Soft matter physics of polymer-based materials and proteins

控制合成聚合物或天然蛋白质与小颗粒或结构之间微观相互作用的能力最终可能导致新材料的开发，这些材料具有特定应用的特性，或改善疾病的治疗或预防。我的研究计划的目标是了解这些小规模的聚合物相互作用在某些聚合物为基础的流体和生物系统。在人造材料中，聚合物和添加的纳米颗粒之间的相互作用会影响聚合物的移动方式，进而改变聚合物的整体性能，如流动性能、弹性和导电性。我们将对表征良好的聚合物-纳米颗粒复合材料和聚合物凝胶进行机械、电学和光学实验，以了解纳米颗粒和表面如何影响聚合物链的动力学和材料性能。有些材料（例如，发胶）在某些条件下是固体状的，但当施加的力克服了小规模的聚合物相互作用时，它们就会流动。我们将使用机械和光学测量来研究这些材料开始流动的过程的大尺度和小尺度特征。更好地了解这一过程的基本原理，可以改善工业流程的优化。在生命系统中，蛋白质和微观生物矿物晶体之间的相互作用控制着骨骼、牙齿和肾结石的生长。我们将通过使用激光散射来测量在蛋白质或肽存在下沉淀矿物晶体的大小来研究这是如何工作的。人们认为，蛋白质和免疫系统细胞（即巨噬细胞）膜上的小尺度结构之间的相互作用影响了它们摧毁病原体的能力。我们将通过研究细胞膜中蛋白质的运动和测量巨噬细胞在操纵膜结构时产生的力来了解巨噬细胞如何对病原体施加力。这些实验的结果将提高我们对这些重要生物学过程中涉及的生物物理学的理解。最后，我们将开发新的仪器和技术来测量含有聚合物和纳米颗粒的流体的粘弹性行为。虽然我对所有这些问题的方法都是基于物理的，但许多拟议的研究都是跨学科和协作的。参与这项研究的本科生、研究生和博士后研究人员将使用最先进的仪器和技术。总的来说，这项创新研究将为我们提供对纳米级聚合物相互作用更好的基础理解，并将在材料科学、流体动力学和微生物学等不同领域产生影响。

The ability to control the microscopic interactions between synthetic polymers or naturally-occurring proteins and small particles or structures could ultimately lead to the development of new materials with properties tuned for particular applications, or to improved treatment or prevention of diseases. The goal of my research program is to understand these small-scale polymer interactions in certain polymer-based fluids and biological systems. In man-made materials, interactions between polymers and added nanoparticles affect the way the polymers can move, which in turn modifies bulk properties such as flow behavior, elasticity, and electrical conductivity. We will perform mechanical, electrical, and optical experiments on well-characterized polymer-nanoparticle composite materials and polymer gels to learn how nanoparticles and surfaces affect the dynamics of the polymer chains and material properties. Some materials (e.g., hair gel) are solid-like under some conditions, but flow when the small-scale polymer interactions are overcome by an applied force. We will use mechanical and optical measurements to investigate the large- and small-scale features of the process by which these materials start to flow. Better fundamental understanding of this process could lead to improved optimization of industrial flows. In living systems, interactions between proteins and microscopic biomineral crystals control the growth of bone, teeth, and kidney stones. We will investigate how this works by using laser light scattering to measure the size of precipitating mineral crystals in the presence of proteins or peptides. It is believed that interactions between proteins and small-scale structure in the membrane of immune-system cells known as macrophages affect their ability to destroy pathogens. We will learn how macrophages exert forces on pathogens by studying the motion of proteins in the cell membrane and measuring the forces generated by macrophages as we manipulate the membrane structure. Results from these experiments will improve our understanding of the biophysics involved in these biologically important processes. Finally, we will develop new instruments and techniques for measuring the viscoelastic behavior of fluids containing polymers and nanoparticles. While my approach to all of these problems is physics-based, much of the proposed research is interdisciplinary and collaborative. The undergraduates, graduate students, and postdoctoral researchers who will contribute to this research will use state-of-the-art instruments and techniques. Overall, this innovative research will provide us with a better fundamental understanding of nanoscale polymer interactions and will have impact in fields as diverse as materials science, fluid dynamics, and microbiology.