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

描述远离平衡态的溶致液晶和活性液晶的统一框架

基本信息

批准号：
1710318
负责人：
Juan De Pablo
金额：
$ 36.11万
依托单位：
University of Chicago
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-01 至 2020-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1710318&HistoricalAwards=false
关键词：
Unified Framework Description Lyotropic Active

项目摘要

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.

非技术摘要该奖项支持理论和计算研究及教育，以增进对液晶 (LC) 的基本了解。液晶材料结合了液体的一些特性（例如流动能力）和固体的一些特性（例如高度有序的分子结构、弹性和可控光学特性）。它们存在于各种设备中，从简单的温度计到最先进的显示技术。迄今为止，液晶的大多数应用都依赖于热致材料，其结构和外观随温度而变化。人们对溶致液晶知之甚少，这种液晶在自然界中含量丰富，其行为可以通过其在溶液中的浓度（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，并且它们提供了例如允许细胞保持其形状、移动和繁殖的支架。它们还负责一些生物有机体响应外部提示而发生的颜色变化。从技术角度来看，它们可以为生物和化学传感器的开发，或为活性自主物质的开发提供新的平台，这些物质在提供必要的指令时表现出运动或自愈特性。该项目的目标是创建分子模型来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，并基本了解这一类重要材料的结构和性质。这种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，帮助他们培养沟通和演讲技能。有针对性的暑期项目将使年轻一代的高危当地高中生接触到前沿技术的科学乐趣。技术摘要该奖项支持理论和计算研究及教育，以增进对液晶 (LC) 的基本了解。我们对液晶材料的大部分理解都源自对热致油的研究，其中温度用于控制相行为。人们对分层组装的液晶知之甚少，其中包括形态可通过温度和浓度控制的溶致系统，以及可通过化学手段产生自主运动或活性的活性向列生物聚合物。分级组装的液晶非常重要，因为它们可以在水中制备并且具有生物相容性。此外，它们通常会产生特征尺寸可以控制的介观结构，并且比热致液晶中遇到的介观结构要长得多。液晶分子在表面或界面上的排列（或锚定）可以通过物理和化学处理来控制，并且材料的整体取向（或导向器）可以通过外部场进一步操纵。对于分层组装的液晶，表面和体积控制这两个要素还没有被很好地理解。更具挑战性的问题，包括内部结构和动力学之间的关系，以前很少被解决。重要的是，LC 相关技术从理论和模拟提供的见解中受益匪浅。该项目旨在开发一种理论和计算形式，将热致液晶的理解水平带入溶致液晶的研究。这项工作的一个中心特点是阐明溶致材料中出现的缺陷的性质。根据介晶的分子特征（例如它们的长度或灵活性），这种模量可能会有很大变化，并导致完全不同的缺陷结构和动力学。一些有趣的问题，包括内部结构、动力学和自发定向流的出现之间的关系，现在才开始得到解决。目前对分层组装液晶的理解将通过能够描述此类材料中在平衡和超出平衡时出现的中间相的新理论形式而大大推进。该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不同空间区域的排列或分离，以及有序动态结构的形成。这些模型将依赖于基于实验信息产生的材料特性和见解，以及在需要时更精细、粗粒度的描述。该项目还将包括对学生进行最先进的理论和知识培训。多学科环境中的计算技术。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，帮助他们培养沟通和演讲技巧。有针对性的暑期项目将使年轻一代的高危当地高中生接触到前沿技术的科学乐趣。