Structural aspects of the high-temperature space charge relaxation in ferroelectric VDF/TFE 94/6 copolymer

Abstract

Structural changes in isotropic films of ferroelectric vinylidene fluoride (VDF)/tetrafluoroethylene (TFE) 94/6 copolymers in the metastable state have been studied on heating. The metastable state was ascribed to γ-crystals. The dielectric relaxation spectroscopy was employed to study space charge relaxation processes. Two relaxations were observed at high temperatures. One of them was attributed to relaxation of space charge accumulated on the Al electrode which may be partially blocked due to new functional groups formed in the polymer surface. Recrystallization of the film from the melt is accompanied by small α-crystals formation. This results in a decrease in activation energy of the space-charge relaxation process.

KEYWORDS:

• Ferroelectricity
• fluoropolymers
• crystallization
• dielectric properties