470515 Curvature Capillary Repulsion

Wednesday, November 16, 2016: 1:45 PM
Union Square 23 & 24 (Hilton San Francisco Union Square)
Iris B. Liu, Lu Yao, Nima Sharifi-Mood and Kathleen J. Stebe, Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA

On a curved fluid interface, microparticles interact with the curvature field in a manner akin to a charged multipole in an applied external electrostatic field. The interaction is driven by capillarity where particles move to minimize the excess area associated with the distortions that they make in the interface. Here, we present capillary curvature repulsion. We study microparticles migration on a curved host interface with zero mean curvature, which is created by pinning an oil-water interface around a micropost. We identify curvature fields in which microparticles migrate away from high curvature sites. By a combination of theory and experiment, we show how these interactions occur and their relationship to particle and post geometry. By tuning repulsion and attraction, we define sites far from bounding surfaces for particle assembly at equilibrium on interfaces, and explore collective behaviors of particles near these sites. Understanding of effects of curvature on the behavior of microparticles at the interfaces provides implications to create reconfigurable hierarchical structures.

Extended Abstract: File Not Uploaded
See more of this Session: Dynamic Processes at Interfaces
See more of this Group/Topical: Engineering Sciences and Fundamentals