writer：Jie Cui, Yuanyuan Han, Wei Jiang
keywords：不对称囊泡, Monte Carlo模拟, 嵌段共聚物混合物, 亲水链段分布, 界面能
source：期刊
specific source：Langmuir, 2014, 30(30), 9219-9227
Issue time：2014年

摘要：采用Monte Carlo模拟研究了AB/CB两嵌段共聚物混合物在A和C嵌段选择性溶剂中形成的不对称囊泡。系统考察了两嵌段共聚物的混合比例、溶液pH和亲水链长对不对称囊泡表面亲水嵌段分布的影响。结果表明，由AB/CB共聚物混合物可获得内外表面由不同亲水嵌段构成的不对称囊泡；形成ABC型还是CBA型三层不对称囊泡取决于混合物组成、亲水链长和溶液pH。带同种电荷（由溶液pH诱导）、链较长或混合物中含量较低的亲水嵌段更倾向于分布在囊泡外表面；当C嵌段带电时，可通过调节混合物组成实现ABC向CBA三层不对称囊泡的转变。界面能密度分析表明，当亲水链长相等时，内外界面能的差异是决定不对称囊泡结构的主要因素，不同亲水嵌段在囊泡上的分布倾向于获得最大的内外界面能差；当亲水链长不同时，链构象熵成为决定亲水嵌段分布的主要驱动力。

Abstract：Asymmetric vesicles constructed from AB/CB diblock copolymer mixture in a selective solvent for A and C blocks are studied using Monte Carlo simulation. The effects of the mixed ratio of the two diblock copolymers, the solution pH, and the hydrophilic chain length on the distributions of hydrophilic blocks on the surfaces of asymmetric vesicles are studied systematically. The simulation results show that asymmetric vesicles, in which the inner and outer surfaces are constructed from different hydrophilic blocks, can be obtained from the AB/CB diblock copolymer mixture. The formation of ABC or CBA three-layer asymmetric vesicles depends on the composition of the mixture, the chain length of the hydrophilic block, and the solution pH. The hydrophilic block with the same charge (induced by the solution pH), or longer chain length, or lower content in the mixture is more likely to distribute on the outer surface of the vesicle. When the hydrophilic chain lengths are equal, the difference between the outer and inner interfacial energies is the main factor that determines the asymmetric vesicle structures; when the hydrophilic chain lengths are different, the chain conformational entropy becomes the main driving force for determining the distribution of hydrophilic blocks on asymmetric vesicles.

论文链接：https://doi.org/10.1021/la501674a