Elastic Instability of Cubic Blue Phase Nano Crystals in Curved Shells
Elastic Instability of Cubic Blue Phase Nano Crystals in Curved Shells
复制标题
曲壳立方蓝相纳米晶体的弹性不稳定性
DOI：
10.1021/acsnano.2c02799
复制
发表时间：
2022
期刊：
影响因子：
17.1
通讯作者：
Sadati, Monirosadat
中科院分区：
文献类型：
--
作者：
Norouzi, Sepideh;Tavera-Vazquez, Antonio;Ramirez-de Arellano, Johanan;Kim, Dae Seok;Lopez-Leon, Teresa;de Pablo, Juan J.;Martinez-Gonzalez, Jose A.;Sadati, Monirosadat
许多结晶过程，包括生物矿化和冰冻，发生在小而弯曲的体积中，表面曲率会使晶体应变，导致不寻常的构型和缺陷的形成。然而，曲率在结晶中的作用仍然知之甚少。在这里，我们研究了弯曲约束下蓝相(BP)液晶的结晶，这为理解BP重新配置其三维晶格结构以适应曲率的机制提供了见解。BPS是高手性液晶分子排列成体心(BPI)或简单立方体(BPII)对称性的三维组装。具有亚微米立方晶晶格的BPS具有可调的布拉格反射和对电场等外部刺激的亚毫秒响应时间，使其对先进的光子材料具有吸引力。在这项工作中，我们系统地研究了具有明确曲率和边界条件的球壳中的BPS。还研究了壳层在室温下的光学行为，在室温下形成了胆甾相结构。在胆甾相中，垂直锚定在壳层表面产生焦点圆锥形微区，随着曲率程度的增加，这些微区转变为条纹图案。我们的结果表明，较高的曲率和较强的空间限制都会破坏BPI的稳定性，并重新配置该相位以适应BPII的结构和光学特性。我们还表明，曲率和约束的耦合使Skyrmions比平面几何中观察到的更厚的厚度成核。这些发现对于将BPS集成到小型化和曲面/柔性设备中尤其重要，这些设备包括柔性显示器、可穿戴传感器和智能面料。
Many crystallization processes, including biomineralization and ice-freezing, occur in small and curved volumes, where surface curvature can strain the crystal, leading to unusual configurations and defect formation. The role of curvature on crystallization, however, remains poorly understood. Here, we study the crystallization of blue phase (BP) liquid crystals under curved confinement, which provides insights into the mechanism by which BPs reconfigure their three-dimensional lattice structure to adapt to curvature. BPs are a three-dimensional assembly of high-chirality liquid crystal molecules arranged into body-centered (BPI) or simple cubic (BPII) symmetries. BPs with submicrometer cubic-crystalline lattices exhibit tunable Bragg reflection and submillisecond response time to external stimuli such as an electric field, making them attractive for advanced photonic materials. In this work, we have systematically studied BPs confined in spherical shells with well-defined curvature and boundary conditions. The optical behavior of shells has also been examined at room temperature, where the cholesteric structure forms. In the cholesteric phase, perpendicular anchoring generates focal conic domains on the shell’s surface, which transition into stripe patterns as the degree of curvature increases. Our results demonstrate that both higher degrees of curvature and strong spatial confinement destabilize BPI and reconfigure that phase to adopt the structure and optical features of BPII. We also show that the coupling of curvature and confinement nucleates skyrmions at greater thicknesses than those observed for a flat geometry. These findings are particularly important for integrating BPs into miniaturized and curved/flexible devices, including flexible displays, wearable sensors, and smart fabrics.