Polarization reversal associated with rotation of chain molecules in β-phase polyvinylidene fluoride

Abstract

The time dependence of polarization reversal in β-phase polyvinylidene fluoride has been measured under a step-function field up to 200 MV/m below room temperature. Fairly fast switching has been found to occur which might be accomplished by a 180° rotation of individual chains around their chain axes in the crystalline lamellae. The field dependence of the switching time is strong as indicated by a very high activation field of 1–2 GV/m or a large power law index of 8.0–10.5. The shape of switching transient has been investigated phenomenologically and by computer simulation on the basis of a nucleation and growth model. It is shown that the model is consistent with observations if one-dimensional growth and an appropriate ratio of growth velocity to nucleation probability are assumed. Effects of the size of nuclei and domains are examined.