Author(s)

F. Bauer

Abstract

Ferroelectric polymers are the most recent class piezoelectric and pyroelectric materials developed. The most common piezoelectric polymers are PVDF, based on the monomer CH2-CF2 and copolymers PVDF with C2FgH The effects of frequency, temperature and hydrostatic pressure on the dielectric properties, molecular relaxations, and phase transitions of PVDF and a copolymer with 30% trifluoroethylene are recalled. Pressure causes large slowing down of the 3 molecular relaxations as well as large increases in the ferroelectric transition temperatures and melting points, but the magnitudes of the effects are different for the different "transitions". A unique application of these polymers as time-resolved dynamic stress gauges based on PVDF studies under very high pressure

Keywords