Investigation of piezoelectricity distributions in poly(vinylidene fluoride) by means of quartz- or laser-generated pressure pulses

Abstract

The direct determination of charge, polarization, or piezoelectricity profiles in thin dielectrics is now possible if piezoelectrically generated pressure steps or pulses and laser-induced pressure pulses are employed. These recently developed high-resolution methods were applied to the same piezoelectric poly(vinylidene fluoride) (PVDF) samples. Comparison of the respective results demonstrates the feasibility, the advantages, and the limitations of the new techniques for the study of piezoelectricity distributions. It is confirmed that, for relatively low poling fields, the piezoelectric activity of thermopoled PVDF foils is often confined to a layer near the positively biased surface. The same effect is found for poling with a positive corona discharge. For high-field corona poling, the piezoelectric activity extends throughout the PVDF film.