Microstructure and piezoelectric properties of PVDF films

Abstract

Abstract A new method for preparing extremely thin polyvinylidene fluoride (PVDF) films is described. The films consist of a non polar α–phase with a high uniaxial orientation of the molecules. Imbedded into the α–phase is a small volume fraction of the polar β–phase in a ribbon–like dispersion. Sandwiching those films and stretching them by about 20% or rolling them at temperatures up to 150°C induced the α → β phase transformation. The structure of the films was investigated by transmission electron microscopy. Measurements of the mechano–electric coupling coefficient were made by using a direct electric method.