writer：Yingying Wang, Yuanyuan Han, Jie Cui, Wei Jiang, Yingchun Sun
keywords：Monte Carlo模拟, 简并行为, AB两嵌段共聚物, 纳米粒子, 圆柱受限
source：期刊
specific source：Langmuir, 2016, 32(33), 8484-8493
Issue time：2016年

摘要：简并行为，即在相同受限条件下给定嵌段共聚物形成不同自组装结构，普遍存在于各种受限体系中，理解简并行为对于精确控制受限自组装体系的结构至关重要。本文采用Monte Carlo模拟研究了AB两嵌段共聚物/纳米粒子（NP）混合物在圆柱孔中的简并行为。研究发现，该混合物的简并行为依赖于NP的引入。在不同孔径下，当NP含量为零时可获得四种典型简并结构，即单螺旋、双螺旋、平行圆柱和堆叠环状结构；但随着NP含量增加，简并结构数量减少，高NP含量时只能获得块状结构。此外，NP含量增加时单螺旋的形成概率降低，而双螺旋的形成概率升高。对体系相互作用焓密度和链构象的分析表明，熵在简并结构形成中起重要作用。该研究为受限条件下BCP/NP混合物的简并行为提供了新的认识，可为后续实验提供理论参考。

Abstract：Degenerate behavior (i.e., forming different self-assembled structures for a given block copolymer (BCP) under the same confinement) commonly exists in various confined systems. Understanding degenerate behavior is crucial for precise control over the structures formed by self-assembly systems under confinement. In this study, the degenerate behavior of a self-assembled AB diblock copolymer/nanoparticle (NP) mixture in a cylindrical pore is studied using Monte Carlo simulation. We find that the degenerate behavior of such a mixture depends on the introduction of the NP. Under different pore sizes, four typical degenerate structures (i.e., single helices, double helices, parallel cylinders, and stacked toroids) can be obtained if the NP content is zero. However, when the NP content in the mixture is increased, the number of degenerate structures decreases, and only blocky structures can be obtained in the case of high NP content. Moreover, the probability of forming S-helices decreases, whereas the probability of forming D-helices increases with increase in the NP content. Analysis of the interactive enthalpy densities and the chain conformation indicates that entropy plays an important role in the degenerate structure formation.

论文链接：https://doi.org/10.1021/acs.langmuir.6b01090