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.

非技术摘要表面在液晶显示器的核心液晶（LC）的取向中起着重要的作用。目前，仅使用简单形式的对准，并且这些对准对于今天的显示器已经足够。 然而，未来具有更大功能的设备将取决于开发更复杂的表面对准。 一种可能性是使用在微观水平上形成图案的表面，以将手性或手性引入液晶的排序中。 手征--你的右手不是左手的镜像--在生物学和化学等许多领域发挥着重要作用。 事实上，许多药物必须制备成具有特定手性（右手或左手）才能有效。 在这个项目中，首席研究员和他的团队将探索通过图案化它们接触的表面将手性引入液晶的方法。 然后，他们将研究这些系统，以确定发展出什么样的新模式，这些新模式引入了什么样的力，以及它们如何用于更有效地分离具有不同手性的分子，如药物。 参与这些研究的学生，从高中到研究生院，将接受最先进技术的培训，并将与来自世界各地的合作者合作。 技术摘要表面在无数的系统中起着决定性的作用，这在液晶中尤其如此。 通过在纳米尺度上机械地定制表面结构，PI操纵相邻液晶的行为和对称性，促进新的现象，应用以及对基本物理和化学性质的更深刻理解。 本计画主要探讨非手性液晶表面的手征性、诱导手征性及与手征性相关的力。 近年来，PI已经开发出强大的技术来建立控制手性在表面使用固有的非手性材料和图像液晶取向纳米尺度上。 他正在逐步提高这些技术，并解决最具开创性的问题，其中手性起源于界面。 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;在小到2-3微米的尺度上空间控制对映体分离;检查与手性“偶极子”相关的力;在2-3微米尺度下产生手性拓扑缺陷，包括手性缺陷，并将它们用作手性纳米颗粒的陷阱;以及圣杯：了解手征感应的强度和穿透深度。 私家侦探？的团队开发了一系列实验工具，包括但不限于光学显微镜和光学纳米层析成像（PI对近场扫描光学显微镜的修改），原子力显微镜，AFM和电子束纳米光刻，以及椭圆偏振仪。 通过利用PI的能力，从非手性材料中创建精致定制的手性基板，并将液晶取向成像到60 x 60 x 1 nm的x，y，z维度，这项工作正在改变我们对表面手性及其对各向异性流体的影响的概念和方法。 特别是，它导致大大改善的方法，以创造空间控制的手性在表面，量化和理解的表面诱导的手性在其他非手性分子，其表现在其他物理现象。 这些问题跨越多个学科，因为手性的后果出现在生物学，化学，物理学，医学和药理学中。 这项研究正在引起许多新的现象，并建立新的科学范式的表面手性和液晶。

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 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

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

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