Symmetry and Molecular Architecture in Liquid Crystals

液晶的对称性和分子结构

• 批准号: 0345109
• 负责人: Charles Rosenblatt
• 金额: --
• 依托单位: Case Western Reserve University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0345109&HistoricalAwards=false
• 关键词: Symmetry; Molecular; Architecture; Liquid; Crystals

In this project, a new class of lamellar LC phases will be investigated, where the mesogens possess a side group that promotes formation of stacked lamellae (separated by the side groups). Lamellar versions of the isotropic, nematic, and smectic-A phases occur, with possibilities for many novel phenomena, including the ability to examine 3D to 2D crossover behavior. A second thrust involves mixtures of rigid bent-core (banana-shaped) and more flexible bi-mesogenic molecules in an ordinary calamitic liquid crystal host, which may give rise to biaxial nematic and smectic phases and provide important information on the anticlinic to synclinic transition. A third thrust involves polarizations that arise when a chiral molecule is in contact with, and tilted with respect to, an interface; the behavior of the ensuing polarization is very different from that found in the bulk Smectic-C* phase, and provides useful information on surface ordering. Student training is a significant component of the proposed work, which will enhance America's technological infrastructure. Students trained under this grant will be very competitive in the R&D job markets at laboratories such as IBM, Motorola, and Rockwell Corp.%%%Highly symmetric objects, such as spheres, have certain physical properties that less symmetric objects, such as curved cylinders do not have - and vice versa. Thus, when the symmetry of a liquid crystal is reduced, many scientifically fascinating and technologically useful phenomena arise. For example, fast electrooptic switching may occur, with myriad uses such as optical shutters, superfast displays, and optical computing. Reduced symmetry also may affect the nature of the phase transitions, and a complex liquid crystal molecule may form new phases. The purpose of the proposed work is to investigate new effects associated with reduced symmetry. The Principal Investigator and his students are utilizing a wide variety of sophisticated experimental tools, and several new and enigmatic phenomena will be examined and elucidated. Three topics will be studied: a new class of lamellar liquid crystalline phases; mixtures of rigid and semi-rigid banana-shaped molecules dissolved in an ordinary calamitic liquid crystal host; and polarizations that arise when a chiral molecule is in contact with, and tilted with respect to, an interface. The work will lead to new paths of scientific inquiry and may lead to the development of new technologies. Student training is a significant component of the proposed work, and an important outcome will be the enhancement of the country's technological infrastructure, as the supported students will be very competitive in the R&D job markets at labs such as IBM, Motorola, and Rockwell Corp.***

在这个项目中，将研究一类新的层状液晶相，其中介晶具有侧基，促进形成堆叠的层状（由侧基分开）。 层状版本的各向同性，双相和近晶-A相的发生，与许多新的现象，包括检查3D到2D交叉行为的能力的可能性。 第二个推力涉及在一个普通的棒状液晶主机，这可能会引起双轴向列和近晶相的刚性双核心（香蕉形）和更灵活的双介晶分子的混合物，并提供了重要的信息的背斜向向斜过渡。 第三个推力涉及极化时出现的手性分子是在接触，并相对于，界面倾斜;随之而来的极化行为是非常不同的，发现在体近晶-C * 相，并提供了有用的信息表面排序。 学生培训是拟议工作的一个重要组成部分，这将加强美国的技术基础设施。在这项资助下培训的学生将在IBM、摩托罗拉和罗克韦尔公司等实验室的研发就业市场上非常有竞争力。高度对称的物体，如球体，具有某些不对称的物体（如弯曲的圆柱体）所不具有的物理特性，反之亦然。 因此，当液晶的对称性降低时，就会出现许多科学上令人着迷和技术上有用的现象。 例如，可以发生快速电光切换，具有无数用途，诸如光学快门、超快显示器和光学计算。 降低的对称性也可以影响相变的性质，并且复杂的液晶分子可以形成新的相。 拟议的工作的目的是调查新的影响与减少对称性。 首席研究员和他的学生正在利用各种各样的复杂的实验工具，和几个新的和神秘的现象将被检查和阐明。 将研究三个专题：一类新的层状液晶相;溶解在普通棒状液晶主体中的刚性和半刚性香蕉形分子的混合物;以及当手性分子与界面接触并相对于界面倾斜时出现的偏振。 这项工作将为科学探索开辟新的道路，并可能导致新技术的发展。 学生培训是拟议工作的一个重要组成部分，一个重要的成果将是加强该国的技术基础设施，因为受资助的学生将在IBM、摩托罗拉和罗克韦尔公司等实验室的研发就业市场上非常有竞争力。