Nanosegregated Chiral Materials with Self-Assembled Hierarchical Mesophases: Effect of Thermotropic and Photoinduced Polymorphism in Rodlike Molecules
Nanosegregated Chiral Materials with Self-Assembled Hierarchical Mesophases: Effect of Thermotropic and Photoinduced Polymorphism in Rodlike Molecules
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DOI：
10.1002/chem.201703778
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发表时间：
2017-12-14
影响因子：
4.3
通讯作者：
Choi, Suk-Won
中科院分区：
文献类型：
--
作者：
Jeon, Sung-Wook;Kim, Dae-Yoon;Choi, Suk-Won
观察到非手性弯核（BC）和非手性棒状介晶的二元混合物中的超分子手性。在二元系统中确定了三种不同的纳米偏析中间相，并且在棒状介晶的相变温度附近检测到圆二色性（CD）的有意义的变化。二元系统中最高的 CD 强度出现在纳米偏析中间相中，其中 BC 介晶处于螺旋纳米丝 (HNF) 相，棒状介晶处于近晶 A 相。二元混合物中的超分子手性归因于自组装的分层手性超结构。根据实验结果，提出了嵌入 HNF 网络中的棒状分子的手性超结构的合理方案。此外，包含BC和掺杂光响应化合物的棒状分子的系统表现出显着的CD强度光切换。根据BC分子HNF中嵌入分子的等温光诱导相变，可以动态和可逆地调节观察到的CD强度。这种具有易于控制功能的材料在材料科学领域引起了极大的兴趣。
Supramolecular chirality in a binary mixture of achiral bent-core (BC) and achiral rodlike mesogens was observed. Three different nanosegregated mesophases were determined in the binary system, and meaningful changes in circular dichroism (CD) were detected near the phase-transition temperatures of the rodlike mesogens. The highest CD intensity in the binary system was noted in the nanosegregated mesophase, in which the BC mesogens were in the helical nanofilament (HNF) phase and the rodlike mesogens were in the smectic A phase. The supramolecular chirality in the binary mixture was attributed to the self-assembled hierarchical chiral superstructures. Based on the experimental results, plausible scenarios for the chiral superstructures of the rodlike molecules embedded in the HNF networks are suggested. In addition, a system comprising BC and rodlike molecules doped with a photoresponsive compound exhibited remarkable photoswitching of CD intensity. According to the isothermal photoinduced phase transition of the embedded molecules in BC molecular HNFs, the observed CD intensities can be dynamically and reversibly modulated. Such a material with easily controllable functionality is of considerable interest in the field of materials science.