Ferroelectric Transition in 70/30 VF2 /TrFE Copolymer Studied by Deuteron nmr

Abstract

Deuteron pulse nuclear magnetic resonance (NMR) spectra and spin-spin (T2) and spin-lattice (T1) relaxation times were measured between 20 and 140°C for a 70/30 mol% random copolymer of deuterated vinylidene fluoride (VF2) and normal trifluoroethylene (TrFE). These “powder” spectra were simulated by the Vold procedure and were dePaked to aid in studying the molecular motions. The spectra show that the ferroelectric (FE) transition occurs between 40 and 140°C with large thermal hysteresis. The dePaked spectra at 140°C are consistent with a dynamically disordered 3/1 helical structure.