Correlation between electrical conductivity, thermal conductivity, and ESR intensity of polyaniline

Abstract

The thermal conductivity, electrical conductivity, and ESR spin concentration, [s], of chemically synthesized polyaniline have been measured. The thermal conductivity, electrical conductivity, and [s] showed maxima between pH=−1 and 1. The thermal conductivity exhibited a very good linear relationship with the electrical conductivity and log[s] when pH < 2. Such correlation leads to conclusion that thermal conduction occurs via the same mechanism as electrical conduction, i.e. the polarons mechanism. The Lorenz number computed for the sample with the highest conductivities was about 2.2×10 −7 V 2·K −2 which is higher, by an order of magnitude, than the theoretically expected value in metals. Such a high value of Lorenz number seems to support the idea of Focke and Wnek for the localized electronic states in polyaniline.