ELECTROSYNTHESIS OF POLYPYRROLE IN A NEMATIC LIQUID-CRYSTAL

Pyrrole was anodically polymerized on platinum and indium-tin oxide electrodes in the nematic liquid crystal 4-cyano-4'-pentylbiphenyl containing an electrolyte. The nematic mixture was oriented with respect to the opposite working and counterelectrodes, which were separated by a 13-mu-m spacer, by previous silanization of the electrodes or by applying a sufficiently high electric field. Orientation of the nematic polymerization mixture induces shifts in the voltammetric peaks and the absorption spectral bands of the resulting films to more negative potentials and higher wavelengths, respectively. Some anisotropic conductivity was attained in films prepared in an oriented nematic environment. However, measurements along and across the film surface showed only small conductivity differences, and no evidence for crystallinity was obtained.