Liquid crystals under confinement in submicrometer capsules
Liquid crystals under confinement in submicrometer capsules
复制标题
亚微米胶囊中的液晶
DOI：
10.1021/acs.langmuir.8b01056
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发表时间：
2018
期刊：
影响因子：
3.9
通讯作者：
Ivan I Smalyukh
中科院分区：
文献类型：
--
作者：
Haiyan Peng;Wenhong Jiang;Qingkun Liu;Guannan Chen;Mingli Ni;Fuxin Liang;Yonggui Liao;Xiaolin Xie;Ivan I Smalyukh
液晶在受限条件下的有序和相变行为引起了广泛的关注，并得到了广泛的应用。然而，亚微米微胶囊中LC的有序和相变行为很少被研究，主要是由于缺乏适当的胶囊化和可视化方法。本研究利用乳化界面溶胶-凝胶反应制备了尺寸小至100 nm的亚微米级LC胶囊。研究了微胶囊在亚微米约束条件下的行为，并对微胶囊壳表面的尺寸和化学成分进行了可控调节。在强约束条件下，由于lc的表面有序，使得亚微米微胶囊中lc的相变温度与体lc的相变温度发生了变化，从而导致拓扑缺陷的形成和序参量的改变。利用非线性光学成像技术，我们研究了由于表面边界条件和LC弹性之间的竞争而产生的LC的指向场结构。结果表明，在不同的约束条件下，纳米尺度的包封可以显著影响引子的结构构型和lc的相变。
Liquid crystal (LC) ordering and phase transition behavior under confined conditions have attracted extensive attention and enabled many applications. However, the ordering and phase transition behavior of LCs in submicrometer capsules have seldom been studied, primarily due to the lack of proper capsulizing and visualization approaches to such small LC microcapsules. Herein, we achieve submicrometer LC capsules with the sizes down to 100 nm by using emulsion-based interfacial sol–gel reaction. The behavior of LCs under the submicrometer confinement conditions is investigated while the sizes and chemical composition of the microcapsule shell surface are tuned in a controllable way. The phase transition temperatures of LCs in the submicrometer capsules shift from those of bulk LCs due to the surface-induced ordering of LCs under the strong confinement conditions, which causes formation of topological defects and alters the order parameter. Using nonlinear optical imaging technology, we explore the structures of director field of LCs that arise as a result of the competition between the surface boundary conditions and LC elasticity. The results show that the nanoscale encapsulation can significantly influence the structural configurations of the director and phase transitions of LCs under various confinement conditions.