Dielectric Relaxation in Polyvinylidene Fluoride (PVDF)/CsHSO4 Composites

A detailed dielectric spectroscopy study was performed on polyvinylidene fluoride (PVDF) and PVDF/CsHSO 4 composites at temperatures 220 K ≤ T ≤ 340 K and frequencies 10 Hz ≤ ν ≤ 10 5 Hz. The observed dielectric spectra were described as a contribution of two relaxation processes and dc conductivity. The obtained relaxation time for each process revealed a saddle-like temperature dependence which could not be fitted to a single Arrhenius or Vogel-Fulcher-Tammann equation. This unusual temperature behavior was successfully analyzed using an empirical model previously proposed to interpret similar nonmonotonic behavior of the relaxation time in confined dielectric systems. A brief discussion is presented about a possibility that some part of the amorphous regions is confined by the surrounding crystalline regions and vice versa in PVDF and the composites.