The microdomain structures and liquid crystal (LC) orientations of ABA triblock copolymers comprising poly(styrene) (PS) A blocks and a main-chain LC polyester B block were examined via small-angle X-ray scattering and electron microscopy in the form of fibrous samples. The LC polyester blocks were segregated from the PS blocks to form a nematic LC in the lamellar microdomains of the copolymers, with the PS volume fraction (φ) ranging from 13 to 38%. As φ decreased, the nematic director was always positioned along the fiber axis, but the microdomain lamellae changed their direction from parallel to perpendicular with respect to the fiber axis and began to adopt a zigzag configuration. These lamellar orientations were attributed to the main-chain nematic LC segments lying along the microdomain interface but extending perpendicularly to the interface as the occupying interface area was reduced. The lamellar microdomains parallel to the nematic director increased the LC and PS lamellar thicknesses reversibly by 48 and 16%, respectively, at the same time as the isotropization of the nematic LC. Such changes in lamellar thickness suggest that both the PS and LC segments were elongated along the direction of the LC orientation.Lamellar microdomain and liquid crystal (LC) orientations in a fibrous sample were investigated for a series of ABA triblock copolymers comprising poly(styrene) (PS) A blocks and a main-chain nematic LC polyester B block. As the PS volume fraction decreased from 38 to 13%, the lamellae changed their direction from parallel to perpendicular with respect to the fiber axis and began to adopt a zigzag configuration, although the LC mesogens always lay along the fiber axis. At the microdomain interface, the LC mesogens exhibited an anchoring transition from planar to homeotropic.

中文翻译：

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对于嵌段共聚物的主链向列聚酯链段观察到的液晶锚定在微域界面的转变

通过小角度 X 射线散射和电子显微镜以以下形式检查包含聚（苯乙烯）（PS）A 嵌段和主链 LC 聚酯 B 嵌段的 ABA 三嵌段共聚物的微畴结构和液晶（LC）取向纤维样品。LC 聚酯嵌段与 PS 嵌段分离，在共聚物的层状微畴中形成向列型 LC，PS 的体积分数 (φ) 为 13% 至 38%。随着 φ 的减小，向列指向矢始终沿纤维轴定位，但微畴薄片的方向从与纤维轴平行变为垂直，并开始采用锯齿形结构。这些层状取向归因于主链向列型 LC 链段位于微域界面，但随着占据界面面积的减少而垂直于界面延伸。与向列导向器平行的层状微畴使 LC 和 PS 层状厚度分别可逆地增加了 48% 和 16%，同时向列 LC 各向同性化。层状厚度的这种变化表明 PS 和 LC 链段都沿 LC 取向的方向拉长。 研究了纤维样品中的一系列 ABA 三嵌段共聚物的层状微畴和液晶 (LC) 取向，其中包括聚苯乙烯(PS) A 嵌段和主链向列型 LC 聚酯 B 嵌段。随着 PS 体积分数从 38% 下降到 13%，薄片相对于纤维轴的方向从平行变为垂直，并开始采用锯齿形结构，尽管液晶介晶始终沿纤维轴排列。在微域界面处，LC 介晶表现出从平面到垂直的锚定转变。