Dietrich Clarissa F, Rudquist Per, Collings Peter J, Giesselmann Frank
Institute of Physical Chemistry, University of Stuttgart, 70569 Stuttgart, Germany.
Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Göteborg, Sweden.
Langmuir. 2021 Mar 2;37(8):2749-2758. doi: 10.1021/acs.langmuir.0c03500. Epub 2021 Feb 12.
Recent studies have shown that lyotropic nematic liquid crystals (LLCs) are exceptional in their viscoelastic behavior. In particular, LLCs display a remarkable softness to twist deformations, which may lead to chiral director configurations under achiral confinement despite the absence of intrinsic chirality. The twisted escaped radial (TER) and the twisted polar (TP) are the two representative reflection symmetry breaking director configurations in the case of cylindrical confinement with homeotropic anchoring. We demonstrate how such reflection symmetry breaking of micellar LLCs under cylindrical confinement is affected by intrinsic chirality, introduced by the addition of a chiral dopant. Similarities and differences between the effects of intrinsic chirality on the defect-free TER configuration, and on the TP configuration incorporating two half-unit twist disclination lines, are discussed. In the TP case, topological constraints facilitate stable heterochiral systems even in the presence of a small amount of chiral dopant, with unusual regions of rapidly reversing handedness between homochiral domains. At moderate dopant concentrations, the TP structure becomes homochiral. At high dopant concentrations, for which the induced cholesteric pitch is much smaller than the diameter of the capillary, the cholesteric fingerprint structure develops.
最近的研究表明，溶致液晶（LLCs）在其粘弹性行为方面表现出色。特别是，LLCs对扭曲变形表现出显著的柔软性，这可能导致在手性受限条件下形成手性指向矢构型，尽管不存在内在手性。扭曲逃逸径向（TER）和扭曲极性（TP）是在垂直锚定的圆柱形受限情况下两种具有代表性的破坏反射对称性的指向矢构型。我们展示了在圆柱形受限条件下，添加手性掺杂剂引入的内在手性如何影响胶束LLCs的这种反射对称性破坏。讨论了内在手性对无缺陷TER构型以及对包含两条半单位扭曲向错线的TP构型的影响之间的异同。在TP情况下，即使存在少量手性掺杂剂，拓扑约束也有利于稳定的异手性系统，在手性畴之间存在快速反转手性的异常区域。在中等掺杂浓度下，TP结构变为同手性。在高掺杂浓度下，诱导的胆甾相螺距远小于毛细管直径，胆甾相指纹结构形成。
