Electrostrictive coefficients, expressed in terms of dielectric parameters and elastic constants, are obtained for elastic dielectrics. In most of the recent experiments concerning determination of electrostrictive parameters in elastic dielectrics, several researchers used incorrect equations without considering the contribution from the edge effect, the shear stresses and suitable boundary conditions. This led to wrong predictions of experimental results particularly for materials with high Poisson ratios. Errors in the estimation of induced strains, varying from an underestimation of 202% to an overestimation of 168%, have been pointed out in the case of polycarbonate (PC). However, the contribution from the boundary conditions is very difficult to predict correctly and hence it is still unresolved. The electromechanical properties of the nanometric interface are also discussed. Due to significant electrostrictive and piezoelectric characteristics of the nanometric interface, PC has a great potential for electromechanical applications as electromechanical transducers, sensors and actuators.