RUI: Analysis of Phase Transitions, Biaxiality and Surface Effects in Chiral Smectic Liquid Crystals

RUI：手性近晶液晶的相变、双轴性和表面效应分析

• 批准号: 1005834
• 负责人: Karl Saunders
• 金额: $ 11万
• 依托单位: California Polytechnic State University Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-15 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1005834&HistoricalAwards=false
• 关键词: RUI; Analysis; Phase; Transitions; Biaxiality

TECHNICAL SUMMARYThis award supports theoretical research and education to investigate phase transitions between smectic structures in liquid crystals, specifically the smectic-A - smectic-C transition. Recently, there has been significant activity in the synthesis and experimental study of technologically promising new chiral liquid crystal materials. These materials exhibit Sm-A - Sm-C transitions with several unusual properties including very strong fluctuation effects, minimal layer contraction, and colossal electro-optical response, which is particularly appealing to the liquid crystal display (LCD) industry. The transition in most of the materials is either continuous and near a tricritical point, or first order.The central aim of this project is to study the chiral Sm-A - Sm-C transition. One focus of the research will be the transition at a tricritical point and the roles played by fluctuations and chirality. The project will also involve analysis of a novel chiral biaxial Sm-A phase, which may occur between the uniaxial Sm-A phase and the Sm-C phase. Biaxiality is a significant issue in the field of liquid crystals, particularly in the search for the elusive and technologically desirable biaxial nematic phase. Another component of the project will be the analysis of the surface electroclinic effect near a first order chiral Sm-A - Sm-C transition. The surface electroclinic effect is a phenomenon, of particular importance in the design of ferroelectric LCDs, whereby the chiral Sm-A - Sm-C transition can be locally induced near a surface. There is reason to believe that the surface electroclinic effect is particularly sensitive near the chiral first order Sm-A - Sm-C phase boundary. This project has both broad scientific and technological implications. It will further the fundamental understanding of phase transitions. Additionally, a theoretical framework for the properties of the unusual new materials discussed above will be technologically valuable in terms of optimizing their applications and guiding the future synthesis of desirable new materials. The wide-ranging applicability of liquid crystals in science and industry adds value to their study, particularly as the nation focuses increasingly on scientific and technological education and innovation. In particular, this award will support the training of undergraduate students in condensed matter and liquid crystals research.NON-TECHNICAL SUMMARYThis award supports theoretical research and education on liquid crystals. Liquid crystals are a fascinating class of soft materials that have a rich variety of internal structures with molecules in spatial arrangements less organized than solid crystals but with directional patterns formed by the orientation of the constituent molecules. So, they can exhibit a range of phases intermediate between liquid and crystalline. These phases can be classified according to the types of order and patterning in their molecular arrangements. Liquid crystal materials exhibit transitions between different molecular arrangements or phases. An everyday example of a phase transition is between water and ice. The rich variety of liquid crystal order and phase transitions has led to considerable scientific interest in their properties. In addition to the fundamental scientific motivation to understand liquid crystals, there is significant technological incentive. Liquid crystals have many wide-ranging applications including LCDs, more explicitly liquid crystal displays, a multibillion dollar industry.This award will facilitate the investigation of a particular phase transition between layered structures in liquid crystals: the smectic-A - smectic-C transition. It will also allow the investigation of a possibly new phase, as well as the surface effects on liquid crystals. This last part of the project is important in the design of LCDs. This project has both broad scientific and technological implications. It will further the fundamental understanding of phase transitions. Additionally, a theoretical framework for the properties of the unusual new materials discussed above will be technologically valuable in terms of optimizing their applications and guiding the future synthesis of desirable new materials. The wide-ranging applicability of liquid crystals in science and industry adds value to their study, particularly as the nation focuses increasingly on scientific and technological education and innovation. In particular, this award will support the training of undergraduate students in condensed matter and liquid crystals research.

该奖项支持理论研究和教育，以研究液晶中近晶结构之间的相变，特别是近晶-A-近晶-C转变。近年来，手性液晶材料的合成和实验研究取得了很大的进展。这些材料表现出Sm-A - Sm-C转变，具有几种不寻常的性质，包括非常强的波动效应，最小的层收缩和巨大的电光响应，这对液晶显示器（LCD）工业特别有吸引力。在大多数材料中，相变要么是连续的，要么是在三临界点附近，要么是一级的。研究的重点之一将是在三临界点的过渡和涨落和手性所发挥的作用。该项目还将涉及分析一种新的手性双轴Sm-A相，它可能发生在单轴Sm-A相和Sm-C相之间。双轴性是液晶领域中的一个重要问题，特别是在寻找难以捉摸的和技术上期望的双轴取向相时。该项目的另一个组成部分将是分析一阶手性Sm-A - Sm-C跃迁附近的表面电斜效应。表面电斜效应是一种在铁电LCD设计中特别重要的现象，由此可以在表面附近局部诱导手性Sm-A - Sm-C跃迁。有理由相信，表面电斜效应是特别敏感的手征一阶Sm-A - Sm-C相界附近。该项目具有广泛的科学和技术影响。这将进一步加深对相变的基本理解。此外，上述不寻常的新材料的性质的理论框架将在优化其应用和指导未来合成所需的新材料方面具有技术价值。液晶在科学和工业中的广泛适用性为其研究增加了价值，特别是随着国家越来越重视科技教育和创新。特别是，该奖项将支持凝聚态和液晶研究的本科生的培训。非技术总结该奖项支持液晶的理论研究和教育。液晶是一类迷人的软质材料，具有丰富多样的内部结构，分子的空间排列不如固体晶体有序，但具有由组成分子的取向形成的方向图案。因此，它们可以表现出介于液体和结晶之间的一系列相。这些相可以根据其分子排列中的顺序和模式的类型进行分类。液晶材料表现出不同分子排列或相之间的转变。相变的一个日常例子是水和冰之间的相变。液晶有序和相变的丰富多样性导致了对其性质的相当大的科学兴趣。除了了解液晶的基本科学动机外，还有重要的技术动机。液晶有许多广泛的应用，包括液晶显示器，更确切地说，液晶显示器，一个数十亿美元的产业。该奖项将促进液晶分层结构之间的一个特殊相变的研究：近晶-A-近晶-C转变。它还将允许研究可能的新相，以及对液晶的表面效应。该项目的最后一部分在LCD的设计中非常重要。该项目具有广泛的科学和技术影响。这将进一步加深对相变的基本理解。此外，上述不寻常的新材料的性质的理论框架将在优化其应用和指导未来合成所需的新材料方面具有技术价值。液晶在科学和工业中的广泛适用性为其研究增加了价值，特别是随着国家越来越重视科技教育和创新。特别是，该奖项将支持凝聚态和液晶研究的本科生的培训。