Structure and Dynamics in Temperature-Sensitive and Anistropic Complex Fluids

*非技术摘要*本实验计划将探索复杂流体的基本性质，如胶体悬浮液、乳状液和油水界面、聚合物和表面活性剂溶液、液晶及其混合物。这些软材料在涂料、食品科学和化妆品工业、流体流变性和微流体的实际控制、细胞生物学、光子学、光刻、生化传感器和处理器等高科技问题以及先进复合材料的设计中得到应用。这个项目将创造新的材料，并将阐明各种基本现象，如熔化、扩散和自组装。在这些研究中获得的知识将影响我们操纵溶液中的粒子(微米和纳米粒子)和大分子的能力，从而为上面列出的实际问题提供洞察。作为这项研究的一部分而开发的技术具有潜在的经济效益，例如，它已经导致了一家初创的纳米技术公司的成立。该项目还将教育新一代科学家和工程师有关软材料的知识；这些学生将为国家的技术基础设施做出贡献。*技术摘要*这个个人研究人员奖支持软材料的实验，以阐明使用非传统材料和观察工具进行熔化、扩散和自组装等传统现象。这项研究还将创造和理解各种新型的“超复杂流体”的行为，即由多种软材料组成的复杂流体。该项目包括三组实验：1)将使用温度敏感型聚合物来诱导新的相行为，并能够在一系列复杂流体中原位观察相变动力学和结垢。这项研究的重点将集中在温度敏感型溶致胶体的熔融、冻结、固-固相变和堵塞。2)研究各向同性和各向异性介观粒子(例如球形和椭圆形粒子)在向列相液体和二维界面等特殊背景溶剂中的扩散和结构。3)研究了单壁碳纳米管(SWNTs)与各种软材料混合形成的新型复合流体材料和唯象。初步研究已经发现了大量的复杂流体(如表面活性剂溶液、凝胶、环氧体)，其性质(如流变性、电性)因添加单壁碳纳米管而发生显著变化。对这一系统类的调查将从基本的角度出发。此外，还将确定操纵纳米管的新方法。参与这些研究项目的学生将学到一些技能，这些技能将为国家的技术基础设施增添力量。

**** NON-TECHNICAL ABSTRACT ***This experimental program will explore the fundamental properties of complex fluids such as colloidal suspensions, emulsions and oil-water interfaces, polymer and surfactant solutions, liquid crystals, and mixtures thereof. These soft materials find applications in the paint, food science, and cosmetics industries, in the practical control of fluid rheologies and microfluidics, in cell biology, in high-tech problems such as photonics, lithography, biochemical sensors and processors, and in design of advanced composites. This project will create new materials and will elucidate a variety of basic phenomena such as melting, diffusion, and self-assembly. Knowledge gained in these studies will impact on our ability to manipulate particles (micro- and nano-particles) and macromolecules in solution, and thereby offer insight for the practical problems listed above. Technology developed as part of this research has potential economic benefit, e.g. it has led already to the formation of a start-up nanotechnology company. The program will also educate a new generation of scientists and engineers about soft materials; these students will add to the technological infrastructure of the nation. **** TECHNICAL ABSTRACT ****This individual investigator award supports experiments in soft materials to elucidate traditional phenomena such as melting, diffusion and self-assembly using non-traditional materials and observational tools. The research will also create and understand the behavior of a variety of novel 'hyper-complex fluids', i.e. complex fluids composed of more than one soft material. The project involves three sets of experiments; 1) Temperature-sensitive polymers will be employed to induce novel phase behavior, and to enable in-situ observations of phase transition dynamics and scaling in a range of complex fluids. The focus of this study will be on melting, freezing, solid-solid phase transitions, and jamming of temperature-sensitive lyotropic colloids. 2) Diffusion and structure of isotropic and anisotropic mesogens (e.g. spherical and ellipsoidal particles) in unusual background solvents such as nematic liquids and two-dimensional interfaces will be investigated. 3) New complex fluid materials and phenomenology created by mixing single-wall carbon nanotubes (SWNTs) in various soft materials will be studied. Preliminary studies have identified a plethora of complex fluids (e.g. surfactant solutions, gels, epoxies) whose properties (e.g. rheological, electrical) are dramatically changed by addition of SWNTs. Investigation of this system class will be from a fundamental viewpoint. In addition new methodologies for manipulation of nanotubes will be identified. The students involved in these research projects will learn skills that will add to the technological infrastructure of the nation.