Interactions and Assembly in Suspension

这个实验凝聚态物理项目将探索复杂流体的基本特性，包括胶体悬浮液、乳液、聚合物溶液、膜及其混合物。这些“软”材料在油漆、食品科学和化妆品工业、流体流变学的实际控制、细胞生物学以及光子学、光刻、生化传感器和处理器等高科技问题中得到了应用。这项工作解决了悬架科学中的三个基本问题：(i)微观相互作用，（ii）组装，（iii）新的宏观模型系统。实验计划：(1)测量由大分子、囊泡和膜产生的悬浮液中的相互作用，通过微妙的水化效应，通过聚合物诱导的空间相互作用，以及通过偶极或各向异性背景流体；(2)利用偏向亚稳态生长的模板研究胶体晶体的平衡组装；(3)研究极高密度和极低密度（即低筛限）下棒和板的平衡相。(4)发展组装胶体晶体异质结构的方法。(5)合成新的悬浮液成分，使我们有可能创造新的宏观模型体系，例如宏观表面活性剂。在这些研究中获得的知识将提高我们对复杂流体中相互作用和组装的基本理解，并将导致控制组装和研究软材料微观相互作用的新技术。参与该项目的研究生接受基础前沿实验技术的培训，如显微镜、光学、应用计算和悬浮科学。这项培训将为学生和同事在工业、政府或学术界的职业生涯做好准备。这个实验凝聚态物理项目研究了一系列复杂流体的性质，即所谓的“软物质”。复杂流体包括胶体悬浮液、乳液、聚合物溶液、膜、液晶及其混合物。软质材料的结构和动力学受到无序（熵）和相对较弱的机械力（如触变性、粘滞）的强烈影响。这些材料为多体统计物理和相变（如熔化和凝固）的研究提供了一个迷人的试验场。对这些物质的研究也是由技术驱动的。它们是光子学、光刻、陶瓷和生化传感等高科技应用中有吸引力的起始材料；颗粒添加剂还提供了一种实际控制流体流动的手段，改善了传统材料（如油漆、机油、食品和化妆品）的性能。最后，复杂的流体实验越来越多地受到细胞生物学类比的刺激，在某些情况下，为拥挤的细胞环境中出现的机制提供了关键的见解。本研究主要集中在三个基本问题：悬浮液中微观力的测量，相变和自组装的研究，以及新的宏观模型系统的创建。该课程的学生接受光学、物理和材料科学方面的严格培训，为他们在学术界、工业界和政府部门的职业生涯做好准备。

This experimental condensed matter physics project will explore the fundamental properties of complex fluids, which include colloidal suspensions, emulsions, polymer solutions, membranes, and mixtures thereof. These "soft" materials find applications in the paint, food science, and cosmetic industries, in the practical control of fluid rheologies, in cell biology, and in high-tech problems of photonics, lithography, and biochemical sensors and processors. This work addresses three basic issues in suspension science:(i) Microscopic interactions, (ii) Assembly, and (iii) New macroscopic model systems. Experiments are planned to: (1) Measure interactions in suspension produced by macromolecules, vesicles, and membranes, by subtle hydration effects, by polymer-induced steric interactions, and by dipolar or anisotropic background fluids; (2) Study the equilibrium assembly of colloidal crystals with templates that bias growth towards metastable states; and (3) Study the equilibrium phases of rods and plates at very high densities, and at very low densities (i.e. in the low-screening limit). (4) Develop methodologies to assemble colloidal crystal heterostructures. (5) Synthesize new suspension constituents that offer us the possibility to create new macroscopic model systems, for example macroscopic surfactants. Knowledge gained in these studies will improve our fundamental understanding about interactions and assembly in complex fluids, and should lead to new techniques for controlling assembly and for studying microscopic interactions in soft materials. Graduate students involved in the project receive training in fundamental cutting edge experimental techniques such as microscopy, optics, applied computation, and suspension science. This training will prepare students and associates for careers in industry, government or academe. This experimental condensed matter physics project investigates the properties of a range of complex fluids, examples of so-called "soft matter". Complex fluids include colloidal suspensions, emulsions, polymer solutions, membranes, liquid crystals and mixtures thereof. The structure and dynamics of soft materials are strongly influenced by disorder (entropy) and by relatively weak mechanical forces (as in thixotropy, catsup). These materials provide a fascinating testing ground for many-body statistical physics, and for investigations of phase transitions such as melting and solidification. Research on these substances is technology driven too. They are attractive starting materials in high-tech applications such as photonics, lithography, ceramics and biochemical sensing; particle additives also offer a means for practical control of fluid flow, improving the performances of conventional materials such as paints, motor oils, foods, and cosmetics. Finally, complex fluids experiments are increasingly stimulated by analogies from cell biology, in some cases providing critical insights about mechanisms that arise in crowded cellular environments. This research focuses on three basic issues: measurement of microscopic forces in suspension, the study of phase transitions and self-assembly, and the creation of exotic new macroscopic model systems. Students in this program receive rigorous training in optics, physics, and materials science that prepares them for careers in academe, industry, and government.