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Abstract

A polyaniline is characterized by a nuclear magnetic resonance spectrum in its leuco form showing only two .sup.13 C peaks, indicating the substantal absence of chain branching, and preferably by a molecular weight (M.sub.p) above 90,000 and up to about 170,000 (more especially 100-140,000). Oriented films of such polyanilines in the protonated emeraldine oxidation state have electrical conductivities up to at least around 500 S/cm. They may be made by oxidizing aniline in aqueous solution with a persulfate under the combination of conditions that the acidity of the solution throughout the reaction is such that if its temperature is adjusted to 20.degree. C. it will have a pH in the range from about -0.2 to +3.0; that the temperature of the solution is in the range from -5.degree. to about -40.degree. C.; that the solution contains at least sufficient inert ionic solute to maintain it in the liquid state; and that the persulfate is added to the solution always at a rate corresponding to a total addition time of at least six hours (but preferably not over 36 hours) and in a molar ratio to the aniline in the range from 1.1:1 to 1.4:1.

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First Claim