Determination of the crystalline phases of poly(vinylidene fluoride) under different preparation conditions using differential scanning calorimetry and infrared spectroscopy

摘要: A method with good precision has been developed to quantitatively measure the degree of α-, β-, and γ crystallinity in poly(vinylidene fluoride) (PVDF) by means infrared spectroscopy. The phase composition solution-deposited PVDF films was found be strongly influenced presence hydrophilic residues on silicon substrate, relative humidity present at film deposition, spatial position thermal treatment deposited film. Films produced pristine surfaces gave predominantly α-phase PVDF, but when a layer polar solvent (acetone or methanol) remained surface, were phase. Higher promoted higher fraction films. Solution-cast had highly variable across whereas spin-cast uniform. High-temperature annealing normally converts polymer phase, while still attached substrate inhibited this transformation. Low-temperature freestanding led previously unreported event DSC, premelting process that is kinetic event, assigned crystalline relaxation. Higher-temperature double endotherm, melting different-sized domains. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1093–1100,