CAREER: Crystallization of Chiral Liquid Crystals Under Curved Confinement

该奖项全部或部分由《2021年美国救援计划法案》（公法117-2）资助。液晶具有介于传统液体和结晶固体之间的特性和易响应的电特性，是许多显示和电光技术的核心。然而，小型化、弯曲和柔性设备（如显示器、光纤或可穿戴传感器）的出现造成了重大的知识鸿沟，因为弯曲约束下的结晶仍然不太清楚。本项目结合实验和计算研究来发现高手性液晶重新配置其三维晶格以适应弯曲受限边界的控制机制。这些基本的纳米级物理过程是一系列宏观现象的基础，包括响应时间和光子带隙，可用于将软手性液晶的应用从光子学，传感和电子显示扩展到信息技术。PI将这项研究与协同教育和推广活动相结合，包括为少数民族服务机构的学生提供研究培训、课程开发和组织区域“软物质研讨会”，以提高更广泛的科学界对软凝聚态物质的了解。技术摘要：蓝相（bp）是一种具有亚微米立方晶格的手性液晶，具有可见光的布拉格折射和短相干长度，能够实现1毫秒的快速响应时间，使其在显示、光子学和传感应用中具有吸引力。bp的三维立方晶格结构与曲率之间的几何不相容会限制这些纳米结构在弯曲受限空间内的组织，从而导致结构不稳定和拓扑缺陷的出现。在本项目中，采用自上而下的制造策略，系统地将BP软晶体限制在定义良好的弯曲几何形状中，并在多个长度尺度上定制手性实体的自组装。此外，通过电场和机械力的相互作用，研究了BP晶格的重塑，这可能丰富了弯曲几何中BP光带隙的控制手段。这项工作推进了我们对BP三维晶体晶格变形、收缩和重新配置以适应边界表面曲率和响应环境的机制的基本理解。此外，它还为理解和发展强弯曲约束条件下手性材料中可能出现的复杂skyrmion结构的设计原理提供了基础。了解这种“曲率导向”自组装和晶体生长的基本基础可能会促进定制BP软纳米晶体的使用，并使具有实际设备所需的独特性能的新型快速响应材料的开发成为可能，例如柔性显示器，可穿戴传感器和信息存储设备。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).NON-TECHNICAL ABSTRACT Liquid crystals, with properties between conventional liquids and crystalline solids and facile electric response, are the heart of many displays and electro-optic technologies. However, the advent of miniaturized, curved, and flexible devices such as displays, fiber optics, or wearable sensors has created a significant knowledge gap as crystallization under curved confinement remains less well-understood. This project combines experimental and computational studies to discover the governing mechanisms by which high chirality liquid crystals reconfigure their 3D crystal lattices to adapt to curved confined boundaries. These basic nanoscale physical processes underlie a range of macroscopic phenomena, including response time and photonic bandgap, which can be utilized to expand the applications of soft chiral liquid crystals from photonics, sensing, and electronic displays to information technologies. PI combines this research with synergistic educational and outreach activities, including research training for students from minority-serving institutions, curriculum development, and organizing a regional “Soft Matter Workshop” to enhance the exposure of the broader scientific community to soft condensed matter. TECHNICAL ABSTRACTBlue phases (BPs) are chiral liquid crystals with submicron cubic-crystalline lattices that exhibit Bragg refraction of visible light and short coherent length, enabling fast response times of 1 ms, making them attractive for display, photonics, and sensing applications. Geometrical incompatibility between the three-dimensional cubic lattice structure of BPs and curvature can constrain the organization of these nanostructures within curved confined spaces, which can lead to structural instability and the emergence of topological defects. In this project, top-down fabrication strategies are employed to systematically confine BP soft crystals in well-defined curved geometries and tailor the self-assembly of chiral entities over multiple length scales. Moreover, reshaping the BP lattices through interactions with electric fields and mechanical forces are examined, which may enrich the means of controlling the light bandgap of BPs in curved geometries. This work advances our fundamental understanding of the mechanism by which BP 3D crystalline lattices deform, contract, and reconfigure to adapt to the curvature of the bounding surfaces and respond to the environment. Moreover, it provides a foundation for understanding and developing design principles of complex skyrmion structures, which may appear in chiral materials under strong curved confinement. Understanding the fundamental underpinnings of this “curvature-guided” self-assembly and crystal growth may catalyze the use of tailored BP soft nanocrystals and enable the development of new fast-response materials with unique properties needed for practical devices, such as flexible displays, wearable sensors, and information storage devices.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.