Meng Linghao, Wei Rong, Xie Zhaoxin, Zhang Di, Wan Xiaohan, Han Han, Shi Wenjing, Zhu Ziqi, Xiao Xiao, Gao Yi Qin, Zhao Dahui
Beijing National Laboratory for Molecular Sciences, Centre for the Soft Matter Science and Engineering, The Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry, Peking University Beijing 100871 China
Chem Sci. 2025 Jul 23. doi: 10.1039/d5sc03588k.
Owing to their green nature, good miscibility and tunable polarity, alcohols are widely used as popular co-solvents of water in supramolecular assembly. Intriguingly, the solvation properties of water/alcohol mixtures often show a complex dependence on the composition. Herein, the unusual solvation effects of water and alcohol mixtures are elucidated by examining the aggregation motif changes of amphiphilic polycycles bearing more polar side chains. While the molecule assembles into long fibrous J-aggregates in pure water and alcohols, H-aggregates of smaller sizes appear in water-alcohol mixtures. Similar dissociation is found to occur in different low-carbon alcohol-water systems, but H/J switching takes place at different volume ratios, depending on the alcohol structure. It is thus speculated that the aggregate dissociations reflect an enhanced solubilizing ability of the mixed solvents, which is assumed to be related to the microscopic structures of the water-alcohol binary systems. That is, the highly structured networks formed by mixed water and alcohols possess enhanced solvating capacity for the amphiphilic molecules, and alcohols having longer alkyl groups and forming larger structured hydration shells in water disrupt the aggregation more effectively. Molecular dynamics simulations have provided supportive evidence for the special solubilizing properties of mixed water and alcohols.
由于具有绿色环保、良好的混溶性和可调节的极性，醇类作为超分子组装中常用的水的共溶剂被广泛使用。有趣的是，水/醇混合物的溶剂化性质通常对组成表现出复杂的依赖性。在此，通过研究带有更多极性侧链的两亲多环化合物的聚集基序变化，阐明了水和醇混合物不同寻常的溶剂化效应。虽然该分子在纯水和醇中组装成长纤维状的J-聚集体，但在水-醇混合物中会出现较小尺寸的H-聚集体。发现在不同的低碳醇-水体系中会发生类似的解离，但H/J转换发生在不同的体积比，这取决于醇的结构。因此推测，聚集体的解离反映了混合溶剂溶解能力的增强，这被认为与水-醇二元体系的微观结构有关。也就是说，由水和醇混合形成的高度结构化网络对两亲分子具有增强的溶剂化能力，并且在水中具有更长烷基并形成更大结构化水合壳的醇更有效地破坏聚集。分子动力学模拟为水和醇混合物的特殊溶解性质提供了支持性证据。
