Interactions, Dynamics, and Phase Transitions of Colloidal Suspensions

技术摘要：该实验程序通过数字视频显微镜、光学捕获和激光散射的组合来解决胶体悬浮液的物理问题。要研究的系统包括高电荷聚苯乙烯微球和超顺磁铁磁流体乳状液滴。特别感兴趣的领域包括：(1)粒子间势的精确测量；(2)对过冷单分散胶体悬浮液相变的结构和动力学过程进行了分析；(3)以无序固体亚稳性为重点的双分散胶体悬浮液相变分析；(4)光干涉模式对调制基底电位相位行为的影响；(5)有序单层铁磁流体乳剂相变微观动力学。非技术摘要：实验程序在三个层面上检查胶体悬浮液：(1)作为物质的不同状态；(2)作为传统材料的易于研究的类似物；(3)因为它们的自排序特性，在纳米制造、非线性光学和其他先进应用中具有前景。预期的实际效益包括(1)用于确定商业胶体悬浮液中微尺度相互作用的方法；(2)提高了对相变的“原子”尺度过程的理解，特别是在技术上重要的快速凝固情况下；(3)提高了对二元合金体系微观结构、动力学和相变的认识。＊＊＊

9320378 Grier Technical abstract: The experimental program addresses the physics of colloidal suspensions through a combination of digital video microscopy, optical trapping, and laser light scattering. Systems to be investigated include highly charged polystyrene microspheres and superparamagnetic ferrofluid emulsion droplets. Areas of particular interest include: (1) precision measurements of the interparticle potential; (2) analysis of structural and dynamical processes responsible for phase transitions in supercooled monodisperse colloidal suspensions; (3) analysis of phase transitions in bidisperse colloidal suspensions focusing on metastability of disordered solids; (4) effects of phase behavior of modulated substrate potentials simulated by optical interference patterns; (5) microscopic kinetics of phase transitions in quenced single-layer ferrofluid emulsions. Non-technical abstract: The experimental program examines colloidal suspensions on three levels: (1) as distinct states of matter; (2) as easily studied analogs for conventional materials and (3) for their self-ordering properties which hold promise for nanofabrication, nonlinear optics, and other advanced applications. Anticipated practical benefits include (1) a method for determining the microscale interactions in commercial colloidal suspensions; (2) improved understanding of the "atomic"-scale processes responsible for phase transitions, particularly in the technologically important case of rapid solidification; and (3) improved understanding of the microscopic structure, dynamics, and phase transitions of binary alloy systems. ***