Microscopic dynamics of soft systems

我通过观察材料的微观动力学来开发提取材料信息的新方法。我对这样做特别感兴趣的是，除了了解这些系统如何移动之外，还了解它们如何组织和传播压力。这种洞察力对于帮助物理学家理解软材料和复杂流体（如生物细胞的支架）非常重要，而这种基本的理解正是我的动力所在。当然，这种理解也可以帮助从食品科学到生物技术和生物医学的一系列应用。在这个建议中，我描述了我计划如何使用我的实验室出来的技术，以推动我们的理解的方式，其中微观结构和动力学决定的相行为和宏观动力学性质在硬球和弱吸引力的领域冻结和玻璃形成后，即固化。为了做到这一点，我将使用一个键长可以控制的胶体模型系统，这样我就可以研究作为键长函数的各种固相，从而在同一模型系统中直接观察一些基本物理，而在原子系统中则无法观察到。我建议使用的物理内容的热运动的微米大小的探针粒子，使用一种技术称为微流变学，揭示机械和材料信息的肌动蛋白微管为基础的模型的细胞骨架。这一拟议的工作建立在我在这两个领域的既定工作基础上，推动了新的基本方法，导致对重要的硬球模型系统的新见解，以及对冷冻、玻璃形成、细胞设计原理、生物聚合物物理学以及微观流变学方法本身的普遍性的更深入理解。

I develop new ways of extracting information about materials by observation of their microscopic dynamics. My particular interest in doing this is to gain insight regarding how these systems organize and propagate stress, in addition to how they move about. Such insight is of extraordinary importance in helping physicists understand soft materials and complex fluids such as the scaffolding of biological cells, and that fundamental understanding is what motivates me. Of course, such understandings can also assist a whole array of applications, from food science, to biotechnology and to biomedicine. In this proposal I describe how I plan to use the techniques coming out of my lab to push forward our understanding of the way in which microscopic structure and dynamics determine the phase behaviour and macroscopic dynamical properties in hard spheres and weakly attractive spheres upon freezing and glass formation-that is, upon solidification. To do this I will use a colloid model system in which the bond length can be controlled, so that I may investigate various solid phases as a function of the bond length, and thereby directly observe some fundamental physics in the same model system in ways we cannot in atomic systems. I propose to use the physical content of thermal motions of micrometer-sized probe particles, using a technique called microrheology, to reveal mechanical and material information about an actin-microtubule based model for the cell cytoskeleton. This proposed body of work builds on my established work in both these areas, pushing in new fundamental ways that lead to novel insights about the important hard sphere model system, and a deeper understanding of freezing, glass formation, the design principles of the cell, the physics of biopolymers, and the generality of the microrheology method itself.