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 ϵ∗(ω) has been described by the electric modulus M∗(ω)=(1/ϵ∗(ω))=M′(ω)+iM″(ω). The data of M∗(ω) has been analysed by the stretched exponential decay of the electric field, φ(t)=exp−(t/τ0)β, where 0<β≤1. The temperature dependence of M′(ω) and M″(ω) obey a single master curve with β=0.79.