Liquid crystalline polyaniline derivatives

We synthesized three kinds of polyaniline derivatives, in which liquid crystalline substituents were introduced onto the nitrogen atom of the aniline unit (1), the benzene ring of the aniline unit (2), and the methine-bridging site linked with the diphenylamine unit (3). The third polymer was synthesized by dehydrative polycondensation between diphenylamine and the liquid crystalline moiety-including benzaldehyde using sulfuric acid according to the Rothemund reaction. Although all polymers were quite soluble in organic solvents such as THF and chloroform, only the second polymer with liquid crystalline group possessing a longer flexible methylene spacer (C=10) and the third polymer before DDQ treatment showed definite thermotropic liquid crystallinity.