Excluded Volume and Electrostatic Interactions in Liquid Crystals

排除液晶中的体积和静电相互作用

• 批准号: 0501262
• 负责人: Edward Samulski
• 金额: --
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-06-15 至 2011-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0501262&HistoricalAwards=false
• 关键词: Excluded; Volume; Electrostatic; Interactions; Liquid

This project employs iterative synthetic chemistry in combination with physicochemical characterization (emphasizing nuclear magnetic resonance) to target novel liquid crystal phase symmetries, e.g., biaxial and polar nematic phases, with a goal of delineating the underlying molecular physics. Additionally, the new molecular structures created in this project may point to Liquid Crystal Display (LCD) materials that exhibit more facile electro-optic switching. While the research focus herein is on liquid crystals, these anisotropic fluids may be viewed more generally as an entre to better comprehension of subtle intermolecular interactions in ordinary liquids. Undergraduates (with summer research support) and graduate students are exposed to rigorous training in contemporary synthesis and physical chemistry. Moreover the subject matter is intriguing as well as applicable, and the training enables graduates to pursue a career in the important area of display technologies. Structure-property relations in liquid crystals continue to be a very fertile area for understanding fundamental interactions in soft materials and their associated applications such as Liquid Crystal Displays (LCD)s. In liquids molecular shape considerations-excluded volume interactions-dominate the dynamic, short-range packing, and in some fluids these interactions propagate over mesoscopic scales giving rise to long-range orientational order-the signature of thermotropic liquid crystals. But electrostatic interactions are responsible for condensed phases generally. And in fact, it is the delicate combination of both repulsive and attractive interactions that enable molecules with extreme shapes (rod-like and disc-like) to assemble into a variety of fluid architectures: uniaxial nematics, stratified smectics, columnar discotic phases, and the recently-discovered "banana phases" exhibited by nonlinear molecules. An explosion of Liquid Crystal Displays (LCD)s-a glass "sandwich" whose pixels encapsulate a curious state of matter-has transformed both the desktop and the battlefield in the last decade. LCDs have made images accessible in all areas of science, technology, medicine, government, commerce, and entertainment. Remote imaging makes graphical tracking of severe weather immediately available. It gives physicians an opportunity to "see" patients and monitor intricate medical procedures. Low-cost LCDs make the web accessible in undeveloped countries and LC projectors are essential to high-tech teaching and corporate communications. Chances are that you are reading an electronic version of this abstract on a LCD! We are researching the essential component of these displays, liquid crystal molecules that show electric-field-activated optical properties. Our ultimate goal is to enable a new generation of physical scientists to design new liquid crystals that will continue what the first generation of LCDs did for watches, computers, and cell phones. We anticipate that the new molecules created in our program will lead to more robust LCD materials which in turn, exhibit faster electro-optic switching. In our program undergraduates, vying for competitive summer research support, and graduate students in chemistry and material science are exposed to rigorous training in synthetic and physical chemistry in a subject that is intriguing as well as applicable. The training is designed to enable graduates to pursue a career in the technologically important area of electro-optic displays.

本项目采用迭代合成化学结合物理化学表征（强调核磁共振），以新的液晶相对称为目标，例如双轴和极性向列相，目的是描述潜在的分子物理。此外，在这个项目中创造的新分子结构可能指向液晶显示（LCD）材料，显示出更容易的电光开关。虽然这里的研究重点是液晶，但这些各向异性流体可以被更广泛地视为更好地理解普通液体中微妙的分子间相互作用的中心。本科生（有暑期研究支持）和研究生在现代合成和物理化学方面接受严格的训练。此外，该主题既有趣又适用，培训使毕业生能够在显示技术的重要领域从事职业。液晶的结构-性质关系仍然是理解软材料及其相关应用（如液晶显示器）中基本相互作用的一个非常肥沃的领域。在液体中，分子形状因素（排除体积相互作用）主导着动态的、短程的堆积，在一些液体中，这些相互作用在介观尺度上传播，产生了远距离的取向顺序——热致液晶的特征。但是静电相互作用通常是造成凝聚相的原因。事实上，正是排斥和吸引相互作用的微妙结合，使得极端形状的分子（棒状和圆盘状）能够组装成各种各样的流体结构：单轴向列相、分层微晶、柱状盘状相，以及最近发现的非线性分子所表现出的“香蕉相”。液晶显示器（LCD）是一种玻璃“三明治”，其像素封装了一种奇特的物质状态。在过去的十年里，液晶显示器（LCD）的爆炸式增长改变了桌面和战场。液晶显示器使图像在科学、技术、医学、政府、商业和娱乐的各个领域都可访问。远程成像使恶劣天气的图形跟踪立即可用。它让医生有机会“看到”病人并监控复杂的医疗程序。低成本的液晶显示器使不发达国家可以访问网络，而液晶投影仪对于高科技教学和企业通信至关重要。很有可能你正在液晶显示器上阅读这篇摘要的电子版！我们正在研究这些显示器的基本组成部分，即显示电场激活光学特性的液晶分子。我们的最终目标是让新一代的物理科学家能够设计出新的液晶，延续第一代lcd为手表、电脑和手机所做的一切。我们预计，在我们的项目中创造的新分子将导致更坚固的LCD材料，从而表现出更快的电光开关。在我们的项目中，本科生，竞争有竞争力的夏季研究支持，研究生在化学和材料科学暴露在合成化学和物理化学的严格训练中，这是一个有趣的和适用的主题。该培训旨在使毕业生能够在电光显示技术重要领域从事职业。