DIELECTRIC AND PIEZOELECTRIC PROPERTIES OF POLYMER PIEZOELECTRIC 3-0 COMPOSITES

The mixture rules of dielectric constants of biphasic polymer-piezoele ctric composites with 3-0 connectivity have been modified by taking in to account the local field interactions. The solution of Laplace equat ion for the scalar potential inside and outside the piezoelectric sphe re dispersed in polymer matrix is obtained by using the proper boundar y conditions. Using the local electric held obtained from the potentia l, an expression for the dielectric constant of the composite is obtai ned. An approach is developed by which, using modified mixture rules, the piezoelectric constants of composites can be estimated. The develo ped expressions are functions of dielectric, elastic, piezoelectric co nstants and volume fractions of constituent phases and compare very fa vourably with the available experimental data.