Polarization of block textured films of ferroelectric copolymers of vinylidene fluoride with tetrafluoroethylene in an external field

Abstract

The polarization of oriented films of the ferroelectric copolymer of vinylidene fluoride and tetrafluoroethylene in a sinusoidal electric field is studied. In low fields, the copolymer behaves as a linear dielectric whose permittivity nonlinearly increases with the amplitude of the alternating field. This behavior is related to the preferential orientation of the dipole moment of the chain along the normal to the surface and to the monocrystal-structure formation. In higher fields, the hysteresis behaves formally coincidently with the behavior of an antiferroelectric. The important role of through stressed chains in the amorphous phase in the initiation of domains of a new direction in polar crystals is observed. Increased adsorption of water molecules on the surface of a polarized film is found and is attributed to the formation of the final density of the stable polarization charge on it.