Processible forms of electrically conductive polyaniline

What is claimed is:

1. A conductive polymeric composition comprising polyaniline of film-forming molecular weight in admixture with an effective protonating amount of a protonic acid, said protonic acid including a counterion that is functionalized so as to be soluble in nonpolar or weakly polar organic solvent and form a complex with the polyaniline having a conductivity greater than about 10.sup.-3 S-cm.sup.-1.

2. A conductive composition of claim 1 wherein the polyaniline is polyaniline having a molecular weight of greater than about 10,000 prepared by polymerizing an aniline of Formula 1: ##STR5## wherein: n is an integer from 0 to 4;

m is an integer from 1 to 5 with the proviso that the sum of n and m is 5;

R is the same or different at each occurrence and is alkyl, alkenyl, alkoxy, cycloalkyl, cycloalkenyl, alkanoyl, alkylthio, aryloxy, alkylthioalkyl, alkylaryl, arylalkyl, alkylsulfinyl, alkoxyalkyl, alkylsulfonyl, aryl, arylthio, arylsulfinyl, alkoxycarbonyl, arylsulfonyl, carboxylic acid, halogen, cyano, or alkyl substituted with one or more sulfonic acid, carboxylic acid, halogen, nitro, cyano or epoxy moieties; or any two R substituents taken together are an alkylene or alkenylene group completing a 3, 4, 5, 6 or 7 membered aromatic or alicyclic carbon ring, which ring may include one or more divalent heteroatoms of nitrogen, sulfur, sulfinyl, sulfonyl or oxygen.

3. A conductive polymeric composition according to claim 2 wherein said polyaniline is of the Formulas II to V: ##STR6## wherein: x is an integer equal to or greater than 1;

y is an integer equal to or greater than 0, with the proviso that the sum of x and y is greater than 8;

z is an integer greater than 1;

n is an integer from 0 to 4;

m is an integer from 0 to 4 with the proviso that the sum of n and m is 4;

R is the same or different at each occurrence and is alkyl, alkenyl, alkoxy, cycloalkyl, cycloalkenyl, alkanoyl, alkylthio, aryloxy, alkylthioalkyl, alkylaryl, arylalkyl, alkylsulfinyl, alkoxyalkyl, alkylsulfonyl, aryl, arylthio, arylsulfinyl, alkoxycarbonyl, arylsulfonyl, carboxylic acid, halogen, cyano, or alkyl substituted with one or more sulfonic acid, carboxylic acid, halogen, nitro, cyano or epoxy moieties; or any two R substituents taken together are an alkylene or alkenylene group completing a 3, 4, 5, 6 or 7 membered aromatic or alicyclic carbon ring, which ring may include one or more divalent heteroatoms of nitrogen, sulfur, sulfinyl, sulfonyl or oxygen.

4. A conductive polymeric composition according to claim 2 wherein m is equal to 5 and n is 0 such that the aniline is unsubstituted aniline.

5. A conductive polymeric composition according to claim 2 wherein n is greater than 0 such that said polyaniline is derived from substituted aniline.

6. A conductive polymeric composition according to claim 2 wherein R is the same or different at each occurrence and is alkyl or alkoxy having from 1 to about 12 carbon atoms, cyano, halogen or alkyl having from 1 to about 12 carbon atoms substituted with carboxylic acid or sulfonic acid substituents.

7. A conductive polymeric composition according to claim 6 wherein R is the same or different at each occurrence and is alkyl or alkoxy having form 1 to about 4 carbon atoms, or substituted alkyl having from 1 to about 4 carbon atoms wherein permissible substituents are alkyl, carboxylic acid and sulfonic acid substituents.

8. A conductive polymeric composition according to claim 7 wherein R is the same or different at each occurrence and is alkyl having from 1 to about 4 carbon atoms.

9. A conductive polymeric composition according to claim 6 wherein n is 1 to 4.

10. A conductive polymeric composition according to claim 9 wherein n is 1.

11. A conductive polymeric composition according to claim 3 wherein z is equal to or greater than about 5.

12. A conductive polymeric composition according to claim 11 wherein z is equal to or greater than about 10.

13. A conductive polymeric composition according to claim 12 wherein z is equal to or greater than about 15.

14. A conductive polymeric composition according to claim 3 wherein x is from 0 to about 8 and y is from 0 to about 8, with the proviso that the sum of x and y is at least about 8.

15. A conductive polymeric composition according to claim 14 wherein x is from about 1 to about 8 and y is from 0 to about 7, with the proviso that the sum of x and y is at least about 8.

16. A conductive polymeric composition according to claim 15 wherein x is from about 2 to about 8 and y is from 0 to about 6 with the proviso that the sum of x and y is at least about 8.

17. A conductive polymeric composition according to claim 1 wherein the protonic acid has a counterion that is soluble in non-polar or weakly polar organic solvent, molten or liquidified oligomer or polymer and said protonic acid is of the Formula VI or VII:

A--R.sub.1 VI

or ##STR7## wherein: A is sulfonic acid, selenic acid, phosphonic acid, a carboxylic acid, hydrogen sulfate, hydrogen selenate, or hydrogen phosphate;

n.sup.* is an integer from 0 to 5;

m.sup.* is an integer from 1 to 4 with the proviso that the sum of n.sup.* and m.sup.* is 5;

R.sub.1 is alkyl, alkenyl, alkoxy, alkanoyl, alkylthio, alkylthioalkyl, having from 1 to about 20 carbon atoms; or alkylaryl, arylalkyl, alkylsulfinyl, alkoxyalkyl, alkylsulfonyl, alkoxycarbonyl, carboxylic acid, where the alkyl or alkoxy has from 0 to about 20 carbon atoms; or alkyl having from 3 to about 20 carbon atoms substituted with one or more sulfonic acid, carboyxlic acid, halogen, nitro, cyano, diazo, or epoxy moieties; or a substituted or unsubstituted 3, 4, 5, 6 or 7 membered aromatic or alicyclic carbon ring, which ring may include one or more divalent heteroatoms of nitrogen, sulfur, sulfinyl, sulfonyl or oxygen such as thiophenyl, pyrolyl, furanyl, pyridinyl; or a polymer backbone to which a plurality of A units are attached;

R.sup.* is the same or different at each occurrence and is alkyl, alkenyl, alkoxy, cycloalkyl, cycloalkenyl, alkanoyl, alkylthio, aryloxy, alkylthioalkyl, alkylaryl, arylalkyl, alkylsulfinyl, alkoxyalkyl, alkylsulfonyl, aryl, arylthio, arylsulfinyl, alkoxycarbonyl, arylsulfonyl, carboxylic acid, halogen, cyano, or alkyl substituted with one or more sulfonic acid, carboxylic acid, halogen, nitro, cyano, diazo or epoxy moieties; or any two R substituents taken together are an alkylene or alkenylene group completing a 3, 4, 5, 6 or 7 membered aromatic or alicyclic carbon ring or multiples thereof, which ring or rings may include one or more divalent heteroatoms of nitrogen, sulfur, sulfinyl, sulfonyl or oxygen.

18. A conductive polymeric composition according to claim 17 wherein m.sup.* is 4 and n.sup.* is 1.

19. A conductive polymeric composition according to claim 17 wherein A is sulfonic acid.

20. A conductive polymeric composition according to claim 1 7 wherein the protonic acid includes R.sub.1, which is alkyl, alkenyl, alkoxy, alkanoyl, alkylthio, alkylthioalkyl, having from 5 to about 16 carbon atoms, or alkyl having from 3 to about carbon atoms substituted with one or more sulfonic acid, carboxylic acid, halogen, nitro, cyano or epoxy moieties.

21. A conductive polymeric composition according to claim 17 wherein the protonic acid includes R.sup.*, which is the same or different at each occurrence and is alkyl, alkenyl or alkoxy, having from 3 to about 12 carbon atoms or alkyl substituted with one or more carboxylic acid, halogen, nitro, cyano or epoxy moieties.

22. A conductive polymeric composition of claim 1 additionally comprising a liquid solvent having a dielectric constant smaller than about 22.

23. A conductive polymeric composition according to claim 22 wherein said solvent is selected from the group consisting of organic solvent and molten or liquidified oligomer or polymer having a dielectric constant smaller than about 22.

24. A conductive polymeric composition according to claim 23 wherein said solvent has a dielectric constant smaller than about 15.

25. A conductive polymeric composition according to claim 24 wherein said solvent has a dielectric constant smaller than about 10.

26. A conductive polymeric composition according to claim 24 wherein said solvent is a solvent selected from the group consisting of alkanes and alkenes having from about 5 to about 12 carbon atoms, mineral oil, aromatics, halogenated aromatics, halogenated alkanes, and aliphatic alcohols, alkyl ethers and ketones having from 4 to about 12 carbon atoms, cycloalkanes, cycloalkenes, carbontetrachloride, carbon disulfide, chloroform, bromoform, dichloromethane, morpholine, aniline, alkylbenzenes, xylene, toluene, decahydronaphthalene, styrene, and naphthalene.

27. A conductive polymeric composition according to claim 26 wherein said solvent is selected from the group consisting of alkanes and alkenes having from about 5 to about 12 carbon atoms, mineral oil, aromatics, halogenated aromatics, halogenated carbons, and aliphatic alcohols, alkyl ethers and ketones having from 4 to about 12 carbon atoms, carbontetrachloride, chloroform, aniline, xylene, toluene, decahydronaphthalene and styrene.

28. A conductive polymeric composition according to claim 1 wherein the protonic acid is a liquid having a dielectric constant equal to or smaller than about 22 and wherein said protonic acid serves as solvent as well.

29. A conductive polymeric composition according to claim 1 wherein said solvent is a liquidified or molten oligomer or polymer selected from the group comprising hexatriacontane, dotriadecane, octadodecane, polyethylenes, isotactic polypropylene, polystyrene, poly(ethylvinylacetate), polybutadiene, polyisoprene, ethylenevinylene-copolymers, ethylene-propylene copolymers, poly(ethyleneterephthalate), poly(butyleneterephthalate), nylon 12, nylon 8, nylon 6, and nylon 6.6.

30. A conductive polymeric composition according claim 1 wherein said conductivity is at least about 10.sup.-2 S-cm.sup.-1.

31. A conductive polymeric composition according to claim 30 wherein said conductivity is at least about 10.sup.-1 S-cm.sup.-1.

32. A conductive polymeric composition according to claim 31 wherein said conductivity is at least about 1 S-cm.sup.-1.

33. A conductive polymeric composition according to claim 1 wherein said conductive polymeric composition is a solution.

34. A conductive polymeric composition according to claim 1 wherein said conductive polymeric composition is a plasticized solid.

35. A conductive polymeric composition according to claim 22 wherein said conductive polymeric composition comprises less than 10 weight percent of the total of polymeric composition plug liquid solvent.

36. A conductive polymeric composition according to claim 35 wherein said conductive polymeric composition comprises less than 1 weight percent of the total of polymeric composition plus liquid solvent.

37. A conductive polymeric composition according to claim 36 wherein said conductive polymeric composition comprises less than 0.1 weight percent of the total of polymeric composition plus liquid solvent.

38. A conductive polymeric composition of claim 1 comprising polyaniline and dodecylbenzenesulfonic acid.

39. A conductive polymeric composition according to claim 38 having a conductivity equal to or greater than about 10.sup.-1 S-cm.sup.31 1.

40. A conductive polymeric composition according to claim 39 having a conductivity equal to or greater than about 10.sup.1 S-cm.sup.-1.

41. A conductive polymeric composition according to claim 1 prepared in situ by emulsion polymerization.

42. A conductive polymeric composition according to claim 22 wherein said liquid solvent is a monomer.

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BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to conductive polymers and particularly to the use of functionalized protonic acids to induce processibility of electrically conductive substituted or unsubstituted polyanilines, and to induce solubility of electrically conductive substituted or unsubstituted polyanilines in organic liquids or fluid (melt) phases of solid polymers. Other aspects of this invention relate to the resulting solutions of electrically conductive substituted or unsubstituted polyanilines in organic liquids, to methods of forming such solutions and to methods of using such solutions to form conducting polymer articles and methods of using such solutions as electrically conducting liquids. Yet other aspects relate to solid phase polymers containing these protonic acids as plasticizers and their use in forming conductive articles.

2. Prior Art

There has recently been an increased interest in the electrical conductivity and electrochemistry of polymeric systems. Recently, work has intensified with emphasis on polymers having extended conjugation in the backbone chain.

One conjugated polymer system currently under study is polyaniline. Kobayashi Tetsuhiko et al., J. Electroanal Chem., "Electrochemical Reactions Concerned With electrochromism of Polyaniline Film-Coated Electrodes," 177 (1984) 281-291, describes various experiments in which spectro electro-chemical measurement of a polyaniline film coated electrode were made. French Patent No. 1,519,729, French Patent of Addition 94,536; U.K. Patent No. 1,216,549; "Direct Current Conductivity of Polyaniline Sulfate," M. Donomedoff, F. Kautier-Cristojini, R. ReSur-vail, M. Jozefowicz, L. T. Yu, and R. Buvet, J. Chim. Phys. Physicohim. Brol., 68, 1055 (1971); "Continuous Current Conductivity of Macromolecular Materials," L. T. Yu, M. Jozefowicz, and R. Buvet, Chim. Macromol.,1,469 (1970); "Polyaniline Based Filmogenic Organic Conductive Polymers," D. LaBarre and M. Jozefowicz, C. R. Read. Sci., Ser. C, 269, 964 (1969); "Recently Discovered Properties of Semiconducting Polymers," M. Jozefowicz, L. T. Yu, J. Perichon, and R. Buvet, J. Polym. Sci., Part C, 22, 1187 (1967); "Electrochemical Properties of Polyaniline Sulfates," F. Cristojini, R. De Surville, and M. Jozefowicz, Cr. Read. Sci ., S r C, 268, 1346 (1979 ; "Electrochemical Cells Using Protolytic Organic Semiconductors," R. De Surville, M. Jozefowicz, L. T. Yu, J. Perichon, R. Buvet, Electrochem. Ditn. 13, 1451 (1968); "Oligomers and Polymers Produced by Oxidation of Aromatic Amines," R. De Surville, M. Jozefowicz, and R. Buvet, Ann. Chem. (Paris), 2,5 (1967) "Experimental Study of the Direct Current Conductivity of Macromolecular Compound," L. T. Yu, M. Borredon, M. Jozefowicz, G. Belorgey, and R. Buvet, J. Polym. Sci. Polym. Symp., 16, 2931(1967); "Conductivity and Chemical Properties of Oligomeric Polyaniline," M. Jozefowicz, L. T. Yu, G. Belorgey, and R. Buvet, J. Polym. Sci., Polym. Symp., 16, 2934 (1967); "Products of the Catalytic Oxidation of Aromatic Amines," R. De Surville, M. Jozefowicz, and R. Buvet, Ann. Chem. (Paris), 2, 149 (1967); "Conductivity and Chemical Composition of Macromolecular Semiconductors," Rev. Gen. Electr., 75 1014 (1966); "Relation Between the Chemical and Electrochemical Properties of Macromolecular Semiconductors," M. Jozefowicz and L. T. Yu, Rev. Gen. Electr., 75, 1008 (1966); "Preparation, Chemical Properties, and Electrical Conductivity of poly-N-Alkyl Anilines in the Solid State," D. Muller and M. Jozefowicz, Bull. Soc. Chem. Fr., 4087 (1972).

U.S. Pat. Nos. 3,963,498 and 4,025,463 describe oligomeric polyanilines and substituted polyanilines having not more than 8 aniline repeat units which are described as being soluble in certain organic solvents and which are described as being useful in the formation of semiconductors compositions. European Patent No. 00117717 is an apparent improvement in the compositions of U.S. Pat. Nos. 3,963,498 and 4,025,463 and states that the polyaniline can be formed into a latex composite through use of the oligomers of polyaniline and a suitable binder polymer.

High molecular weight polyaniline has emerged as one of the more promising conducting polymers, because of its excellent chemical stability combined with respectable levels of electrical conductivity of the doped or protonated material. Processing of polyaniline high polymers into useful objects and devices, however, has been problematic. Melt processing is not possible, since the polymer decomposes at temperatures below a softening or melting point. In addition, major difficulties have been encountered in attempts to dissolve the high molecular weight polymer.

Recently, it was demonstrated that polyaniline, in either the conducting emeraldine salt form or the insulating emeraldine base form, can processed from solution in certain strong acids to form useful articles (such as oriented fibers, tapes and the like). By solution processing from these strong acids, it is possible to form composites, or polyblends of polyaniline with other polymers (for example polyamides, aromatic polyamides (aramids), etc.) which are soluble in certain strong acids and thereby to make useful articles. "Electrically Conductive Fibers of Polyaniline Spun from Solutions in Concentrated Sulfuric Acid," A. Andreatta, Y. Cao, J. C. Chiang, A. J. Heeger and P. Smith, Synth. Met., 26, 383 (1988 ; "X-Ray Diffraction of Polyaniline," Y. Moon, Y. Cao, P. Smith and A. J. Heeger, Polymer Communications, 30, 196 (1989); "Influence of the Chemical Polymerization Conditions on the properties of Polyaniline," Y. Cao, A. Andreatta, A. J. Heeger and P. Smith, Polymer, 30, 2305 (1990); "Magnetic Susceptibility of Crystalline Polyaniline," C. Fite, Y. Cao and A. J. Heeger, Sol. State Commun., 70, 245 (1989); "Spectroscopy and Transient Photoconductivity of Partially Crystalline Polyaniline," S. D. Phillips, G. Yu, Y. Cao, and A. J. Heeger, Phys. Rev. B , 10702 (1989); "Spectroscopic Studies of Polyaniline in Solution and in the Solid State," Y. Cao and A. J. Heeger, Synth. Met. 32, 263, (1989); "Magnetic Susceptibility of One-Dimensional Chains in Solution," C. Fite, Y. Cao and A. J. Heeger, Solid State Commun., 71, 607 (1990); "Electrically Conductive Polyblend Fibers of Polyaniline and Poly(p-phenylene terephthalamide)," A. Andreatta, A. J. Heeger and P. Smith, Polymer Communications, 31, 275 (1990); "Polyaniline Processed From Sulfuric Acid and in Solution in Sulfuric Acid: Electrical, Optical and Magnetic Properties," Y. Cao, P. Smith and A. J. Heeger in Conjugated Polymeric Materials: Opportunities in Electronics, Opto-electronics, and Molecular Electronics, ed. J. L. Bredas and R. R. Chance (Kluwer Academic Publishers, The Netherlands, 1990).

U.S. Pat. No. 4,983,322 describes solutions and plasticized co positions of electrically conductive substituted and unsubstituted polyanilines and methods of forming such solutions or compositions and use of same to form conductive articles. The polyaniline materials were made soluble by the addition of an oxidizing agent such as FeCl.sub.3. Since the resulting compounds are charge transfer salts, highly polar solvents were required; specifically solvents were needed with dielectric constants equal to or greater than 25 and with dipole moments equal to or greater than 3.25.

Starting with the insulating emeraldine base form, polyaniline can be rendered conducting through two independent doping routes:

(i) Oxidation either electrochemically (by means of an electrochemical charge transfer reaction) or chemically (by means of chemical reaction with an appropriate oxidizing agent such as FeCl.sub.3);

(ii) Protonation through acid-base chemistry by exposure to protonic acids (for example, in aqueous environment with pH less than 2-3).

These two different routes lead to distinctly different final states. In (i), the oxidation causes a change in the total number of .pi.-electrons on the conjugated chain and thereby renders it conductive. In (ii), there is no change in the number of electrons; the material is rendered electrically conductive by protonation of the imine nitrogen sites.

In the general field of conducting polyaniline, it was believed impossible to dope a high molecular weight polyaniline to the extent that it becomes a semiconductor or conductor and thereafter dissolve or plasticize the conductive form of polyaniline in common nonpolar or weakly polar organic solvents. As used herein, the terms "to plasticize" and a "plasticized composition" refer to the process and product in which a solid polymer includes an admixed liquid or semisolid phase to an extent sufficient to render the solid polymer flexible (softened) and not brittle. The liquid or semisolid additive is known as a "plasticizer." The nature of plasticized materials is described in more detail in Harry R. Allcock and Frederick W. Lampe, Contemporary Polymer Chemistry, Prentice-Hall, Inc. Englewood Cliffs, N.J. (1981), p. 13.

In the absence of solutions or plasticized forms, comprising common nonpolar or weakly polar liquids, or otherwise processible forms, the ability to form useful conductive articles out of conductive polyaniline, or composites or polyblends of conductive polyaniline with other polymers (for example polyethylene, polypropylene, polystyrene, elastomers, poly(ethylvinylacetate), etc.) is restricted. Thus, a need exists for techniques and materials to facilitate the fabrication of shaped conductive polyaniline articles, especially articles made from bulk material (conductive polyanilines and/or composites, or polyblends of conductive polyaniline with other polymers) and films, fibers and coatings.

SUMMARY OF THE INVENTION

One aspect of the present invention relates to solutions and plasticized polymeric compositions comprising polyaniline of film and fiber forming molecular weight, a solvent or plasticizing liquid selected from the group consisting of nonpolar or weakly polar organic solvents, or molten or liquidified oligomers or polymers, and a functionalized protonic acid solute in which the counter-ion has been functionalized to be compatible with nonpolar or weakly polar organic solvents. As used herein, a "functionalized protonic acid" is a protonic acid, generally denoted as H.sup.+ (M.sup.- --R.sub.p), in which the counterion anionic species, (M.sup.- --R.sub.p), contains the R.sub.p functional group or a connection to a polymer backbone which is chosen to be compatible with nonpolar or weakly polar organic liquids, or molten or liquidified oligomers or polymers. An illustrative example would be the following:

M.sup.- =SO.sub.3 --

R.sub.p =dodecyl-benzene.

In cases where the functionalized protonic acid is a liquid, it may replace some or all of the solvent or plasticizing liquid as well.

Another aspect of the present invention relates to a method of forming the solution or plasticized composition of this invention by dissolving said polyaniline, said functionalized protonic acid, either separately or in combination as a protonated conductive polyaniline, in said solvent (plasticizing liquid).

Yet another aspect of this invention relates to a method of forming a conductive article from the solution or plasticized composition of this invention which compromises the steps of:

a. forming a solution or plasticized composition comprising polyaniline, a solvent selected from the group consisting of nonpolar or weakly polar organic liquids and a functionalized protonic acid solute; and

b. removing all or a portion of said solvent from said solution or plasticized composition after or concurrent with shaping the solution into the desired article.

Yet another aspect of this invention relates to a method of forming a conductive article from the solution or plasticized composition of this invention which compromises the steps of:

a. forming a solution or plasticized composition comprising polyaniline, a solvent selected from the group consisting of non-polar or weakly polar organic liquid monomers and a functionalized protonic acid solute; and

b. polymerizing the monomer in said solution or plasticized composition, after or concurrent with shaping the solution into the desired article.

Yet another aspect of this invention relates to methods of forming a conductive article which is a composite, or polyblend of conductive polyaniline with other polymers (for example polyethylene, polypropylene, polystyrene, elastomers, poly(ethylvinylacetate), polyvinylchloride, etc.) from the solution or plasticized composition of this invention which compromises the steps of:

a. forming a solution or plasticized composition comprising polyaniline, a solvent selected from the group consisting of nonpolar or weakly polar organic solvents and a functionalized protonic acid solute and a suitable fraction of one or more other polymers (for example polyethylene, polypropylene, polystyrene, elastomers, poly(ethylvinylacetate), polyvinylchloride, etc.); and

b. removing all or a portion of said solvent from said solution or plasticized composition.

Yet another aspect of this invention relates to methods of forming a conductive article which is a composite, or polyblend of conductive polyaniline with other polymers (for example polyethylen