Ferroelectric reorientation of crystallites in polyvinylidene fluoride

Abstract
Orientation behaviors of the polyvinylidene fluoride film drawn-rolled and of its poled film were investigated. The biaxial orientation distribution function (BODF) was determined for various reflections through the intensity peak and two kinds of integral widths, δ(2θ) and δx, obtained in terms of X-ray diffraction method, and then BODF of the 6-axis was derived. Fourier coefficients, b, calculated from the BODF of the b-axis indicate that the dipole reorientation induced by poling about the c-axis is accommodated in the angular unit of 60°, which agrees with the 60″ switching model. Moreover, it was found that, during the poling process, crystallites are grown at their boundary parallel to the film surface and then crystallinity slightly increases.