Curved confinement directs anchoring-mediated structural transitions in highly chiral liquid crystal shells

IF 3.2 3区 工程技术 Q2 CHEMISTRY, PHYSICAL
Sepideh Norouzi, Jeremy Money, Stiven Villada-Gil, José A. Martínez-González and Monirosadat Sadati
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Abstract

Cholesteric liquid crystals (CLCs) confined in curved geometries exhibit a rich spectrum of defect-mediated morphologies governed by the interplay between chirality, curvature, surface anchoring, and confinement. This study systematically investigates structural transitions in highly chiral CLC shells under asymmetric anchoring conditions, focusing on the effects of shell thickness and curvature on pitch axis reorientation and defect formation. Utilizing microfluidic techniques, we generate core–shell droplets with independently tunable anchoring at inner and outer aqueous interfaces. Transitioning from planar–planar to planar-homeotropic boundary conditions via surfactant-mediated modulation induces profound reorganizations in the director field, giving rise to focal conic domains (FCDs), stripe patterns, and hybrid textures. Optical microscopy reveals that thicker shells favor coherent FCD nucleation, while thinner shells exhibit asymmetric, fragmented domains due to increased spatial frustration and constrained elastic relaxation. In small-diameter shells, high curvature suppresses defect nucleation, promoting the emergence of periodic stripe textures as an energetically favorable alternative. Complementary continuum simulations based on the Landau–de Gennes framework reproduce experimental trends, highlighting anchoring energy thresholds that delineate morphological regimes and confirm the dominance of curvature in stabilizing non-defect-based modulations. The ability to engineer defect architectures and direct pitch axis orientation via geometrical and boundary condition control can open new avenues for designing responsive and reconfigurable optical materials and photonic elements.

Abstract Image

在高手性液晶壳中,弯曲约束指导锚定介导的结构转变
受限于弯曲几何形状的胆甾型液晶(CLCs)表现出丰富的缺陷介导的形态谱,这是由手性、曲率、表面锚定和约束之间的相互作用决定的。本研究系统研究了非对称锚定条件下高手性CLC壳体的结构转变,重点研究了壳体厚度和曲率对俯仰轴重定向和缺陷形成的影响。利用微流体技术,我们在内外水界面产生了具有独立可调锚定的核壳液滴。通过表面活性剂介导的调制,从平面-平面边界条件过渡到平面-各向同性边界条件,在指向场中引起了深刻的重组,产生了焦锥域(FCDs)、条纹图案和混合纹理。光学显微镜显示,较厚的壳层有利于相干FCD成核,而较薄的壳层由于增加的空间挫折和受限的弹性松弛而表现出不对称的碎片化畴。在小直径的壳中,高曲率抑制了缺陷的成核,促进了周期性条纹织构的出现,这是一种有利的能量选择。基于Landau-de Gennes框架的互补连续体模拟再现了实验趋势,突出了锚定能量阈值,该阈值描绘了形态制度,并确认了曲率在稳定非缺陷调制中的主导地位。通过几何和边界条件控制设计缺陷结构和直接俯仰轴方向的能力可以为设计响应性和可重构的光学材料和光子元件开辟新的途径。
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来源期刊
Molecular Systems Design & Engineering
Molecular Systems Design & Engineering Engineering-Biomedical Engineering
CiteScore
6.40
自引率
2.80%
发文量
144
期刊介绍: Molecular Systems Design & Engineering provides a hub for cutting-edge research into how understanding of molecular properties, behaviour and interactions can be used to design and assemble better materials, systems, and processes to achieve specific functions. These may have applications of technological significance and help address global challenges.
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