A new class of ferroelectric polymetric material was developed by using the copolymers of polyvinylidene fluoride and trifluoroethylene, P(VDF- TrFE). Copolymer samples were subjected to high-energy electron irradiation, and the material appeared to be converted into a relaxor ferroelectric. The polarization hysteresis loop near the dielectric peak temperature became nearly non-hysteric, but gradually broadened and evolved into a normal ferroelectric hysteresis loop as the temperature was reduced. The dielectric constant as a function of temperature showed a broad dispersive peak in frequency, wiht the dispersion obeying the Vogel-Fulcher law. The dielectric constant was greatly increased with electron bombardment and a massive electrostriction was observed. Accompanying these changes were the resulting large electrically induced strain and high elastic energy density. The cause of these changes is presently believed to be the breakup of the coherent macro-polar regions containing the all-trans molecular conformation into micro-polar regions with increasing amorphous-crystalline interface as the sample was exposed to electron irradiation.

Date Published: 24 August 2000
PDF: 11 pages
Proc. SPIE 4073, Fifth European Conference on Smart Structures and Materials, (24 August 2000); doi: 10.1117/12.396414

Published in SPIE Proceedings Vol. 4073:
Fifth European Conference on Smart Structures and Materials
Pierre Francois Gobin; Clifford M. Friend, Editor(s)