Theory of Liquid Crystals and Related Materials

DMR-9730405 Lubensky液晶是具有与液体相关的流动能力等性质和与结晶固体相关的光学各向异性等性质的材料。 新的液晶材料，熟悉相的新实现，甚至全新的液晶相不断被发现。 在这个补助金的理论研究将进行两个一般方面的物理液晶：手性和层状结构。 介晶的手性反映在丰富多样的平衡相中，所述平衡相包括介晶相、蓝相、铁电近晶-C * 相以及A和C扭曲晶界相。本研究试图阐明这些相的结构手性和手性之间的关系在微观水平上。将研究的其他问题，是与手性包括：在柱状相的手性结构，手性路径从α-近晶-A相，和相变扭曲晶界C相。 研究的一个主要部分将致力于研究由插入脂质双层之间的DNA片段形成的2D近晶晶格。 库仑力导致相邻层中晶格之间的相互作用。这些结构在基因治疗研究中很重要。 拟议的研究的一个主要重点将是研究这些复合物的统计和结构特性。 将探索用于这些相的模型，所述模型在一维近晶相和二维柱状相之间插值，并且显示出预测新的平衡相的希望，所述新的平衡相的特征在于2D DNA晶格之间的取向相关性而不是位置相关性。 还将研究由独立的近晶薄膜所表现出的相。 %液晶是具有与液体相关的性质（例如流动能力）和与结晶固体相关的性质（例如光学各向异性）的材料。 新的液晶材料，熟悉相的新实现，甚至全新的液晶相不断被发现。 Lubensky将继续他的理论研究，与实验密切联系，进入传统和新颖的新液晶材料。 这项研究的一个中心主题涉及调查这些材料中出现的许多丰富多样的相，以及基本对称性如何影响观察到的相的宏观性质，例如分子是否可以叠加在其镜像上，以及分子水平上的性质。特别感兴趣的是涉及在基因治疗研究中起主要作用的DNA片段的新相以及相如何响应于外部施加的电场。这项研究还将有助于培训这些技术上有前途的材料的下一代专家。 ***

DMR-9730405 Lubensky Liquid crystals are materials that possess properties, such as the ability to flow, associated with liquids, and properties, such as optical anisotropy, associated with crystalline solids. New liquid crystalline materials, new realizations of familiar phases, and even entirely new liquid crystalline phases are continually being discovered. In this grant theoretical research will be carried out on two general aspects of the physics of liquid crystals: chirality and layered structures. Chirality of the mesogens is reflected in a rich variety of equilibrium phases that include the cholesteric phase, the blue phases, ferroelectric smectic-C* phase, and the A and C twisted grain boundary phases. This research seeks to elucidate the relationship between the structural chirality of these phases and chirality at a microscopic level. Other problems that will be studied that are related to chirality include: chiral structures in columnar phases, chiral pathways from the nematic to smectic-A phase, and phase transitions to the twisted grain boundary C phase. A major part of the reseach will be devoted to the study of 2D smectic lattices that form from DNA segments that are intercalated between lipid bilayers. Coulomb forces lead to interactions between lattices in adjacent layers. These structures are important in gene-therapy research. A major focus of the proposed research will be to study the statistical and structural properties of these complexes. Models for these phases that interpolate between one- dimensional smectic and two-dimensional columnar phases and show promise of predicting new equilibrium phases characterized by orientational but not positional correlations between 2D DNA lattices will be explored. Phases exhibited by free standing smectic films will also be studied. %%% Liquid crystals are materials that possess properties, such as the ability to flow, associated with liquids, and properties, such as optical anisotropy, as sociated with crystalline solids. New liquid crystalline materials, new realizations of familiar phases, and even entirely new liquid crystalline phases are continually being discovered. Lubensky will continue his theoretical inquiry, in close connection with experiments, into traditional and novel new liquid crystalline materials. A central theme of this research involves the investigation of many of the rich variety of phases that occur in these materials and how fundamental symmetries, such as whether or not a molecule can be superimposed on its mirror image, and properties at the molecular level, influence macroscopic properties of observed phases. Of particular interest are novel phases involving DNA segments that play a major role in gene- therapy research and how a phase responds to an externally applied electric field. This research will also contribute to the training of the next generation of experts in these technologically promising materials. ***