„ = 55,000 and ^/ ,, = 1.5, and the second component having M,, = 7,100, M„ = 4,400 and M_^/M., - 1.6.

The other half of the product (5.5 g) was purified by slurrying with 100 ml THF and stirring for 2 hours . The solids were collected by vacuum filtration, washed three times with THF (3 x 80 ml) and air dried for 2 hours. The molecular weight of the green powder (1.25 g) that was collected was measured by he GPC method described in Example 1 and the results again showed a two-component molecular weight distribution with one component having M_^ = 81,000, M_n = 54,000 and l ,/M_n = 1-5, and the second component having M„ = 4,600, M„ = 3,300 and M» = 1-4.

Films were cast from the de-doped copolymer (0.05 g) in a solution of THF (1.0 g), and from the de-doped copolymer (0.05 g) in a solution of THF (5.0 g) and Nacure® 1051 (0.1 g). The conductivity of these films was measured by the method described in Example 4. The film containing the de-doped copolymer was non- conductive. The resistance of the film cast from the dedoped copolymer that had been doped with DNNSA post- synthesis, was close to the sensitivity limit of the meter ( 1 x 10"⁹ Ohms ) , which would correspond to a conductivity of less than 1 x 10^"δ S/cm.

The solubility of the de-doped copolymer and of the de-doped copolymer after re-doping with DNNSA were determined in xylene and chloroform.

A sample of the de-doped polymer (0.019 g), prepared as described above, was mixed with xylenes (2.0 g, from Fisher Scientific). The de-doped copolymer was partially soluble in the xylenes, but many particles remained undissolved. This indicated a solubility for the de-doped copolymer in xylenes of less than 1% wt/wt. Another mixture was prepared of the de-doped copolymer (0.0191 g) and xylenes (9.5 g) as described above, except that Nacure® 1052 (0.05 g), was added to re-dope the copolymer with DNNSA. (Nacure® 1052 is a 50:50 mixture of DNNSA in xylene and is available from King Industries, Inc.). After thorough mixing at room temperature, particles remained undissolved. This indicates that the solubility of the DNNSA-doped copolymer as produced by the method of the Oka publication is less than 1% wt/wt.

Similar tests were carried out by mixing the dedoped copolymer (0.038 g) with chloroform (4 g, from Burdick & Jackson), although the copolymer was partially soluble in the solvent, many undissolved particles remained, indicating a solubility of less than 1% wt/wt for the de-doped copolymer in chloroform.

A mixture was prepared of the de-doped copolymer (0.0295 g) with chloroform (15 g) and DNNSA (0.075 g). After thorough mixing, undissolved particles remained in the mixture, indicating that the solubility of the copolymer re-doped with DNNSA was less than 1% wt/wt.

In view of the above, it will be seen that the several advantages of the invention are achieved and other advantageous results attained.

As various changes could be made in the above methods and compositions without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

Claims

What is claimed is:

1. An electrically conductive block copolymer comprising at least one polymer block that is an organic acid salt of an intrinsically conductive polymer and a non-intrinsically conductive block, the electrically conductive block copolymer having a solubility in xylene of at least about 1% wt/wt.

2. A copolymer as set forth in claim 1, wherein the non-intrinsically conductive block includes at least one monomer unit of a non-intrinsically conductive polymer and, ^"if the copolymer includes more than one polymer block that is an organic acid salt of an intrinsically conductive polymer, the non-intrinsically conductive block comprises a non-intrinsically conductive polymer of at least two monomer units.

3. A copolymer as set forth in claim 1, wherein the non-intrinsically conductive polymer block is covalently linked to the intrinsically conductive polymer block through a linkage group derived from a linkage group precursor selected from carbonyl compounds, quinones, halogenated compounds, phenols, alkoxides, ethers, amines, amides, ammonium salts, thiophenes, pyrroles, carbazoles, purines, viologens, acetylenes, thiols, phosphates, or phosphines.

4. A copolymer as set forth in claim 3, wherein the linkage group is derived from an amine group.

5. A copolymer as set forth in claim 4, wherein the amine group is derived from para-aminodiphenylamine.

6. A copolymer as set forth in claim 1 , wherein the intrinsically conductive polymer comprises monomer units of aniline, pyrrole, thiophene, acetylene, furan, indole, or mixtures thereof.

7. A copolymer as set forth in claim 1, wherein the intrinsically conductive polymer comprises aniline units .

8. A copolymer as set forth in claim 7, wherein the organic acid salt of an intrinsically conductive polymer comprises the para-toluene sulfonic acid salt of polyaniline, the dodecylbenzene sulfonic acid salt of polyaniline, or the dinonylnaphthalene sulfonic acid salt of polyaniline.

9. A copolymer as set forth in claim 6 , wherein the polymer block that is an organic acid salt of an intrinsically conductive polymer has a number average molecular weight of at least about 2,000.

10. A copolymer as set forth in claim 6, wherein the polymer block that is an organic acid salt of an intrinsically conductive polymer has a number average molecular weight of at least about 5,000.

11. A copolymer as set forth in claim 6, wherein the polymer block that is an organic acid salt of an intrinsically conductive polymer has a number average molecular weight of at least about 10,000.

12. A copolymer as set forth in claim 2, wherein the non-intrinsically conductive block comprises at least one monomer unit of poly( ethylene oxide), poly(propylene oxide), poly( ethylene glycol), or poly( acrylonitrile-co- butadiene) .

13. A copolymer as set forth in claim 1, wherein the copolymer has a solubility in xylene of at least about 2% wt/wt, or greater.

14. A copolymer as set forth in claim 1, wherein the copolymer has a solubility in xylene of at least about 5% wt/wt, or greater.

15. A copolymer as set forth in claim 1, wherein the copolymer has a solubility in xylene of at least about 10% wt/wt, or greater.

16. A copolymer as set forth in claim 4, wherein the non-intrinsically conductive polymer comprises poly( ethylene oxide) and the copolymer is 1% wt/wt soluble in chloroform when the degree of polymerization of the poly(ethylene oxide) is at least about 100 and the molecular weight of each polymer block that is an organic acid salt of an intrinsically conductive polymer is at least about 2,000.

17. A method for preparing an electrically conductive block copolymer, comprising combining

(a) a monomer of an intrinsically conductive polymer; (b) a chemical oxidant;

(c) a non-intrinsically conductive block precursor having at least one monomer unit of. a non-intrinsically conductive polymer that is covalently linked to at least one linkage group having an oxidation potential approximately equal to or less than the oxidation potential of the monomer of an intrinsically conductive polymer;

(d) water; and

(e) an organic solvent in which the organic acid, the non-intrinsically conductive polymer block precursor, the monomer of an intrinsically conductive polymer and the electrically conductive block copolymer are soluble and in which water is soluble in an amount of at least 6% wt/wt; thereby forming an electrically conductive block copolymer.

18. A method as set forth in claim 17, wherein, if the non-intrinsically conductive block precursor has two linkage groups, the non-intrinsically conductive polymer has at least one monomer unit of a non- intrinsically conductive polymer covalently linked to each of the two linkage groups.

19. A method as set forth in claim 17, wherein the linkage group is derived from a linkage group precursor selected from carbonyl compounds, quinones, halogenated compounds, phenols, alkoxides, ethers, amines, amides, ammonium salts, thiophenes, pyrroles, carbazoles, purines, viologens, acetylenes, thiols, phosphates, or phosphines.

20. A copolymer as set forth in claim 19, wherein the linkage group is derived from an amine.

21. A copolymer as set forth in claim 20, wherein the amine is para-aminodiphenylamine.

22. A method as set forth in claim 17, wherein the intrinsically conductive polymer comprises monomer units of aniline, pyrrole, thiophene, acetylene, furan, indole, or mixtures thereof.

23. A method as set forth in claim 17, wherein the intrinsically conductive polymer comprises monomer units of aniline.

24. A method as set forth in claim 20, wherein the organic acid salt of an intrinsically conductive polymer comprises the para-toluene sulfonic acid salt of polyaniline, the dodecylbenzene sulfonic acid salt of polyaniline, or the dinonylnaphthalene sulfonic acid salt of polyaniline.

25. A method as set forth in claim 17, wherein the polymer block that is an organic acid salt of an intrinsically conductive polymer has a number average molecular weight of at least about 2,000.

26. A method as set forth in claim 17, wherein the polymer block that is an organic acid salt of an intrinsically conductive polymer has a number average molecular weight of at least about 5,000.

27. A method as set forth in claim 17, wherein the polymer block that is an organic acid salt of an intrinsically conductive polymer has a number average molecular weight of at least about 10,000.

28. A method as set forth in claim 17, wherein the non-intrinsically conductive block comprises poly(ethylene oxide), poly(propylene oxide), poly(ethylene glycol), or poly( acrylonitrile-co- butadiene) .

29. A method as set forth in claim 17, wherein the electrically conductive block copolymer has a solubility in xylene of at least about 1% wt/wt, or greater.

30. A method as set forth in claim 17, wherein the electrically conductive block copolymer has a solubility in xylene of at least about 2% wt/wt, or greater.

31. A method as set forth in claim 17, wherein the electrically conductive block copolymer has a solubility in^" xylene of at least about 5% wt/wt, or greater.

32. A method as set forth in claim 17, wherein the electrically conductive block copolymer has a solubility in xylene of at least about 10% wt/wt, or greater.

33. A method as set forth in claim 23 , wherein the non-intrinsically conductive polymer comprises poly(ethylene oxide), the intrinsically conductive polymer comprises the dinonylnaphthalenesulfonic acid salt of polyaniline and the copolymer is 1% wt/wt soluble in chloroform when the degree of polymerization of the poly(ethylene oxide) is at least about 100 and the molecular weight of each polymer block that is an organic acid salt of an intrinsically conductive polymer is at least about 2,000.

34. An electrically conductive block copolymer made by the method of claim 17.

35. A method of preparing an electrically conductive block copolymer which comprises applying an oxidizing electrochemical potential to a monomer of an intrinsically conductive polymer in the presence of water, a non-intrinsically conductive block precursor having at least one monomer unit of a non-intrinsically conductive polymer that is covalently linked to at least one linkage group having an oxidation potential approximately equal to or less than the oxidation potential of the monomer of an intrinsically conductive polymer, and an organic solvent in which water is soluble in an amount of at least 6% wt/wt and in which the organic acid, the non-intrinsically conductive polymer block precursor, the monomer of an intrinsically conductive polymer and the electrically conductive block copolymer are soluble.

36. An electrically conductive block copolymer made by the method of claim 35.