Experimental and DFT investigation of surface degradation of polyvinylidene fluoride membrane in alkaline solution

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• 作者：Xiaodan Zhao^a ; Laizhou Song ; ^a ; ^{songlz@ysu.edu.cn"" rel=""nofollow} ; Jie Fu^a ; Pei Tang^a ; Feng Liu^a
• 关键词：Polyvinylidene fluoride membrane ; Alkaline treatment ; Surface degradation ; Density functional theory calculations
• 刊名：Surface Science
• 出版年：2011
• 出版时间：June 2011
• 年：2011
• 卷：605
• 期：11-12
• 页码：1005-1015
• 全文大小：1692 K

文摘

The degradation processes of polyvinylidene fluoride (PVDF) membranes in alkaline solutions were studied using FTIR, FT-Raman, XPS and density functional theory (DFT) simulations. The activation energies for the degradation paths were calculated by LST/QST search methods. The corresponding Gibbs free energies were calculated using a continuum solvation model. The analysis of the spectra indicates the presence of C=C bonds, hydroxyl and carbonyl groups on PVDF membranes. It can be inferred, from DFT calculations, that defluorination is the energetically favorable path, followed by the formation of C=C bonds. The subsequent hydroxylation and carbonyl formation experience higher activation barriers than the formation of C=C bonds. The results indicate that the theoretical calculations are in accordance with the experimental data.