Persistent polarization in poly(vinylidene fluoride). II. Piezoelectricity of poly(vinylidene fluoride) thermoelectrets

Abstract

Abstract The piezoelectricity of PVDF thermoelect rets formed with vacuum‐coated aluminum electrodes has been investigated in detail. The piezoelectricity depends on the β‐form crystal structure of PVDF homopolymer and copolymers. However, the piezoelectricity is not attributed to the stress dependence of the spontaneous polarization of β‐form crystals, but rather to the persistent polarization arising from trapped charges. The trapping mechanism is discussed.