Electron irradiation effects in ferroelectric vinylidene fluoride trifluoro-ethylene copolymers

Abstract

Abstract We have studied the effect of 100 keV electron irradiation on the physical properties of the ferroelectric vinylidene fluoride trifluoro-ethylene (VF2-F3E) random copolymer. In situ dielectric measurements (in the range 100 Hz - 100 kHz) have been performed as a function of the irradiation dose for two different comonomer ratios, VF2/F3E, of respectively. 70/30 and 60/40 mol %. In both cases, a decrease in the Curie temperature, Tc, and in the maximum of the dielectric constant ϵ max, have been observed. Differential scanning calorimetry experiments have revealed that the melting temperature. Tm, was lowered by irradiation. In addition, the enthalpy changes associated to the para-ferroelectric transition and to the melting were continuously reduced for increasing irradiation doses. All these results are consistent with a reduction in the degree of crystallinity of the crystalline phase and a reduction of the crystallites size which are induced by the electron irradiation.