A Unified Framework for Description of Lyotropic and Active Liquid Crystals Far from Equilibrium

非技术总结该奖项支持理论和计算研究和教育，以促进对液晶(LC)的基本理解。液晶材料结合了液体的一些特性(如流动能力)和固体的一些特性(如高度有序的分子结构、弹性和可控的光学特性)。从简单的温度计到最先进的显示技术，它们可以在各种各样的设备中找到。到目前为止，LCS的应用大多依赖于热致材料，其结构和外观随着温度的变化而变化。人们对溶致液晶知之甚少，溶致液晶在自然界中含量丰富，其行为可以通过在溶液中的浓度而不是温度来调节。溶致材料是生物学和生命的核心。它们是水溶性的，例如，它们提供了使细胞保持形状、移动和繁殖的支架。它们还负责一些生物有机体对外部提示做出反应时可能经历的颜色变化。从技术的角度来看，它们可以为生物和化学传感器的开发提供一个新的平台，或者为开发主动的、自主的物质提供一个新的平台，这些物质在提供必要的指令后显示出运动或自我修复的特征。该项目的目标是创建分子模型，以描述溶致液晶的行为。通过这些模型，将有可能确定特定的分子特征如何影响结构和对外部输入的响应，并对这类重要材料的结构和性能达成基本了解。这一理解将成为溶致系统在新兴技术中应用的基础。该项目还将涉及在多学科环境中对学生进行最先进的理论和计算技术的培训。此外，与芝加哥科学与工业博物馆合作，将为学生提供培训和公开演讲机会，帮助他们发展沟通和演讲技能。一个有针对性的暑期计划将使年轻一代处于危险中的当地高中生接触到科学在技术前沿的兴奋。技术总结该奖项支持理论和计算研究和教育，以促进对液晶(LC)的基本理解。我们对液晶材料的大部分了解都来自于对热致油的研究，在热致油中，温度被用来控制相行为。人们对分层组装的LC知之甚少，其中包括溶致体系，其形态可以通过温度和浓度控制，以及活性向列生物聚合物，其中自主运动或活性可以通过化学手段产生。分层组装的液晶具有相当重要的意义，因为它们可以在水中制备，并且是生物相容的。此外，它们经常产生介观结构，其特征尺寸可以控制，并且比热致液晶中遇到的要长得多。液晶分子在表面或界面的排列(或锚定)可以通过物理和化学处理来控制，材料的整体取向(或指向角)可以进一步通过外场来操纵。对于分层组装的LC，这两个元素--表面控制和整体控制--并没有得到很好的理解。更具挑战性的问题，包括内部结构和动态之间的关系，以前很少被讨论过。重要的是，与LC相关的技术从理论和模拟提供的见解中受益匪浅。本项目致力于发展一种理论和计算形式，将热致液晶所达到的理解水平带到溶致液晶的研究中。这项工作的一个中心特征将是阐明溶致材料中出现的缺陷的性质。根据介元的分子特性(例如，它们的长度或柔性)，这样的模数可能会有很大的变化，并导致完全不同的缺陷结构和动力学。耐人寻味的问题，包括内部结构、动态和自发、定向流动的出现之间的关系，现在才刚刚开始解决。新的理论形式将大大提高目前对分层组装液晶的理解，这些新的理论形式能够描述在这种材料中出现的中间相，无论是在平衡状态下还是在平衡之外。这个项目的中心目标是发展这种形式主义，并应用它们来理解表面活性分子或纳米颗粒在空间不同区域的排列或分离，以及有序、动态结构的形成。这些模型将依赖于根据实验信息产生的材料特性和见解，以及在需要时更细、更粗层次的描述。该项目还将涉及在多学科环境中对学生进行最先进的理论和计算技术的培训。此外，与芝加哥科学与工业博物馆合作，将为学生提供培训和公开演讲机会，帮助他们发展沟通和演讲技能。一个有针对性的暑期项目将让年轻一代处于危险之中的当地高中生接触到科技前沿的科学带来的兴奋。

NONTECHNICAL SUMMARYThis award supports theoretical and computational research and education to advance the fundamental understanding of liquid crystals (LCs). Liquid crystalline materials combine some of the properties of liquids, such as the ability to flow, and some of the properties of solids, such as a highly ordered molecular structure, elasticity, and controllable optical characteristics. They are found in a wide array of devices, ranging from simple thermometers to state-of-the-art display technologies. Most applications of LCs to date have relied on thermotropic materials, whose structure and appearance changes with temperature. Less is known about lyotropic LCs, which are abundant in nature, and whose behavior can be tuned through their concentration in a solution, as opposed to temperature.Lyotropic materials are central to biology and life. They are water soluble, and they provide, for example, the scaffolds that allow cells to maintain their shape, move, and multiply. They are also responsible for the color changes that some biological organisms can undergo in response to external cues. From a technological point of view, they could provide a new platform for the development of biological and chemical sensors, or for the development of active, autonomous matter, that exhibits motion or self-healing characteristics when provided the necessary instructions. The goal of this project is to create molecular models that will permit description of the behavior of lyotropic LCs. Through these models, it will be possible to determine how particular molecular characteristics influence structure and response to external inputs, and to arrive at a fundamental understanding of the structure and properties of this important class of materials. That understanding will then serve as the basis for applications of lyotropic systems in emerging technologies.The project will also involve the training of students on state-of-the-art theoretical and computational techniques within a multidisciplinary environment. In addition, and in collaboration with the Museum of Science and Industry of Chicago, the students will be provided with training and public speaking opportunities that will help them develop communication and presentation skills. A targeted summer program will expose younger generations of at-risk local high-school students to the excitement of science at the forefront of technology.TECHNICAL SUMMARYThis award supports theoretical and computational research and education to advance the fundamental understanding of liquid crystals (LCs). Most of our understanding of liquid crystalline materials has been derived from studies of thermotropic oils, where temperature is used to control phase behavior. Less is known about hierarchically assembled LCs, which include lyotropic systems whose morphology can be controlled by temperature and concentration, and active nematic biopolymers, where autonomous motion or activity can be engendered by chemical means. Hierarchically assembled LCs are of considerable importance because they can be prepared in water and are biocompatible. Furthermore, they often give rise to mesoscopic structures whose characteristic dimensions can be controlled, and are considerably longer than those encountered in thermotropic LCs. The arrangement (or anchoring) of LC molecules at a surface or interface can be controlled through physical and chemical treatments, and the overall orientation (or director) of the material can be further manipulated by external fields. For hierarchically assembled LCs, these two elements, surface and bulk control, are not well understood. More challenging questions, including the relations between internal structure and dynamics, have rarely been addressed before. Importantly, LC-related technologies have benefited considerably from insights provided by theory and simulation. This project seeks to develop a theoretical and computational formalism that will bring the same level of understanding that has been achieved with thermotropic LCs to the study of lyotropic LCs. A central feature of the work will be to elucidate the nature of the defects that arise in lyotropic materials. Depending on the molecular characteristics of the mesogens (e.g. their length or flexibility), such moduli could vary significantly, and lead to completely different defect structures and dynamics. Intriguing questions, including the relations between internal structure, dynamics, and the emergence of spontaneous, directional flows, are only now beginning to be addressed. The current understanding of hierarchically assembled LCs will be advanced considerably by new theoretical formalisms capable of describing the mesophases that arise in such materials, both at equilibrium and beyond equilibrium. The central aim of this project is to develop such formalisms, and to apply them to understand the arrangement or segregation of surface-active molecules or nanoparticles in distinct regions of space, and the formation of ordered, dynamic structures. Such models will rely on the material properties and insights generated on the basis of experimental information and, when needed, finer, coarse-grained levels of description.The project will also involve the training of students on state-of-the-art theoretical and computational techniques within a multidisciplinary environment. In addition, and in collaboration with the Museum of Science and Industry of Chicago, the students will be provided with training and public speaking opportunities that will help them develop communication and presentation skills. A targeted summer program will expose younger generations of at-risk local high-school students to the excitement of science at the forefront of technology.