Electronic transport in composites based on polyaniline blended with cellulose acetate - A DC-conductivity and ESR analysis

Polyaniline protonated with camphorsulphonic acid or di-i-octyl phosphate was blended with cellulose acetate to produce composites with remarkably low percolation thresholds. As for generalized variable range hopping their conductivity follows: sigma = sigma(0)e(-(T0/T)gamma). For both systems the exponent gamma systematically increases with dilution from gamma similar or equal to 0.5 at high concentrations to gamma similar or equal to 0.8 near the percolation threshold. As shown recently, electron spin resonance (ESR) probes the conductivity of polyaniline on a microscopic scale. ESR-results are consistent with metallic behavior near room temperature and show little influence of dilution on the microscopic conductivity.