Effects of Thickness on Ferroelectricity in Vinylidene Fluoride and Trifluoroethylene Copolymers

摘要: The effects of thickness on ferroelectricity in vinylidene fluoride and trifluoroethylene copolymers have been investigated mainly through switching measurements. Switching phenomena as a result ultimately 180° rotations individual chain molecules around their axes were observed the copolymer films with thicknesses range 0.03-1 µ m. With decreasing film thickness, times increase, curve becomes broad permittivity at Curie point decreases. However, amount reversed polarization is nearly independent thickness. These results are generally reproducible if we assume surface layer less than 0.01 m, low permittivity, absence ferroelectric even presence an applied electric field.