Temperature-Sensitive 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、乳液、聚合物和表面活性剂溶液、液晶及其混合物。这些软材料应用于涂料、食品科学和化妆品行业、流体流动和微流体的实际控制、细胞和组织生物学，以及需要新的材料设计和加工方法的高科技问题，如光子学、光刻和生化传感器。具体地说，这项研究将创造新的材料来阐明各种基本现象，如熔化、结晶、堵塞、受挫和其他类别的自组装。所获得的知识将提高我们直接观察和操纵微米和纳米粒子，以及更广泛地说，溶液中的大分子的能力。这项研究反过来为上述实际问题提供了洞察力。作为这项研究的一部分开发的技术具有潜在的经济效益，例如，它导致了两家初创纳米技术公司的成立，以及与总部设在宾夕法尼亚州的一家规模更大的公司的广泛合作。该项目还将教育新一代科学家和工程师有关软材料和光学技术的知识；这些学生和博士后将加强国家的技术基础设施。*技术摘要*本计划建议对复杂的流体进行实验，以阐明熔化和自组装等效应。复合流体是软材料，包括胶体悬浮液、乳状液、聚合物和表面活性剂溶液、液晶及其混合物。这些软材料在各种日常产品中都有应用。例如油漆、食品和化妆品；软材料的概念也被证明有助于理解细胞和组织生物学，并有助于开发光子学、光刻和生化传感方面的高科技材料。本计划的一个统一特点是创造和使用基于温度敏感型聚合物的小颗粒。这些颗粒对温度等环境刺激做出反应时会膨胀和收缩，从而使实验人员能够诱导相变，然后可以通过光学显微镜和散射技术进行原位研究。这项研究将阐明广泛的现象，包括几何受挫、二维、三维和几层膜中的熔化机制、堵塞以及管内粒子的手性不稳定性。该项目将培训新一代软材料、光学显微镜和微操作方面的科学家和工程师，所获得的知识将教会我们操作溶液中的微米和纳米粒子，从而为我们提供对上面列出的实际问题的洞察。

****NON-TECHNICAL ABSTRACT****This experimental program will explore the fundamental properties of complex fluids such as colloidal suspensions, emulsions, 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 flow and micro-fluidics, in cell & tissue biology, and in high-technology problems such as photonics, lithography, biochemical sensors which require new approaches to materials design and processing. Specifically, the research will create new materials to elucidate a variety of basic phenomena such as melting, crystallization, jamming, frustration and other classes of self-assembly. Knowledge gained will improve our ability to directly observe and manipulate micro- and nano-particles and, more generally, macromolecules in solution. This research, in turn, offers insight for the practical problems listed above. Technology developed as part of this research has potential economic benefit, e.g. it has led to the formation of two start-up nanotechnology companies as well as a broad collaboration with a much larger company based in PA. The program will also educate a new generation of scientists and engineers about soft materials and about optical techniques; these students and post-docs strengthen the technological infrastructure of the nation. ****TECHNICAL ABSTRACT****This program proposes experiments on complex fluids to elucidate effects such as melting and self-assembly. Complex fluids are soft materials including colloidal suspensions, emulsions, polymer & surfactant solutions, liquid crystals, and mixtures thereof. These soft materials find applications in a variety of ?everyday products? such as the paint, food and cosmetics; soft materials concepts are also proving to be useful for understanding cell & tissue biology, and for developing high-technology materials in photonics, lithography and biochemical sensing. A unifying feature of the present program is the creation and use of small particles based on temperature-sensitive polymers. These particles swell and contract in response to environmental stimuli such as temperature, and thereby enable experimenters to induce phase transformations that can then be studied in-situ by optical microscopy and scattering techniques. The research will elucidate a wide-range of phenomena including geometric frustration, melting mechanisms in two- and three-dimensions and in few-layer films, jamming, and the chiral instabilities of particles in ?tubes?. The program will train a new generation of scientists and engineers about soft materials, optical microscopy and micromanipulation, and the knowledge gained will teach us to manipulate micro- and nano-particles in solution, thereby offering insight into the practical problems listed above.