Comparative study of electrical properties of polyaniline films and polyaniline-polystyrene blends

Abstract

In this paper, a simple model classically used to describe electrical behavior in conducting polymers can take into account transport properties in polyaniline doped with two different counter-ions and in polyaniline-polystyrene blends. Conduction is mainly limited by hopping or tunneling between polaronic conducting clusters. When the structural disorder is less pronounced, a metallic contribution can occur near room temperature in series with the hopping/tunneling one. This heterogeneous picture used for unblended polyaniline can be applied to explain electrical blend properties above the percolation threshold when conduction occurs among completely connected polyaniline paths. Below the percolation threshold, the model has to take into account an additional contribution due to a hopping mechanism between large disconnected segments of polyaniline. It is shown that thermoelectric power reflects essentially the metallic behavior of the conducting clusters.