Elasticity, Deformation, Rearrangement & Assembly in Complex Fluids

摘要本文提出的实验研究将对两大科学技术领域产生影响：如何制造更坚固的材料和如何将液晶显示技术的思想应用于新的水基液晶系统。广泛地说，该计划开发了新的能力，制定和操纵微和纳米粒子和溶液中的大分子。因此，这项研究增强了科技企业的实力，为美国传感/驱动、微流体、药物输送、光子学、印刷、涂料、化妆品和农业等行业的应用奠定了基础。该项目将培养软材料、配方、先进光学显微镜、电光学、微流体、流变学和计算等领域的新一代科学家和工程师。完成学业后，博士生和博士后进入劳动力市场，加强美国的技术和经济基础设施；此外，每年夏天，我们的实验室都会刺激不同群体的本科生和高中生进行STEM教育/职业选择。技术摘要：该计划旨在提高对复杂流体和软材料的认识，但许多发现也将引起硬凝聚态物质，化学工程和材料科学界的兴趣。提出的实验是统一的，他们的重点是微观力学，广义的定义。一组将测量胶体玻璃和晶体的结构和动力学特性，目的是确定这些材料中“柔软”的区域，并表现出变形或重新排列的增加倾向。第二组将研究溶致变色液晶。这些液晶的不寻常之处在于它们很容易扭曲，从而导致从非手性介质形成手性结构，它们表现出从分子到棒状介质到LC相的两级组装层次，并且它们是水溶性的。这些性质的结果将通过扩散实验来探索，扩散实验跟踪局部LC导向场修饰的粒子运动，通过研究“极端”受限几何形状中弹性能和分子组装层次之间的竞争，以及在多相液滴的新型“干燥”中。总的来说，实验使用先进的光学显微镜、光散射和流变学来观察样品，他们需要通过控制悬浮化学和物理、微流体等来制定新的软材料。例如，具有不同形状、相互作用和原位操作潜力的胶体颗粒正在/将被开发。

Non-technical AbstractThe proposed experimental research will have impact in two major science and technology arenas: how to make a tougher material and how to adapt ideas of liquid crystal display technology to new water-based liquid crystal systems. Broadly, the program develops new ability to formulate and manipulate micro- and nano-particles and macromolecules in solution. Thus the research enhances the science and technology enterprise that underpins applications efforts for US industries involved with sensing/actuation, microfluidics, drug delivery, photonics, printing, coatings, cosmetics and agriculture. The program will train a new generation of scientists and engineers in soft materials, formulation, advanced optical microscopy, electro-optics, microfluidics, rheology & computation. After finishing, PhD students & post-docs enter the work force and strengthen US technological and economic infrastructure; furthermore, a diverse group of undergraduate and high school participants are typically stimulated every summer in our laboratory to pursue STEM education/career choices.Technical AbstractThe proposed program aims to advance knowledge about complex fluids and soft materials, but many findings will also interest the hard condensed matter, chemical engineering and materials science communities. The proposed experiments are unified by their focus on micro-mechanics, broadly defined. One set will measure structural and dynamical properties of colloidal glasses and crystals with goals to identify regions within these materials that are "soft" and exhibit increased propensity to deform or rearrange. A second set will investigate lyotropic chromonic liquid crystals. These liquid crystals are unusual in that they twist very easily which leads to formation of chiral structures from achiral mesogens, they exhibit two levels of assembly hierarchy from molecules to rod-mesogens to LC phases, and they are water soluble. The consequences of these properties will be probed by diffusion experiments which track motions of particles dressed by local LC director fields, by study of the competition between elastic energy and molecular assembly hierarchy in "extreme" confined geometries, and in novel "drying" of multi-phase droplets. Collectively, the experiments use advanced optical microscopies, light scattering and rheometry for sample observation, and they require formulation of novel soft materials via controlled suspension chemistry and physics, microfluidics, etc. For example, colloidal particles with different shapes, interactions and potential for in-situ manipulation are/will-be developed.