Crystallization and gelation of poly(vinylidene fluoride) in organic solvents

Abstract

Poly(vinylidene fluoride) (PVdF) converts easily to thermally reversible gel at room temperature in aliphatic ketones or cyclic ketones such as 3-pentanone, 3-hexanone, cyclohexanone, and -butyrolactone, etc. Gelation of PVdF in these ketones took place through crystallization of polymers from solution. The crystallization process was investigated in detail by Fourier transform infrared (FTIR) measurements. The FTIR spectra were recorded continuously at room temperature until the solution converted to gel. It was suggested from spectral data that polymer chains packed together (i.e., crystallization took place) into the TTTGTTTG¯ conformation in the case of PVdF/γ-butyrolactone solution, followed immediately by gelation. On the other hand, crystallization occurred into the TGTG¯ conformation in the case of other ketones and gelation immediately took place. Melting temperatures of PVdF gels thus prepared from these solvents were measured. showed a solvent dependence. © 1997 John Wiley & Sons, Inc. J Appl Polm Sci 65:1517–1524, 1997