Effects of particle size of BaTiO3 powder on the dielectric properties of BaTiO3/polyvinylidene fluoride composites

The effects of particle size of fine BaTiO3 powder on dielectric properties of BaTiO3/polyvinylidene fluoride (PVDF) composites were investigated. When the frequency of the applied field was less than 100 kHz, the dielectric constant and loss for BaTiO3/PVDF composites decreased with increasing BaTiO3 particle size. When the frequency was greater than 100 kHz, the opposite results were obtained. The resistivity increased with increasing BaTiO3 particle size, whereas the open areas of hysteresis loops decreased gradually. The degree of poling efficiency for BaTiO3/PVDF composites increased with increasing BaTiO3 particle size. The BaTiO3 particle size dependence of the dielectric properties of BaTiO3/PVDF composites is explained by space charge effects at the interface between BaTiO3 and PVDF, and domain configurations (single or multi-domain) of the BaTiO3 powders. (C) 2001 Kluwer Academic Publishers.