Synthesis and effect of vanadium pentoxide nanoparticles on dielectric relaxation and ac conductivity of polyvinyl alcohol

Abstract

The dielectric parameters of polyvinyl alcohol containing 0–0.8 wt. % vanadium pentoxide are studied in the temperature range 20–150 °C at different frequencies: the dielectric constant, dielectric losses, and tangent of the angle of dielectric losses. Cole–Cole plots are used to determine the static dielectric constant and the dielectric constant at infinitely high frequency. The relaxation time is determined at different frequencies as a function of the tangent of the angle of dielectric losses versus the temperature. It is found that the relaxation properties follow the Arrhenius equation, the activation energy decreases with the vanadium pentoxide content in polyvinyl alcohol. An investigation of the dielectric relaxation as a function of temperature at constant frequency revealed two types of relaxation processes: dipole-segmented motion (α-relaxation) and side-chain dipole group motion (β-relaxation). The ac conductivity in the system polyvinyl alcohol––vanadium pentoxide is explained on the basis of the correlated barrier hopping model.