Tunable Helical Structures Formed by ABC Triblock Copolymers under Cylindrical Confinement
Tunable Helical Structures Formed by ABC Triblock Copolymers under Cylindrical Confinement
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圆柱约束下ABC三嵌段共聚物形成的可调螺旋结构
DOI：
10.1039/c9cp04978a
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Xinping Wang
中科院分区：
文献类型：
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作者：
Meijiao Liu;Ka Chen;Weihua Li;Xinping Wang
嵌段共聚物被限制在纳米孔中，为螺旋结构的形成提供了独特的非手性体系。AB嵌段共聚物具有稳定的单螺旋和双螺旋结构。为了获得更多不同的螺旋结构，我们用线性ABC三嵌段共聚物代替AB二嵌段共聚物。我们推测在纳米孔内形成核-壳超结构，其由A-壳内的B-螺旋包裹的C-核圆柱体组成。因此，将孔表面设置为对大多数A嵌段最有吸引力，并且选择一组典型的相互作用参数为XACN = XABN = XBCN = 80以产生受抑界面。此外，B块的体积分数固定为fB = 0.1，以形成螺旋柱。通过自洽场理论预测了具有范围从1到5的链的螺旋结构的数量，并且在一般情况下，链的数量随着给定纳米孔中C-块fC的体积分数的增加而减少。更令人惊讶的是，在受限系统中的螺旋股的变化有相反的趋势，在体中，这主要是由于圆柱形的限制的外部A-层和内部B/C-超畴之间的曲率的变化的约束。我们的工作展示了一种简单的方法来制造不同的螺旋超结构。
Block copolymers confined in nanopores provide unique achiral systems for the formation of helical structures. With AB diblock copolymers, stable single and double helical structures are observed. Aiming to obtain more different helical structures, we replace the AB diblock copolymer with linear ABC triblock copolymers. We speculate that a core–shell superstructure is formed within the nanopore, which is composed of a C-core cylinder wrapped by B-helices within the A-shell. Accordingly, the pore surface is set to be most attractive to the majority A-block and a typical set of interaction parameters is chosen as χACN ≪ χABN = χBCN = 80 to generate the frustrated interfaces. Furthermore, the volume fraction of B-block is fixed as fB = 0.1 to form helical cylinders. A number of helical structures with strands ranging from 1 to 5 are predicted by self-consistent field theory, and in general, the number of strands decreases as the volume fraction of C-block fC increases in a given nanopore. More surprisingly, the variation of helical strand in the confined system has an opposite trend to that in the bulk, which mainly results from the constraint of the cylindrical confinement on the change of the curvature between the outer A-layer and the inner B/C-superdomain. Our work demonstrates a facile way to fabricate different helical superstructures.