Quantification of the solvent evaporation rate during the production of three PVDF crystalline structure types by solvent casting

Abstract

In this study, we quantified the solvent evaporation rate in the production of three poly(vinylidene fluoride) (PVDF) crystalline structures using the solvent casting method, the first known report on such quantification. The evaporation conditions of drying temperature and pressure for the solvent species during solvent casting were varied. The results indicated that the crystalline structures of forms I, II and III of PVDF were obtained when the solvent evaporation rates were <0.0001, >0.2 and between 0.03 and 0.00058 g min−1, respectively. From the above quantitative analysis, it was established that the crystalline structure of PVDF from solvent casting is predominantly determined by the solvent evaporation rate. The solvent evaporation rate in the production of three types of poly(vinylidene fluoride) (PVDF) crystalline structures by using the solvent casting method was quantified. The PVDF crystalline structures were predominantly determined by solvent evaporation rate. PVDF (form I) was obtained when the solvent evaporation rate was <0.0001 g min−1, PVDF (form II) was obtained when the solvent evaporation rate >0.2 g min−1 and PVDF (form III) was obtained when the solvent evaporation rate was from 0.03 to 0.00058 g min−1.