Unique pH dependent optical and magnetic properties of self doping type copolymers of aniline and aminonaphthalene derivatives with sulfonic groups

Summary form only given. Electrochemical and chemical copolymerization of aniline and aminonaphthalene derivatives having one or two sulfonic acid groups resulted in novel self doping type copolymers. Absorption spectrum of the resulting copolymers showed unique pH dependence as in the case of polyanifine but at different pH region. Deprotonation and protonation reactions of the nitrogen atom in polyaniline occur at pH about 3-4 but in the case of the self-doping copolymers they occur at pH 8-10. ESR measurements which indicated formation of polarons upon protonation also showed similar pH dependence. Susceptibility of some copolymers at low temperature showed marked decrease upon cooling down after indicating maximum value. This antiferromagnetic behavior was observed only after treatment with strong acid but not after treatments with neutral and basic solutions. Effects of acids, temperature, and polymerization conditions on the optical and magnetic properties have also been studied.