Theory of nonuniform complex liquids

非均匀复杂液体理论

• 批准号: 3445-2008
• 负责人: Sullivan, Donald
• 金额: $ 1.78万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2009
• 资助国家: 加拿大
• 起止时间: 2009-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=419719
• 关键词: Theory; nonuniform; complex; liquids

Most of the proposed research topics are extensions of ones which I have recently studied in the theory of polymeric liquid crystals (PLC). These materials are important due to their many applications, such as to LC display devices, nanolithography, and biological structures. My recent research has examined two complementary athermal models of the polymer chains, one based on a discrete microscopic model consisting of bonded hard-sphere chains, the other employing a continuum "wormlike-chain" representation of the molecules. In both models, excluded-volume interactions between the molecules which lead to liquid-crystalline ordering are taken into account by means of the Onsager second-virial approximation. A main focus has been to study smectic liquid-crystalline phases of these models, which have a layered morphology similar to that of lipid vesicles, and to understand the interplay between the interactions and the degree of molecular flexibility in the formation of these phases. We are also interested in the effects of a confined geometry on the phase boundaries, which is relevant to systems such as DNA confined within viruses. A variant of the work on confined systems has been concerned with the behaviour of free-standing smectic films, in particular the phenomena of layer-thinning transitions. The proposed research will extend my recent studies in the following ways: (1) revision of the numerical algorithms for solving both the wormlike-chain and the hard-sphere chain models, in order to apply these to molecules with physically realistic length-to-width ratios; (2) extension of our studies of confined systems (so far limited to liquids trapped between flat parallel walls) to other geometries, such as cylinders and spheres; (3) studies of the dynamics of layer-thinning transitions for films having 1st-order isotropic-smectic phase transitions. Mixed with these topics, we will also study various fundamental aspects such as the nature of boundary conditions at a wall, inclusion of high-density effects, and "self-interactions" between polymer chains in the wormlike model.

大多数提出的研究课题都是我最近在聚合液晶（PLC）理论中研究的课题的延伸。这些材料因其许多应用而非常重要，例如液晶显示设备、纳米光刻和生物结构。我最近的研究检查了聚合物链的两种互补的无热模型，一种基于由键合硬球链组成的离散微观模型，另一种采用分子的连续“蠕虫状链”表示。在这两个模型中，通过 Onsager 第二维里近似考虑了导致液晶有序的分子之间的排除体积相互作用。主要重点是研究这些模型的近晶液晶相，其具有与脂质囊泡相似的层状形态，并了解这些相形成过程中相互作用和分子柔性程度之间的相互作用。我们还对受限几何形状对相界的影响感兴趣，这与限制在病毒内的 DNA 等系统相关。受限系统工作的一个变体涉及独立近晶薄膜的行为，特别是层薄化转变的现象。拟议的研究将通过以下方式扩展我最近的研究：（1）修订用于求解蠕虫链和硬球链模型的数值算法，以便将这些算法应用于具有物理真实长度的分子。宽度比； (2) 将我们对受限系统的研究（到目前为止仅限于平坦平行壁之间的液体）扩展到其他几何形状，例如圆柱体和球体； (3) 研究具有一阶各向同性-近晶相变的薄膜的层减薄转变动力学。与这些主题相结合，我们还将研究各种基本方面，例如壁边界条件的性质、高密度效应的包含以及蠕虫模型中聚合物链之间的“自相互作用”。