溶剂尺寸对ABA两亲性三嵌段共聚物在选择性溶剂中自组装行为影响的Monte Carlo模拟

摘要

The effect of solvent molecular size on the self-assembly of ABA amphiphilic triblock copolymer in a selective solvent was studied by means of Monte Carlo simulation. The simulative results show that the solvent molecular size is one of the key factors that determine the morphologies of the copolymer aggregates. The morphologies formed by ABA amphiphilic triblock copolymers changed from spheres to rod and then to vesicle by increasing the solvent molecular size. By analyzing the variations of the contact number between monomers, it was found that the morphological transition was induced by the decreasing of the solvent solubility when increasing the solvent molecular size. Moreover, the phase diagrams in terms of the core-solvent interaction and the solvent molecular size as well as the corona-solvent interaction and the solvent molecular size were given, respectively. The results revealed that increasing solvent molecular size, core-solvent interaction and decreasing corona-solvent interaction had an equivalent effect on the self-assembled structure for the ABA amphiphilic triblock copolymers.%采用Monte Carlo模拟方法研究了溶剂尺寸对ABA两亲性三嵌段共聚物在选择性溶剂中自组装行为的影响.模拟结果表明,溶剂尺寸是决定共聚物聚集形态的重要因素之一.随着溶剂尺寸的增大,嵌段共聚物自组装所形成的胶束可以发生从球状到棒状再到囊泡状的转变.通过对各组分相互作用的对数随溶剂尺寸变化曲线的分析发现,增大溶剂尺寸会使溶剂的溶解性变差,由此引发体系中的一系列形态转变.此外,通过对体系自组装形貌结构相图的分析发现,增大溶剂尺寸或增加疏水作用与减小亲水作用对于自组装形态的改变具有同等效果.