Structure and Diffusive Motion in Confined Multi-component Colloid Suspensions

Stuart Rice获得了化学部门实验物理化学项目的资助，对准二维系统的性质进行实验和理论研究。所研究的系统是非常薄的细胞中不带电的单分散胶体颗粒的悬浮液。实验研究主要基于数字视频显微镜测量和图像分析，而理论工具包括计算机模拟、统计力学和流体力学。需要解决的具体问题包括：1)直接（非流体动力）胶体-胶体相互作用的范围和强度与约束尺度之间的相互作用对致密胶体悬浮液所能支持的相结构的影响；2)胶体-胶体直接相互作用、悬浮液中流体动力相互作用和约束尺度对胶体粒子在准二维或准一维环境中对、三重体等的扩散运动的影响。该项目的主要目的是了解受限胶体系统的结构和动力学特征，并将这些知识应用于其他系统。这些研究将导致对液体系统性质的更深入的理解，因为它们受限于二维运动，表现出独特的热力学行为。这项工作还将提高对胶体自组织的认识，从而提高对细胞膜性质的认识，并可能最终在纳米技术和微流体装置的控制方面有重要的应用。在这些研究的过程中，本科生和研究生以及博士后研究人员接受了使用最先进的实验和理论技术的培训。

Stuart Rice is supported by a grant from the Experimental Physical Chemistry Program of the Chemistry Division to perform experimental and theoretical studies of the properties of quasi-two-dimensional systems. The systems studied are suspensions of uncharged monodisperse colloid particles in very thin cells. The proposed experimental studies are based on digital video microscopy measurements and image analysis, while the theoretical tools include computer simulations, statistical mechanics, and hydrodynamics. Particular questions to be addressed include 1) the influence of the interplay between the range and strength of the direct (non-hydrodynamic) colloid-colloid interaction and the scale of confinement on the structures of the phases that a dense colloid suspension can support; and 2) the effects of the interplay between the direct colloid-colloid interaction, the hydrodynamic interactions in the suspension, and the scale of confinement on the diffusive motion of pairs, triplets, etc., of colloid particles in a quasi-two-dimensional or quasi-one-dimensional environment.The main thrust of this project is to understand the structural and dynamical features of confined colloid systems and the application of that knowledge to other systems. The studies will lead to a deeper understanding of the properties of liquid systems that, because they are constrained to two-dimensional motion, exhibit unique thermodynamic behavior. This work will also enhance insight about the self-organization of colloids, and hence the nature of cell membranes, and it may ultimately have important applications for nanotechnology and the control of microfluidic devices. In the course of these studies undergraduate and graduate students as well as postdoctoral researchers receive training in the use of state-of-the art experimental and theoretical techniques.