Application of percolation concepts to electrical conductivity of polyaniline–inorganic salt composites

Abstract

The dependence of the resistivity of protonated polyaniline–inorganic salt composites with the volume fraction of electrically conducting component was analyzed on the basis of percolation theory. A short analysis and a discussion of basic treatment in the evaluation of percolation parameters are included. Microscopical observations showed a non-uniform distribution of polyaniline particles in the composites. The composites of polyaniline sulfate with ammonium sulfate and potassium bromide have a low percolation threshold (<3 vol.% conducting component). This has been explained as a property of the segregated structure of the composites, which is formed because of a large difference in the particle sizes. Basic quantitative characteristics of the morphological structure have been obtained using the percolation model, as proposed by Ewen and Robertson, to explain the properties of thick film resistors.