Structural Change on Poling in a Piezoelectric Copolymer of Vinylidene Cyanide with Vinyl Acetate

Abstract
Structural change induced by an electric field in poly(vinylidene cyanide/vinyl acetate) is investigated by X-ray scattering. Upon poling with an electric field of 50 MV/m at 170°C (10°C below the glass transition temperature), the amorphous halo increases in intensity and becomes narrower in the direction parallel to the electric field; in the direction perpendicular to the electric field, no change is observed upon poling. The order induced by poling is discussed in connection with the piezoelectricity of the polymer.