Investigation of piezoelectricity distribution in PVDF by means of pressure-pulse techniques

Abstract

Charge, polarization or piezoelectricity profiles in thin dielectrics can be directly determined by means of piezoelectrically-generated pressure steps^1-3 (PPS's) or pulses (PPP's) and laser-induced pressure pulses^4-6 (LIPP's). These recently developed high-resolution methods have been applied to the same piezoelectric PVDF samples, demonstrating the feasibility, advantages, and limitations of the new techniques for the study of piezoelectricity distributions. For relatively low poling fields, the piezoelectric activity of thermopoled PVDF films is often confined to a layer near the positively-biased surface. The same effect is observed for poling with a positive corona discharge. With high-field corona poling, the piezoelectric activity extends throughout the PVDF film.