Dielectric relaxation in polyaniline-polyvinyl alcohol composites

The dielectric relaxation spectroscopy of HCl-doped PANI-PVA composites have been investigated in the temperature range 110-300 K and in the frequency range 200 Hz-10 MHz near the percolation threshold. A large value of the dielectric constant has been observed at high temperature and low frequency. The complex dielectric constant epsilon*(omega) has been described by the electric modulus M*(omega) = (1/epsilon*(omega)) = M'(omega) + iM(omega). The data of M*(omega) has been analysed by the stretched exponential decay of the electric field, phi(t) = exp - (t/tau(0))(beta), where 0 < beta less than or equal to 1. The temperature dependence of M'(omega) and M(omega) obey a single master curve with beta = 0.79. (C) 2002 Elsevier Science Ltd. All rights reserved.