化对水溶性聚合物的溶解自由能的贡献
Jennifer A Clark1, Jack F Douglas1
1Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland20899, United States.
The journal of physical chemistry. B
|June 3, 2025
概括
了解聚合物水化是自组装的关键. 这项研究量化了动态水化层 (DHL) 对聚合物溶解自由能量的性贡献,揭示了聚合物接口上的离子特异性影响.
科学领域:
- 物理化学 物理化学
- 聚合物科学 聚合物科学
- 计算化学的计算化学
背景情况:
- 溶解自由能量对于理解聚合物在溶液中的行为至关重要.
- 聚合物周围的动态水化层 (DHL) 显著影响溶解热力学.
- 来自DHL的量子化贡献对于准确的溶解模型至关重要.
研究的目的:
- 为了研究动态水化层 (DHL) 对水溶性聚合物的溶解自由能量的热贡献.
- 使用棒状聚合物模型,将聚合物水化效应与形状变化隔离.
- 分析特定离子对聚合物溶解和DHL结构的影响.
主要方法:
- 对杆状聚合物进行模拟的溶解自由能量计算.
- 使用德拜-沃勒参数 (u2) 量化动态水化层 (DHL).
- 分析基克伍德-巴夫积分来评估离子特异效应和溶剂结构.
主要成果:
- 从聚合物水化中确定了显著的热贡献,与Kirkwood-Buff整数的变化相关.
- 在DHL中的水流动性取决于聚合物-溶剂相互作用,但与散装相比没有额外的特定离子效应.
- 杂热离子 (CsCl) 在聚合物附近显示过度密度,而宇宙热离子 (NaCl) 显示消耗.
结论:
- 聚合物水化,特别是DHL,在整体溶解自由能量中起着重要作用.
- 特定的离子效应会影响聚合物界面上的离子分布,但不会影响DHL的移动性或范围.
- 这些发现对于理解聚合物溶液中分子自我组装和相位分离的热力学至关重要.
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