Interactions, Dynamics, and Phase Transitions of Colloidal Suspensions

9320378格里尔技术摘要：该实验计划通过结合数字视频显微镜、光学捕捉和激光散射来解决胶体悬浮液的物理问题。待研究的体系包括高电荷态聚苯乙烯微球和超顺磁性磁流体乳液滴。特别感兴趣的领域包括：(1)颗粒间势的精确测量；(2)过冷单分散胶体悬浮液相变的结构和动力学过程的分析；(3)双分散胶体悬浮液相变的分析，重点是无序固体的亚稳性；(4)光学干涉图样模拟的调制衬底电位的相行为的影响；(5)有序单层磁流体乳状液相变的微观动力学。非技术摘要：实验计划从三个层面考察胶体悬浮液：(1)作为物质的不同状态；(2)作为传统材料的容易研究的类似物；(3)它们的自序性质，这为纳米制造、非线性光学和其他先进应用提供了希望。预期的实际好处包括：(1)确定商业胶体悬浮液中微尺度相互作用的方法；(2)更好地理解导致相变的“原子”尺度过程，特别是在快速凝固这一具有重要技术意义的情况下；(3)更好地理解二元合金体系的微观结构、动力学和相变。***

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. ***