The Role of Solution Phase Water on the Deposition of Thin Films of Poly(vinylidene fluoride)

Abstract

Thin films of PVDF were deposited from a variety of solution conditions and examined by IR spectroscopy and scanning electron microscopy. Methods to rapidly assess the film thickness and the phase composition of PVDF films have been developed. In particular, the formation of the ferroelectric phase can be controlled by the composition of the solvent, notably the water content. Using a hydrated salt in the casting solvent reproducibly formed films with high phase content. However, the water also induces increased surface roughness in the deposited films. The nature of the PVDF films also is influenced by the kinetics of the evaporation process, and this was followed by IR spectroscopy. The rate constants depend on both the film thickness and the gas-phase humidity, indicating that solvent diffusion is an important contributor to both the bulk phase composition and the surface structure of the polymer films.

Spin cast ferroelectric beta poly(vinylidene fluoride) thin films via rapid thermal annealing

“…We chose DMF as a reasonable starting point for fabricating thin films with ␤ crystals because polar solvents such as DMF and dimethyl sulfoxide usually give rise to thin films with dominantly ␥ crystals. 9 The humidity enhanced the amount of ␤ crystals, consistent with the results by others, 9 but significantly deteriorated the film surface, inappropriate for thin film device. In order to minimize the effect of water vapor, the chamber was purged with N 2 gas during the film formation.…”

Effect of solution-blended poly(styrene-co-acrylonitrile) copolymer on crystallization of poly(vinylidene fluoride)

“…The stronger dipolar interactions between PVDF and DMF might induce the trans conformation packing of CH 2 -CF 2 dipoles of β-phase [27]. Mixtures with lower dipole moment resulted in the nonpolar α-phase [28]. Figure 3 is a schematic presentation of PVDF/PAN/DMF phase diagram which demonstrates that PAN and PVDF belong to partially miscible systems by adding small amount of PVDF or PAN into the solution [29].…”

“…The nonpolar styrene segment in SAN copolymer further reduces the homogenous and partially miscible zones. However, this nonpolar styrene also reduces the number of dipoles in the mixtures which favors the formation the nonpolar α-phase [28]. As used SAN has 33 wt% AN, in the sample of 10 wt% SAN blended PVDF mixture, there is 3.3 wt% AN which might have good miscibility with PVDF.…”

Preparation and Characterization of PVDF/PMMA/Graphene Polymer Blend Nanocomposites by Using ATR-FTIR Technique

“…It should be pointed that since the -and -phase are similar to each other in short segmental conformations the identification of crystal phase between and in FTIR spectrum is still in dispute. On the basis of the data from literature the absorption band at 763 cm -1 is related to In-plane bending or rocking vibration in phase (N. Betz, 1994& S. Lanceros-Me ndez, 2001, the band at 840 cm -1 stretching in or phase (G. Chi Chen, 1994 , V. Bharti, 1997, B. Mattsson, 1999& M. Benz, 2002, the band at 1173 cm −1 is associated to the symmetrical stretching of -CF 2 group (M. Rajendran, 2010). The band at 1234 cm −1 is related to the phase and 1453 cm -1 is assigned to in-plane bending or scissoring of CH 2 group (M. Rajendran, 2010& Garton, 1992).…”