Quantitative analysis of polar crystalline fractions in poly(vinylidene fluoride) electrospun fibers and electrosprayed films
Quantitative analysis of polar crystalline fractions in poly(vinylidene fluoride) electrospun fibers and electrosprayed films
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DOI：
10.1016/j.polymer.2023.126140
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发表时间：
2023-07
期刊：
影响因子：
4.6
通讯作者：
Anuj Jayasekara;P. Cebe
中科院分区：
文献类型：
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作者：
Anuj Jayasekara;P. Cebe
我们已经使用了一种新的技术，傅立叶自去卷积（FSD）的红外光谱，量化的电活性（EA）在聚（偏二氟乙烯），PVDF的结晶相的相对分数。静电纺丝和静电喷雾是制备EA相的有效方法，EA相包括极性β（链构象，TTTT）和γ（TTTGTTTG '）晶相。在这项工作中，我们研究了静电纺丝纤维垫和电喷雾非纤维垫的PVDF从N，N-二甲基乙酰胺和丙酮的解决方案。广角X射线散射（WAXS）和傅里叶变换红外（FTIR）光谱表明，通过静电纺丝/电喷雾制备的样品仅含有极性晶体相，并且不存在非极性α相晶体。傅里叶自去卷积是一种用于综合窄化宽而复杂的红外吸收光谱的方法。在这里，我们演示了通过解析红外吸收光谱中840 cm− 1处的峰来确定β和γ相晶体的相对分数的技术。当结晶度的总体水平已知时，如在此通过X射线分析，则FSD允许确定极性β和γ相的绝对含量。比较广角X射线散射和FTIR/FSD的结果，我们发现，在静电纺丝和静电喷涂材料中，γ相占主导地位，相对γ/β比分别为55/45和81/19。
We have used a novel technique, Fourier self-deconvolution (FSD) of the infrared spectrum, to quantify the relative fractions of the electro-active (EA) crystal phases in poly(vinylidene fluoride), PVDF. Electrospinning and electrospraying are effective methods to obtain the EA phases which include the polar β (chain conformation, TTTT) and γ (TTTGTTTG’) crystallographic phases. In this work we studied electrospun fiber mats and electrosprayed non-fibrous mats of PVDF obtained from solutions of N,N-dimethylacetamide and acetone. Wide-angle X-ray scattering (WAXS) and Fourier-transform infrared (FTIR) spectra show that samples prepared by electrospinning/electrospraying contained only polar crystal phases, and no non-polar alpha phase crystals were present. Fourier Self Deconvolution is a method used to synthetically narrow broad and complex infrared absorbance spectra. Here we demonstrate this technique to determine the relative fractions of β- and γ-phase crystals by resolving the peak at 840 cm−1in the IR absorbance spectra. When the overall level of crystallinity is known, as it is here from X-ray analysis, then FSD allows determination of the absolute content of the polar β and γ phases. Comparing results from wide-angle X-ray scattering and FTIR/FSD, we show that γ-phase dominates over β-phase in both electrospun and electrosprayed materials, with relative γ to β ratios of 55/45 and 81/19, respectively.