The self-assembly behavior of AB diblock copolymers under cylindrical confinement is investigated using the self-consistent field theory. We focus on the impact of the confinement on the order-order transitions of three-dimensional morphologies by constructing two types of phase diagrams with continuously varying block compositions. One type is with respect to the block composition and the immiscibility parameter for various pore sizes, in which the order-order transitions are shown to be strongly impacted by the pore curvature and thus largely different from the bulk ones. Note that the morphologies are categorized by the intrinsical geometry of their domains, i.e., that helical morphologies are regarded as one type of cylindrical phase. Another type of phase diagram is with respect to the block composition and the pore diameter, which exhibits a number of interesting order-order transitions, especially the transition sequence from a straight line of spheres, to one straight cylinder and stacked disks as the pore diameter increases. A critical point is observed at which the stability region of the straight cylinder vanishes and thereby the spheres transform into the stacked disks continuously. The mechanism of these phase transitions is rationalized in the context of the bulk factors as well as an additional factor, i.e., the competition between the spontaneous curvature of the copolymer and the imposed curvature by the nanopore.

中文翻译：

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圆柱约束下二嵌段共聚物熔体的有序转变

利用自洽场理论研究了AB二嵌段共聚物在圆柱约束下的自组装行为。通过构建具有连续变化的块组成的两种相图，我们专注于限制对三维形态的有序过渡的影响。关于嵌段组成和对于各种孔径的不溶混性参数，一种类型是，其中阶次跃迁显示出受孔隙曲率的强烈影响，因此与松散曲率有很大不同。请注意，形态是通过其域的固有几何来分类的，即，螺旋形态被视为圆柱相的一种类型。相图的另一种类型是关于嵌段的组成和孔径，随着孔径的增加，它表现出许多有趣的阶序转换，特别是从球的直线到一个直圆柱和叠置圆盘的转换顺序。观察到一个临界点，在该临界点上，直圆柱体的稳定区域消失了，从而使球体连续转变成堆叠的圆盘。这些相变的机理在体积因素以及附加因素的范围内是合理的，即共聚物的自发曲率和纳米孔施加的曲率之间的竞争。观察到一个临界点，在该临界点上，直圆柱体的稳定区域消失了，从而使球体连续转变成堆叠的圆盘。这些相变的机理在体积因素以及附加因素的范围内是合理的，即共聚物的自发曲率和纳米孔施加的曲率之间的竞争。观察到一个临界点，在该临界点上，直圆柱体的稳定区域消失了，从而使球体连续转变成堆叠的圆盘。这些相变的机理在体积因素以及附加因素的范围内是合理的，即共聚物的自发曲率和纳米孔施加的曲率之间的竞争。