水蒸气诱导聚电解质刷的构象转变 |
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引用本文: | 赵新军.水蒸气诱导聚电解质刷的构象转变[J].原子与分子物理学报,2018,35(6). |
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作者姓名: | 赵新军 |
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作者单位: | 伊犁师范学院物理学院 |
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摘 要: | 我们把 Flory−Huggins 模型(association models)推广应用暴露于水蒸气中的聚电解质刷体系,考虑聚电解质-水氢键(P-W氢键)与水-水氢键(W-W氢键)、形成氢键与聚电解质链构象的耦合特性,研究水蒸气诱导的聚电解质刷构象转变的机理.研究发现,当 P-W 氢键效应起主导作用时,随着水蒸气浓度的增加,聚电解质刷会单调溶胀;P-W 和 W-W 两种氢键效应,则会导致随着水蒸气浓度的增加,聚电解质刷的构象首先塌缩,然后开始溶胀的反常转变行为。基于本文的分析,可以预言,由于 P-W 氢键效应,聚电解质刷可以吸附水蒸气,吸附能力随聚电解质链长的增加而增强;当聚电解质链接枝密度足够高时,由于 P-W 和 W-W 两种氢键效应,增加体系中的水蒸气,会在聚电解质刷体系中形成由 P-W 氢键和 W-W 氢键交错链接的三维网络状凝胶结构。
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关 键 词: | 水蒸气 聚电解质刷 氢键 构象转变 |
收稿时间: | 2016/5/20 0:00:00 |
修稿时间: | 2016/6/26 0:00:00 |
Switching of polyelectrolyte brushes by water vapor |
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Abstract: | We presented a theory to study switching of polyelectrolyte brushes by water vapor. Our theory model include the consideration of polyelectrolyte-water(P-W) and water-water(W-W) molecules hydrogen bonds. We found that P-W hydrogen bonds become a key element in inducing swelling of polyelectrolyte brushes. Our results also indicate that the combination of P-W and W-W hydrogen bonds can result in a nonmonotonic dependence of a brush height on water vapor concentration: while the brush initially shrinks with increasing humidity until it reaches a minimum, and then it stretches with increasing humidity. Based on our theoretical model, we can predict, because of P-W of hydrogen bonds, polyelectrolyte brushes can adsorb water vapor,and adsorption capacity also increases with chain-length and brush-height;P-W and W-W hydrogen bonds hybridization will lead to a hydrogen-bond network formation of 3D polyelectrolyte brushes. |
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Keywords: | Water vapor Polyelectrolyte brushes Hydrogen bonding Switching |
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