Surfaces, Chirality, and Liquid Crystals

表面、手性和液晶

• 批准号: 1505389
• 负责人: Charles Rosenblatt
• 金额: $ 46.51万
• 依托单位: Case Western Reserve University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2020-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1505389&HistoricalAwards=false
• 关键词: Surfaces; Chirality; Liquid; Crystals

NON-TECHNICAL ABSTRACTSurfaces play an important role in aligning the liquid crystals (LC) that are the core of LC displays. Currently, only simple forms of alignment have been used and these have been adequate for today's displays. However, future devices with even greater capabilities will depend on developing more complex surface alignments. One possibility is to use surfaces patterned at the microscopic level to introduce chirality, or handedness, into the ordering of the liquid crystals. Chirality - the fact that your right hand is not a mirror image of the left - plays an important role in many areas such as biology and chemistry. In fact, many pharmaceuticals must be prepared with a specific chirality (either right or left handed) to be effective. In this project the principal investigator and his team will explore ways of introducing chirality into liquid crystals by patterning the surface they are in contact with. They will then study these systems to determine what new patterns develop, what are the forces introduced by these new patterns and how they can be used to more effectively separate molecules with different chirality, such as pharmaceuticals. The students involved in these studies, from high school to graduate school, will be trained in state-of-the-art techniques and will work with collaborators from around the world. TECHNICAL ABSTRACTSurfaces play a defining role in myriad systems; this is especially true of liquid crystals. By mechanically tailoring the surface structure on nanoscopic length scales, the PI manipulates the behavior and symmetry of the adjacent liquid crystal, facilitating new phenomena, applications, and a more profound understanding of fundamental physical and chemical properties. This project focuses on imposed chirality at the surface, induced chirality in the achiral liquid crystal, and forces associated with chirality. In recent years the PI has developed powerful techniques both to establish controlled chirality at surfaces using inherently achiral materials and to image liquid crystal orientation on nanoscopic length scales. He is ratcheting up these techniques and addressing the most seminal issues in which chirality originates at an interface. The work has several objectives, including: optimization of mechanically-generated chiral surfaces; understanding the influence of surface chirality on liquid crystal symmetry and anchoring; spatially-controlling enantiomeric segregation at scales as small as 2-3 micrometers; examining forces associated with chiral "dipoles"; creating chiral topological defects, including chiral defects, at the 2-3 micrometer scale and using them as traps for chiral nanoparticles; and the Holy Grail: understanding chiral induction, both the strength and penetration depth. The PI?s team exploits a battery of experimental tools, including - but not limited to - optical microscopy and optical nanotomography (the PI's modification of near field scanning optical microscopy), atomic force microscopy, AFM and electron beam nanolithography, and ellipsometry. By exploiting the PI's ability to create exquisitely tailored chiral substrates from achiral materials and to image liquid crystal orientation down to x,y,z dimensions of 60 x 60 x 1 nm, this work is transforming our conceptions about - and methodology toward - surface chirality and its effects on anisotropic fluids. In particular, it is leading to vastly improved methods to create spatially-controlled chirality at surfaces, the quantification and understanding of surface-induced chirality in otherwise achiral molecules, and its manifestation in other physical phenomena. These issues cut across multiple disciplines, as consequences of chirality appear throughout biology, chemistry, physics, medicine, and pharmacology. The research is giving rise to a host of novel phenomena, and establishing new scientific paradigms for surface chirality and liquid crystals.

非技术摘要表演在对齐液晶（LC）方面起重要作用，这是LC显示的核心。当前，仅使用了简单的对齐形式，这些形式足以适合当今的显示器。 但是，具有更大功能的未来设备将取决于开发更复杂的表面对齐。 一种可能性是使用在微观水平上模式的表面将手性或惯用性引入液晶的顺序。 手性 - 右手不是左派的镜像，这一事实在许多领域（例如生物学和化学）中起着重要作用。 实际上，许多药物必须采用特定的手性（右手或左手）的特定手学准备才能有效。 在这个项目中，首席研究员和他的团队将通过对与之接触的表面进行构图来探索将手性引入液晶的方法。 然后，他们将研究这些系统以确定哪些新模式的发展，这些新模式引入了哪些力以及如何使用不同手性的分子来更有效地分离分子，例如药物。 从高中到研究生院，参与这些研究的学生将接受最先进的技术培训，并将与来自世界各地的合作者合作。 技术摘要曲面在众多系统中起着决定性的作用；液晶尤其如此。 通过机械定制纳米镜长尺度上的表面结构，PI可以操纵相邻液晶的行为和对称性，从而促进新现象，应用以及对基本物理和化学特性的更深入的了解。 该项目的重点是在表面上施加的手性，诱发液晶的手性以及与手性相关的力。 近年来，PI开发了功能强大的技术，既可以使用固有的精神材料在表面上建立受控的手性，又可以在纳米镜面长度上进行液晶取向。 他正在研究这些技术，并解决了手性发起的最开创性问题。 这项工作有几个目标，包括：优化机械生成的手性表面；了解表面手性对液晶对称性和锚定的影响；在尺度小至2-3微米处的空间控制对映体分离；检查与手性“偶极子”相关的力；在2-3微米尺度上产生手性拓扑缺陷，包​​括手性缺陷，并将其用作手性纳米颗粒的陷阱；和圣杯：理解手性诱导的力量和渗透深度。 PI的团队利用了一系列实验工具，包括（但不限于 - 光学显微镜和光学纳米摄影）（PI对近场扫描光学显微镜的修改），原子力显微镜，AFM和电子束纳米函数术和椭圆指数。 通过利用PI创建精美量身定制的手性底物的能力，将液晶取向降低到X，Y，Z尺寸为60 x 60 x 1 nm的X，Y，Z尺寸，这项工作正在将我们的概念转变为 - 表面性手学及其对向区流体的影响。 特别是，这导致了在表面上创建空间控制的手性的大大改进的方法，对否则痛苦分子中表面诱导的手性的量化和理解及其在其他物理现象中的表现。 这些问题跨越了多个学科，因为手性的后果出现在整个生物学，化学，物理，医学和药理学中。 这项研究引起了许多新现象，并为表面手性和液晶建立了新的科学范例。

项目成果

Persistence of Smectic-A Oily Streaks into the Nematic Phase by UV Irradiation of Reactive Mesogens

• DOI: 10.3390/cryst7120358
• 发表时间: 2017-12
• 作者: Ines Gharbi;Amine Missaoui;D. Demaille;E. Lacaze;C. Rosenblatt

Decomposition vs. Escape of Topological Defects in a Nematic Liquid Crystal

向列液晶中拓扑缺陷的分解与逃逸

• 发表时间: 2017
• 期刊: Soft matter
• 影响因子: 3.4
• 作者: Murray, Bryce S;Kralk, Samo;Rosenblatt, Charles
• 通讯作者: Rosenblatt, Charles

Chiral Polymeric Nanocapsules and Their Use for Conformational Deracemization of Liquid Crystals

• DOI: 10.1021/acs.jpcc.8b06005
• 发表时间: 2018-08-09
• 期刊: JOURNAL OF PHYSICAL CHEMISTRY C
• 影响因子: 3.7
• 作者: Zoabi, Amani;Santiago, Melvin G.;Abu-Reziq, Raed
• 通讯作者: Abu-Reziq, Raed

Chiral organosilica particles and their use as inducers of conformational deracemization of liquid crystal phases

• DOI: 10.1016/j.cplett.2018.02.050
• 发表时间: 2018-03
• 期刊: Chemical Physics Letters
• 影响因子: 2.8
• 作者: Orit Cohen;A. Ferris;Raymond Adkins;R. Lemieux;D. Avnir;D. Gelman;C. Rosenblatt

Electroclinic effect in a chiral paranematic liquid-crystal layer above the bulk nematic-to-isotropic transition temperature

手性副相液晶层中高于体向列向各向同性转变温度的电致效应

• DOI: 10.1103/physreve.93.022701
• 发表时间: 2016
• 期刊: Physical Review E
• 影响因子: 2.4
• 作者: Nemitz, Ian R.;Lacaze, Emmanuelle;Rosenblatt, Charles
• 通讯作者: Rosenblatt, Charles