Crystallization of Beta-phase Poly (vinylidene fluoride) films using dimethyl sulfoxide (DMSO) solvent and at suitable annealing condition

Abstract

In literature it has been reported that the gamma-phase PVDF film is formed from dimethyl sulfoxide (DMSO) solvents regardless of preparation temperature. In this report the crystallization of both alpha and gamma phase from DMSO solvent by varying preparation temperature has been described. This paper also describes the conversion of gamma-phase to beta- phase and alpha-phase at different annealing condition. When thin films were annealed at 90C for 5 hours, then maximum beta-phase content (greater than 95%) is present in PVDF thin film. The PVDF films completely converted to alpha-phase, when they were annealed at 160C for 5 hours. From (X-ray diffraction) XRD, Fourier Transform Infrared Spectrum (FTIR), (Differential thermal analysis) DTA and Raman studies, it is confirmed that the PVDF thin films, cast from DMSO solution and annealed at 90C for 5 hours, have maximum percentage of beta-phase(greater than 95%).