Relaxation behaviour of pristine and ZnO impregnated PS nanocomposite films using thermally stimulated depolarization current technique

Abstract

Thermally stimulated depolarization current studies of pristine and ZnO doped nanocomposite films (at 5, 10, 15 & 20 wt% of ZnO) have been investigated at different poling temperatures and polarizing fields. Peaks corresponding to glass transition temperature (α1 and α2-peaks) relaxation, space-charge relaxation (ρ-peaks) and γ-relaxation were observed in thermograms of pristine and doped films. The change in peak height and peak positions with increase in doping concentration and poling parameters i.e., EP & TP results to the trapping or detrapping of the charge carriers. The anomalous behaviour of PS/ZnO nanocomposite films towards TSD current spectra observed near the glass transition temperature indicates the phase transitions. Changes in different relaxations may be attributed to the structural deformation of the samples due to doping and supported by FTIR and SEM results. Moreover, some molecular parameters like activation energy (Ea) and relaxation times (τ) were estimated.