Dielectric behaviour of thin films of beta-PVDF/PZT and beta-PVDF/BaTiO3 composites

Thin films of the composites formed between poly(vinylidene fluoride) (PVDF) and lead zirconium titanate (PZT) and also barium titanate with 0-3 connectivity, have been obtained by dispersion of the ceramic powder in a solution of PVDF in dimethylacetamide DMA. Evaporation of the solvent at 65 degrees C allowed crystallization of PVDF predominantly in the polar beta phase, regard less of the amount of PZT or BaTiO3 powder added upto 40 vol%. The relative permittivity and loss index values were determined for the pure components and for the composites with different ceramic contents, in the frequency range of 100 Hz to 13 MHz. An increase in PZT or BaTiO3 content resulted in an increase in the relative permittivity of the composites, and the experimental results are shown to be in good agreement with those calculated from the theoretical expression of Yamada et al. [1]. The de electrical conductivity of composites with different compositions was also determined.