Increment of dielectric constant in binary composite based on PVDF/clay system

Abstract

Binary composite films, with 10 wt% of barium doped porous clay heterostructure (Ba-PCH) in polyvinylidene difluoride, were fabricated by using mechanical mixing (Brabender) and hot pressing methods. The grain morphology of the composite films, as investigated by using the field emission scanning electron microscope, exhibits some agglomeration of Ba-PCH particles. The dielectric properties, as functions of frequency and temperature, were measured using a network analyzer. The dielectric constant of the composite film exhibits strong frequency and temperature dependence. The sharp drop of the dielectric constant is resulted, when temperature is decreased below the glass transition temperature of the polyvinylidene difluoride. The relaxation behaviors are analyzed carefully using the Arrhenius law and the other possible mechanisms and the study indicated that the dielectric behavior in these composite films is highly dominated by the electronic polarizability contributions.