采用Monte Carlo模拟方法研究了ABA两亲性三嵌段共聚物在两种选择性溶剂中的自组装行为.模拟结果表明,在保证溶剂总浓度一定的情况下,改变两种选择性溶剂的体积比对于ABA两亲性嵌段共聚物自组装所形成的胶束形貌结构有很大影响.随着双选择性溶剂体积比的改变,体系中胶束形貌结构将会发生由囊泡到层状,再到环状、棒状直至球状的一系列转变.通过与ABA两亲性嵌段共聚物在单一选择性溶剂中的自组装行为进行比较发现:改变双选择性溶剂的体积比对于体系胶束形貌结构的影响与在单一选择性溶剂中改变疏水作用具有等同效果.此外,针对体系中囊泡以及环状胶束自组装动力学过程的研究发现:囊泡状胶束是由片层状胶束弯曲闭合形成,而环状胶束则是由片层状胶束从中间塌陷形成.
The effect of binary block-selective solvents on the self-assembly of ABA amphiphilic triblock copolymer in dilute solution was studied by means of Monte Carlo study.The simulative results showed that the proportion of the binary block-selective solvents is one of the key factors that determines the morpholo-gies of the copolymer aggregates.The morphologies formed by ABA amphiphilic triblock copolymers changed from vesicle to lamella,ring,rod,and then to spheres by changing the proportion of binary solvent mixtures.The results revealed that changing the proportion of binary solvent mixtures and adjusting core-solvent interaction of single solvent had an equivalent effect on the self-assembled structure for the ABA amphiphilic triblock copolymers.Moreover,the dynamical pathways leading to ring and vesicle are analyzed in detail.It was found that the oblate membranes closed up to form vesicles,while the oblate membranes dissolved a hole to form ring.