Effect of electron irradiation on the ferroelectric transition of P (VDF-TrFE) copolymers

Abstract

The dielectric constant of random P (VDF-TrFE) (70-30) copolymers has been measured as a function of the temperature and frequency for various doses of 100 keV and 3 MeV electron irradiation. The ferroelectric transition temperature is found to decrease as a function of the irradiation dose whereas the width of the temperature hysteresis is reduced. X-rays measurements revealed that a major consequence of the irradiation is to extend the temperature range of the paraelectric phase. For doses above ∼ 50 Mrad (at 100 keV) no ferroelectric phase at all is observed. Consistent with the frequency dependance of dielectric constant measurement, for this dose range, we suggest that the crystalline phase undergoes a glassy-like transition, leading to the inhibition of dipolar ordering.