Gelation-Induced Phase Separation of Poly(vinyl alcohol) in Mixed Solvents of Dimethyl Sulfoxide and Water

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• 作者：Nobuaki Takahashi ; Toshiji Kanaya ; Koji Nishida ; Keisuke Kaji
• 刊名：Macromolecules
• 出版年：2007
• 出版时间：November 27, 2007
• 年：2007
• 卷：40
• 期：24
• 页码：8750 - 8755
• 全文大小：135K
• 年卷期：v.40,no.24(November 27, 2007)
• ISSN：1520-5835

文摘

Time-resolved light-scattering measurements have been performed on poly(vinyl alcohol) (PVA)in mixed solvents of dimethyl sulfoxide (DMSO) and water with various mixing ratios after quenching from 100to 25 C to examine the physical gelation process. A broad scattering peak characteristic of phase separationappeared in the light-scattering profiles after a certain incubation time (t_m) and the peak position (Q_m) moved tohigher Q with annealing time. The results contradict the theoretical predictions and experimental observationsfor usual phase separation systems, suggesting the effects of gelation (or network formation) on the phase separation.The growth kinetics significantly depend on the mixing ratio of DMSO and water, showing that the solventquality is also a factor to affect the phase separation kinetics during the physical gelation process. The unusualphase separation kinetics is discussed in terms of gelation-induced phase separation.