Electrical properties of polyaniline and substituted polyaniline derivatives

Abstract

Polyaniline and substituted polyaniline derivatives which the ortho position hydrogen is substituted with CH 3, OCH 3 and Cl are studied. Both protonic acid doping (i.e. the addition of protons to the polymer chain without changing the number of electrons in the chain) and the acceptor doping (i.e., the number of electrons in the polymer chain is decreased by the acceptor which is iodine in this case) results on these samples show metallic conductivity. On the other hand, the signs of thermoelectric power are different. The sign of protonic acid doped polyaniline becomes negative upon doping, but the sign of the acceptor doped sample remains positive. The effect of the substitution of ortho hydrogen is more significant in the protonic acid doping than in the iodine doping. Electron affinity of the substituted molecules could affect the electronic structure of the polyaniline. The electrical conductivity and thermoelectric power measurement data as functions of doping concentration and temperature for these samples are presented.