Department of Macromolecular Science & Engineering, Case Western Reserve University, Cleveland Ohio 44106, United States.
LinQuest Corporation, Beavercreek, Ohio 45431, United States.
Langmuir. 2023 May 23;39(20):7154-7166. doi: 10.1021/acs.langmuir.3c00589. Epub 2023 May 8.
In recent decades, advances in the syntheses of mechanically interlocked macromolecules, such as catenanes, have led to much greater interest in the applications of these complexes, from molecular motors and actuators to nanoscale computational memory and nanoswitches. Much remains to be understood, however, regarding how catenated ring compounds behave as a result of the effects of different solvents as well as the effects of solvent/solvent interfaces. In this work, we have investigated, using molecular dynamics simulations, the effects of solvation of poly(ethylene oxide) chains of different topologies─linear, ring, and [2]catenane─in two solvents both considered favorable toward PEO (water, toluene) and at the water/toluene interface. Compared to ring and [2]catenane molecules, the linear PEO chain showed the largest increase in size at the water/toluene interface compared to bulk water or bulk toluene. Perhaps surprisingly, observations indicate that the tendency of all three topologies to extend at the water/toluene interface may have more to do with screening the interaction between the two solvents than with optimizing specific solvent-polymer contacts.
近几十年来，机械互锁大分子的合成技术（如索烃）取得了进展，这使得人们对这些配合物的应用产生了更大的兴趣，从分子马达和执行器到纳米级计算存储器和纳米开关。然而，对于交联环化合物如何由于不同溶剂的影响以及溶剂/溶剂界面的影响而表现出不同的行为，仍有许多需要了解。在这项工作中，我们使用分子动力学模拟研究了不同拓扑结构的聚（氧化乙烯）链（线性、环和[2]索烃）在两种被认为有利于聚氧化乙烯的溶剂（水和甲苯）以及在水/甲苯界面中的溶剂化效应。与环和[2]索烃分子相比，线性 PEO 链在水/甲苯界面处与本体水或本体甲苯相比，尺寸增加最大。也许令人惊讶的是，观察结果表明，所有三种拓扑结构在水/甲苯界面处伸展的趋势可能更多地与屏蔽两种溶剂之间的相互作用有关，而不是与优化特定溶剂-聚合物接触有关。
