Effect of particle size on the dielectric and piezoelectric properties of PbTiO3-polymer composites

Piezoelectric composites were prepared by mixing 67-vol% modified PbTiO₃ with a polymer. Composites were cured at 80°C for 10 h and poled with an electric field of 40 kV/cm for 1 h at 80°C. The dielectric constant, piezoelectric d₃₃, and hydrostatic coefficient d_h were found to increase with increasing particle size and the hydrostatic g_h coefficient decreased with increasing particle size of PbTiO₃. The hydrostatic figure of merit, d_h g_h was shown to be independent of particle size. Composites prepared with large particles were found to have lower breakdown strengths. The difference in properties with particle size indicates a probable change in connectivity due to variation of particle size and morphology