Peculiarities of high-temperature dielectric relaxation in vinylidene fluoride - hexafluoropropylene copolymers

A method of broad-band dielectric relaxation spectroscopy (10(-1)-10(7) Hz) has been used to study the mechanisms of high-temperature relaxation, related to space charge and electrode phenomena, in extruded films of vinylidene fluoride - hexafluoropropylene copolymer. The analysis of dielectric data on films of different thickness showed qualitative agreement with Iwamoto theory. Quantitative correlation of temperature dependencies of the relaxation times with conclusions of this theory assumes that not only the film thickness, but also the diffusion coefficient must be taken into account. It was found that mobility characteristics of the space charge are dependent upon the electrode material. (c) 2010 Elsevier B.V. All rights reserved.