Network structure in poly(vinylidene fluoride-trifluoroethylene) electrostrictive films

Recent studies of electron-irradiated copolymers of vinylidene fluoride and trifluoroethylene have demonstrated the potential for achieving a large el ectrostrictive response in these materials. Since the principal effect of t he radiation is network formation, alternative methods of achieving improve d electromechanical properties are available. In this letter, we use a two- solvent swelling technique to quantify the polymer-solvent interaction para meter for the copolymer networks. This enables determination of their cross link densities, along with a measure of the degree of degradation accompany ing radiolysis. Copolymer networks were then prepared chemically using orga nic peroxide. These networks were found to be similar to the radiation-cros slinked materials, both in the extent of degradation and with respect to th e Curie temperature and crystalline melting behavior. The latter are crucia l to the development of better electrostrictive properties. (C) 2001 Americ an Institute of Physics.