Investigation of relaxation process in poly(vinylidene fluoride–hexafluoropropylene) using dielectric relaxation spectroscopy

Abstract

Dielectric relaxation behavior of poly(vinylidene fluoride–hexafluoropropylene) [P(VDF–HFP)] is investigated on the basis of dielectric relaxation spectroscopy at 20–200 °C and 20–5 MHz after conversion to complex electric modulus formalism. It is found that imaginary modulus spectra exhibit asymmetry peak with peak-width much broader than that of the Debye peak. The peaks are skewed toward the high frequency sides due to the effect of the conductivity. The complex electric modulus data have been fitted using non-exponent Kohlrausch–Williams–Watts and Cole–Cole functions. The results show that the non-exponent parameter (β) and the shape parameter (α) are all lower than idealized Debye-type, indicating a wide relaxation distribution of P(VDF–HFP). Both the activation energies Ea from $${\text{M}}^{\prime \prime }$$ spectra and conductivity are all due to the contribution of dc and ac conductive relaxation process.