Symmetry, Epitaxy and Ordering Processes of Supramolecular Assemblies

9806684哈德逊将研究一些新的合成液晶材料，这些材料形成类似于某些生物材料的球形或圆柱形纳米结构(超分子组件)。选择热致材料进行这项研究，是因为它的优点包括实验简单性和在恶劣环境(温度或真空)、电子和多功能复合材料中的固有应用。这些材料的电子应用潜力是显而易见的：具有最快电荷传输的有机光导体按照柱状组装和液晶排列的原则工作。有序-有序转变(例如，从柱状到球状)已经确定，并将用衍射和电子显微镜进行研究。它们既可以由温度变化引起，也可以由聚合引起。对这些转变的研究将提供对每一相的结构和稳定性的重要理解。通过与PI的几次合作，提供了一系列同源分子，从而确定了分子结构对超分子形状和堆积的影响。长链和短链分子链之间的异同将被阐明。这些知识将为发展有关小的两亲分子相行为的理论概念提供有用的输入。通过对这些材料的有序-无序转变的研究，将获得对这些材料的进一步洞察。利用流变性蚂蚁光学分析，这个项目将研究各向同性到柱状的相变，以及过渡前涨落的存在，这将表明无序状态中存在柱状结构。这种有序转变的控制对于器件性能依赖于列取向的应用是至关重要的。将探索这些材料的表面锚定和流动对齐。该项目将为研究生提供指导和培训。这个项目还将使实验室课程的自我指导部分受益(研究生和本科生水平)。自然界中%的功能纳米结构(用于信息存储、化学物质和能源的选择性传输以及机械强度和韧性)启发了合成材料的发展。本项目将研究合成的无溶剂液晶纳米结构的结构和有序化过程，这些纳米结构更适合于在苛刻的环境(如高温或真空)、光电子和多功能复合材料中应用。这项工作将与其他实验室的合成工作并行进行，以便确定分子设计的原则。***

9806684 Hudson A number of new synthetic liquid crystalline materials that form spherical or cylindrical nanostructures (supramolecular assemblies) that are similar to certain biological materials will be investigated. Thermotropic materials are selected for this study, because of benefits that include experimental ease snd inherent application to harsh environments (temperature or vacuum), electronic and multifuntional ccomposite materials. The potential for electronic application of these materials is clear: the organic photoconductors with the most rapid charge transport operate on the principles of columnar assembly and liquid crystalline alignment. Order-order transitions (e.g. from columnar to spheroidal) have been identified and will be studied by diffraction and electron microscopy. These can be induced either by a temperature changeor by polymerization. Investigation of these transitions will provide significant understanding of thestructure and stability of each phase. Homologous series of molecules are being provided through several collaborations with the PI, so that the influence of molecular architecture on supramolecular shape and packing will be determined. The similarities and differences between long and short chain molocuhs will be elucidated. Such knowledge will be useful input for the development of theoretical concepts concerning the phase behavior of small amphiphiles. Further insight into these materials will be gained through the study of their order-disorder transitions. Using rheological ant optical analysis, this project will investigate the isotropic-to- columnar phase transition and the existence of pretransitional fluctuations that would indicate the presence of columns within the disordered state. The contol of this ordering transition is crucial for applicafions in which the device performance depends on column orientation. Surface anchoring and flow alignment of these materials will be explored. This project w fll provide the instruction and training of a graduate student. This project will also benefit a self directed portion of a laboratory course (at the graduate and undergraduate level). %%% Functional nanostructures in Nature (used for information storage, selective transport of chemicals and energy, and mechanical strength and toughness) inspire synthetic materials development. This project will investigatc the structure and ordering processes of synthetic solvent-free liquid crystalline nanostructures that are more suited to application in demanding environments (such as high temperature or vacuum), photoelectronic and multifunctional composite materials. This work will proceed in parallel with synthetic efforts in other labs so that principles of molecular design can be determined. ***