Comparative Investigation of the Structure and Properties of Ferroelectric Poly(vinylidene fluoride) and Poly(vinylidene fluoride-trifluoroethylene) Thin Films Crystallized on Substrates

Poly(vinylidene fluoride) (PVDF) and copolymers of vinylidene fluoride and trifluoroethylene [P(VDF/TrFE)s] were deposited on silicon substrates, and their structure and properties were comparatively investigated. Compared to P(VDF/TrFE), which is the polymer material currently most dominant for ferroelectric thin-film devices applications, our beta-phase PVDF homopolymer thin film demonstrated several advantages, such as higher dielectric breakdown strength, improved polarization fatigue endurance, and larger ferroelectric polarization at elevated temperatures with improved thermal stability. The reasons for the observed different characteristics between the PVDF and P(VDF/TrFE) thin films were analyzed on the basis of their different structures and morphologies. The results indicate that the low-cost beta-phase PVDF homopolymer thin films have great potential as an alternative to P(VDF/TrFE) for ferroelectric and piezoelectric thin-film-device applications. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116: 3331-3337, 2010