Transport properties of substituted derivatives of poly( aniline

Abstract

Aromatic ring and N-substituted derivatives of poly(aniline) have been synthesized by chemical peroxodisulphate oxidation method in aqueous trichloroacetic acid. UV-visible spectra of these polymers show hypsochromic shift with increase in dielectric constant of the solvent and due to substitution in the aromatic ring-.From temperature dependence of electrical conductivity, charge localization length and hopping distance are calculated and the effect of substituent and dopant on crystallinity is discussed. The introduction of substituent group either in a ring or at N-atoms produces space hinderance to internal rotation. The bulky dopant may distort or destroy the lattice and reduce the crystallinity. The temperature dependence of dielectric data and conductivity suggests that substituted derivatives of PANI are quasi ID-disordered state composed of 3D-metallic crystalline regions in 1D-localized amorphous regions.