Electrostriction of polarizable materials: Comparison of models with experimental data

A microscopic model is employed to relate the dielectric tensor to the microstructure of isotropic amorphous or cubic crystalline materials. Electrostriction is characterized by dielectric parameters that describe how the dielectric tensor varies with deformation and the resulting change in the microstructure. These dielectric parameters are obtained for small deformations, and expressed in terms of measurable, macroscopic properties. Unlike previous approaches, we avoid employing the Lorentz cavity approximation to determine the local polarization. Dipole sums are renormalized by treating the dielectric constant of the undeformed material as a known quantity. Predictions agree with our experimental data for different block copolymer films. Further progress in understanding electrostriction and developing improved models requires measuring the deformation dependence of the dielectric tensor for various materials under various conditions ~field strength and frequency, deformation frequency, temperature, etc.!. © 1998 American Institute of Physics. @S0021-8979~98!00601-X#