Ferroelectric PVDF polymer for high pressure and shock compression sensors

Abstract

Electrical processing of ferroelectric polymer (PVDF) with the Bauer cyclic poling method can produce individual films with a well-defined polarization up to 9 /spl mu/C/cm/sup 2/. The piezoelectric response PVDF stress gauges subjected to shock loading exhibits a reproducible behavior up to 25 GPa. Shock pressure profiles obtained with "in situ" PVDF gauges in high explosive in a detonation regime have been achieved. Observations of a fast superpressure of a few nanoseconds have raised the question of the loading path dependence of the PVDF response at high shock pressure levels. Consequently, studies of the piezoelectric behavior of PVDF gauges under impact loading using a two-stage light gas gun have been conducted. These results show that the PVDF response appears independent of the loading path up to 35 GPa. Furthermore, laser interferometry (VISAR) was used in some experiments to determine the particle velocity history of the PVDF gauge. The agreement between particle velocity and pressure histories is exceptional.