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Stable, concentrated solutions of high molecular weight polyaniline and articles therefrom

United States Patent

5,981,695
November 9, 1999
View the Complete Patent at the US Patent & Trademark Office
Los Alamos National Laboratory - Visit the Technology Transfer Division Website
Stable, concentrated solutions of high molecular weight polyaniline. In order to process high quality fibers and other articles possessing good mechanical properties, it is known that solution concentrations of the chosen polymer should be in the range from 15-30% (w/w). Moreover, it is desirable to use the highest molecular weight consistent with the solubility properties of the polymer. However, such solutions are inherently unstable, forming gels before processing can be achieved. The present invention describes the addition gel inhibitors (GIs) to the polymer solution, thereby permitting high concentrations (between 15% and 30% (w/w)) of high molecular weight ((M.sub.w)>120,000, and (M.sub.n)>30,000) emeraldine base (EB) polyaniline to be dissolved. Secondary amines have been used for this purpose in concentrations which are small compared to those which might otherwise be used in a cosolvent role therefor. The resulting solutions are useful for generating excellent fibers, films, coatings and other objects, since the solutions are stable for significant time periods, and the GIs are present in too small concentrations to cause polymer deterioration. It is demonstrated that the GIs found to be useful do not act as cosolvents, and that gelation times of the solutions are directly proportional to the concentration of GI. In particular, there is a preferred concentration of GI, which if exceeded causes structural and electrical conductivity degradation of resulting articles. Heating of the solutions significantly improves solubility.
Mattes; Benjamin R. (Santa Fe, NM), Wang; Hsing-Lin (Los Alamos, NM)
The Regents of the University of California (Los Alamos, NM)
08/ 926,338
September 5, 1997
This invention was made with government support under Contract No. W-7405-ENG-36 awarded by the U.S. Department of Energy. The government has certain rights in the invention.