Topology Driven Flows in Chromonic Liquid Crystals

有色液晶中的拓扑驱动流动

• 批准号: 1838977
• 负责人: Jorge Vinals
• 金额: $ 32.75万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-11-15 至 2023-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1838977&HistoricalAwards=false
• 关键词: Topology; Driven; Flows; Chromonic; Liquid; Topology; Driven; Flows; Chromonic; Liquid

NONTECHNICAL SUMMARYThis award supports theoretical and computational research, and education on defects in liquid crystals.Liquid crystals are made of rod like molecules that display complex spatial arrangements, though intermediate between perfectly ordered crystals and completely disordered liquids. Their combined ability to flow like a fluid, while transmitting directional forces and possessing direction dependent properties like a crystal, make them suitable for a wide range of applications. However, because of their weak crystallinity, defects are abundant in laboratory samples. Although this property has long been considered deleterious for applications, recent research has uncovered a host of new and unexpected properties of these materials that follow precisely from the existence of defects, and from their manipulation. Examples include guided transport of other molecular species or biological agents, the development of mechanical switches activated by light or electric fields, and even analogies involving biological response. This project is aimed to improve existing theoretical models that describe defected liquid crystals, and any accompanying transport. New models detailing the structure and motion of defects will be developed, including their interaction with transport of mass or fluid flow. The aim is to develop a predictive framework that describes the response of the liquid crystal to operating conditions or external influences. The specific focus of the research is on lyotropic chromonic liquid crystals, substances in which the liquid crystalline behavior is induced by using an appropriate dilution solvent to change the concentration of the rod like molecules. They have been known for a long time as dyes (including food dyes), and are analogs of lung surfactant agents. They are also bio-compatible liquid crystals, and are currently being developed for live cell steering or sorting. This class of liquid crystals features unusually large defect features that make them amenable to optical analysis, and comparison to theory.The research will be used to further develop and enhance an interdisciplinary course on computation in the physical sciences. Students participating in the project will benefit from substantial training and collaboration opportunities at the Minnesota Supercomputing Institute.TECHNICAL SUMMARYThis award supports theoretical and computational research, and education focused on the systematic study of topological defects, equilibrium morphologies, and dynamical evolution of nematic-isotropic interfaces in lyotropic chromonic liquid crystals. Configurations considered include a pure nematic phase, or the biphasic region of coexistence between nematic and isotropic phases. This study is motivated by ongoing experiments that show that the characteristic microscopic scale of chromonics is on the order of microns, much larger than the 10 nm size in conventional thermotropic liquid crystals. Such large scales allow modern optical imaging techniques to resolve defect cores and two-phase interfaces, and hence to extract the parameters of mesoscopic free energy models down to an unprecedented spatial scale. This information opens the door to critical and quantitative tests of current nonlinear, gradient theories of nonequilibrium for nematics. In addition, the unusual morphology of nematic domains (tactoids), and their nonequilibrium evolution, are expected to lead to novel behavior due to the complexity of interactions at this scale, including strong anisotropy, nonlocal elastic interactions due to topological defects, and mesocale biaxiality. Defect driven flows and the dynamics of biological matter suspended in the chromonic are among planned investigations. These are under active scrutiny because of potential applications in flow control in microfluidics and optobiological devices, in the biomedical field for cell sorting and bio sensing.The research will be used to further develop and enhance an interdisciplinary course on computation in the physical sciences. Students participating in the project will benefit from substantial training and collaboration opportunities at the Minnesota Supercomputing Institute.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.

非技术摘要这一奖项支持理论和计算研究，以及有关液晶缺陷的教育。流动晶体是由像分子这样的杆制成的，这些分子表现出复杂的空间排列，尽管中间有序的晶体和完全无序的液体之间。 它们的合并能力像流体一样流动，同时传递定向力和具有晶体等方向依赖性的特性，使它们适合于广泛的应用。但是，由于其结晶度弱，实验室样品中的缺陷很大。尽管长期以来一直认为该属性在应用中被认为是有害的，但最近的研究发现了这些材料的许多新的和意外的特性，这些特性正是由于缺陷的存在及其操纵而遵循的。例如，其他分子物种或生物学剂的转运，光或电场激活的机械开关的发展，甚至涉及生物学反应的类比。该项目旨在改善描述液晶缺陷和任何随附的运输的现有理论模型。将开发详细介绍缺陷结构和运动的新模型，包括它们与质量或流体流的运输相互作用。目的是开发一个预测框架，描述液晶对工作条件或外部影响的响应。该研究的特定重点是溶式染色体液体晶体，其中通过使用适当的稀释溶剂来改变杆子类似分子的浓度来诱导液晶行为。它们很长一段时间以染料（包括食物染料）而闻名，并且是肺表面活性剂的类似物。它们也是与生物兼容的液晶，目前正在开发用于现场细胞转向或分类。这类液体晶体具有异常大的缺陷特征，使其可以与光学分析相提并论，并与理论进行比较。该研究将用于进一步发展和增强物理科学中计算的跨学科课程。参加该项目的学生将受益于明尼苏达州超级计算研究所的大量培训和合作机会。技术摘要奖支持理论和计算研究，并侧重于对拓扑缺陷，平衡形态和固有性异位界面的动态进化的系统研究。所考虑的构型包括纯列相，或者和各向同性阶段之间共存的双相区域。这项研究是由正在进行的实验激励的，这些实验表明，染色体的特征性微观尺度是在微米的顺序上，远大于常规热液晶中的10 nm尺寸。如此大的尺度使现代的光学成像技术可以解决缺陷核心和两相界面，从而将介观自由能模型的参数提取到前所未有的空间尺度。该信息为当前非线性非平衡性列明氏体的非线性梯度理论进行关键和定量测试打开了大门。此外，由于这种规模的相互作用的复杂性，包括强度强的各向异性，由于拓扑缺陷，由于拓扑缺陷和中间的双轴性，预期列明结构域（触觉）及其非平衡进化的异常形态及其非平衡进化。 缺陷驱动的流量和悬浮在染色体中的生物物质动态是计划的研究。由于在生物医学领域中，用于细胞分选和生物传感的生物医学领域中，这些研究将用于进一步开发和增强物理科学中计算的跨学科课程。参加该项目的学生将受益于明尼苏达州超级计算研究所的大量培训和合作机会。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的评估标准来通过评估来获得支持的。