Counterion-Induced Nanosheet-to-Nanofilament Transition of Lyotropic Bent-Core Liquid Crystals
Counterion-Induced Nanosheet-to-Nanofilament Transition of Lyotropic Bent-Core Liquid Crystals
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抗衡离子诱导溶致弯核液晶的纳米片到纳米丝的转变
DOI：
10.1021/acs.langmuir.8b02168
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发表时间：
2018
期刊：
影响因子：
3.9
通讯作者：
Liangbin Li
中科院分区：
文献类型：
--
作者：
Daoliang Wang;Qi Yan;Fei Zhong;Yahui Li;Ming Fu;Lingpu Meng;Youju Huang;Liangbin Li
液晶（LC）相变的灵活性使其适用于各种应用，是当代科学，工程和技术的重要研究领域。与大多数报道集中在热致性情况下的六核LC不同，在我们目前的研究中，我们设计并合成了一种完全刚性的六核分子，其中磺酸基团取代了传统的柔性链。系统地研究了各种反离子诱导的超分子液晶相行为。结果发现，近晶相与纳米片倾向于转变为六方相与纳米丝时，磺酸基团的质子被部分取代的碱金属离子。实验结果表明，纳米聚集体和相变是由碱金属离子的置换率而不是分子浓度控制的。另一个有趣的特征是，非手性的α-核分子通过螺旋堆积自组装成柱状，并呈现宏观手性，表明在柱状相中发生了自发的手性对称性破缺。完全刚性的双核分子揭示了令人惊讶的分层分子自组装与近晶到六方相转变，这是以前没有观察到的超分子复合物。这些发现将为基于LC的光子器件、生物系统开关和超分子致动器的应用提供新的可能性。
The smart flexibility of phase transitions in liquid crystals (LCs) makes them suitable for various applications and is an important research field in contemporary science, engineering, and technology. Unlike most reports focused on bent-core LCs in the thermotropic situation, in our present study, we designed and synthesized a fully rigid bent-core molecule with the sulfonic acid group replacing conventional flexible chains. A rich variety of counterion-induced supramolecular LC phase behaviors have been systematically investigated. It was found that the smectic phase with nanosheets tends to transform to the hexagonal phase with nanofilaments when the protons of the sulfonic acid group are partially replaced by alkali metal ions. The experimental results show that the nanoaggregate and phase transition are controlled by the displacing ratio of alkali metal ions rather than the molecular concentration. Another interesting feature is that the achiral bent-core molecules self-assemble into columns by helical stacking and present macroscopic chirality, indicating that spontaneous chiral symmetry breaking occurs in the columnar phase. The fully rigid bent-core molecules reveal surprisingly hierarchical molecular self-assemblies with the smectic-to-hexagonal phase transition, which was not previously observed in supramolecular complexes. The findings will provide new possibilities for applications in LC-based photonic devices, biosystem switches, and supramolecular actuators.