Novel Dynamics in Complex Fluids: From Phonons to the Drying Process

****技术摘要****本实验程序探索复杂流体的基本性质。复杂流体是指诸如颗粒悬浮液、乳液、油水界面、聚合物和表面活性剂溶液、液晶及其混合物等材料。所提出的实验的一个统一特征是它们关注复杂流体中的动力学。一组实验将测量有缺陷的胶体晶体和胶体玻璃的振动特性，着眼于阐明这些材料内部局部振动和内部重排之间的联系，特别是在没有外部应力的情况下。第二组实验将研究与干燥胶体滴的颗粒形状和界面相互作用有关的影响。这项工作建立在最近发现的基础上，即悬浮颗粒的几何形状可以用来消除著名的咖啡环效应；我们将进行实验来了解这些系统中出现的新型弹性膜的性质，即通过空气-水表面颗粒的吸附和相互作用。软质材料在油漆、食品科学、化妆品工业、流体流变学和微流体的实际控制、细胞生物学、高科技问题如光子学、印刷和光刻、生化传感和复合材料设计等方面都有应用。所获得的知识将增强我们在溶液中操纵微/纳米粒子和大分子的能力，为上面列出的实际问题提供见解。该项目培养软性材料科学、光学显微镜和显微操作技术方面的博士生和博士后。反过来，这些学生和博士后将离开宾夕法尼亚大学，加强我们国家的技术基础设施。****非技术摘要****复杂流体是指胶体悬浮液、乳液、油水界面、聚合物和表面活性剂溶液、液晶及其混合物等材料。这些软材料在油漆、食品科学、化妆品工业、流体流变学和微流体的实际控制、细胞生物学、高科技问题（如光子学、印刷光刻、生化传感和复合材料设计）中得到了应用。复杂流体研究阐明了广泛的现象：探测玻璃中的振动，探索玻璃内部重排的起源，以及研究颗粒形状和界面变形在影响干燥过程中的作用。在这些研究中获得的知识将增强我们在溶液中操纵大分子的能力，为上面列出的许多实际问题提供见解。作为这项研究的一部分开发的技术已经导致两家纳米技术公司的成立，并与一家更大的化学公司进行了重大合作。该项目还教授新一代的博士/博士后科学家和工程师关于软材料和光学显微镜和显微操作。在这里完成工作后，这些学生和博士后加强了我们国家的技术和经济基础设施。

****Technical Abstract****This experimental program explores fundamental properties of complex fluids. Complex fluids are materials such as particle suspensions, emulsions, oil-water interfaces, polymer & surfactant solutions, liquid crystals, and mixtures thereof. A unifying feature of the proposed experiments is their focus on dynamics in complex fluids. One set of experiments will measure the vibrational properties of colloidal crystals with defects and in colloidal glasses & gels, with an eye towards elucidating connections between localized vibrations and internal rearrangements within these materials, especially in the absence of external stresses. A second set of experiments will investigate the effects associated with particle shape and interfacial interactions in drying colloidal drops. This work builds on the recent discovery that the geometric shape of suspended particles can be used to eliminate the famous coffee ring effect; we will carry out experiments to understand the nature of the novel elastic membranes that arise in these systems, i.e., via adsorption and interaction of the particles on the air-water surface. Soft materials find applications in the paint, food science, & cosmetics industries, in practical control of fluid rheologies & microfluidics, in cell biology, in high-tech problems such as photonics, printing & lithography, biochemical sensing, and in design of composites. Knowledge gained will enhance our ability to manipulate micro-/nano-particles and macromolecules in solution, providing insight for practical problems listed above. The program trains PhD students and post-docs in the science of soft materials and the technology of optical microscopy & micromanipulation; these students and post-docs, in turn, will leave Penn and strengthen the technological infrastructure of our nation.****Non-Technical Abstract****Complex fluids are materials such as colloidal suspensions, emulsions, oil-water interfaces, polymer & surfactant solutions, liquid crystals, and mixtures thereof. These soft materials find applications in the paint, food science, & cosmetics industries, in practical control of fluid rheologies & microfluidics, in cell biology, in high-tech problems such as photonics, printing & lithography, biochemical sensing, and in design of composites. The complex fluid research elucidates a wide-range of phenomena: probing vibrations in glasses, exploring the origin of internal rearrangements in glasses, and investigating the role of particle shape and interface deformation in affecting drying processes. Knowledge gained in these studies will enhance our ability to manipulate macromolecules in solution, providing insight for the many of the practical problems listed above. Technology developed as part of this research has led to the formation of two start-up nanotechnology companies and to a major collaboration with a larger chemical company. The program also teaches a new generation of PhD/post-doctoral scientists and engineers about soft materials and optical microscopy & micromanipulation; after finishing work here, these students and post-docs strengthen the technological and economic infrastructure of our nation.