Effect of BaTiO3 nanowire on effective permittivity of the PVDF composites

Abstract

With the increasing application of barium titanate (BaTiO3) in polyvinylidene fluoride (PVDF), the evaluation of its dielectric properties has attracted the attention of many frontier scholars. In this paper, from the theoretical point of view, the effects of the aspect ratio and the concentrations of BaTiO3 nanowires on macroscopic dielectric properties were studied by the finite element method. Depending on the calculation results, some conclusions had been obtained: First, it was found that the effect of higher aspect ratios of nanowires on the effective permittivity of the composites was not significant when the aspect ratio of the nanowire filler exceeded 20. Second, when the permittivity of the BaTiO3 nanowires reaches about 3000, as the permittivity of the filler increases, the rate of change of the effective permittivity of the composite material gradually slows down, which indicates that nanowires with higher permittivity have little influence on the effective permittivity of the composites. Finally, by comparing with permittivity data of BT/PVDF composites in the literature, it was found that the simulation results have good consistency with the experimentally measured values. The above-mentioned results have shown that the composite may exhibit good dielectric properties at a low concentration (<30 vol. %) and low permittivity filler. Moreover, the electrostatic field can roughly represent the electric field of a low-concentration composite under a certain electric field strength.