Oriented assembly of microparticles by capillarity – Kate Stebe

Date: Thu. February 2nd, 2012, 4:15 pm-5:15 pm
Location: Rockefeller 301

Particles with well defined shapes can be directed to assemble into complex structures by capillarity. Here we explore two themes. First, we explore the assembly of microparticles with well-defined shapes on otherwise planar interfaces to form structures with preferred orientations and with mechanical responses that depend subtly on particle shape. Progress in developing a quantitative understanding of pair interactions and mechanics of assemblies between rod-like particles is described and compared to experiment. Experiments using microparticles with a variety of particle shapes are presented to illustrate a range of possibilities including control over preferred face for assembly and the assembly of particles with complex features in registry. Second, we study particles on curved interfaces. Interface curvature is harnessed as an applied field to drive capillary assembly at well defined locations. On curved interfaces, particle-induced deformations interact with interface curvature field. The resulting capillary energy forces particle migration along curvature gradients and particle alignment along principal axes. Capillary driven migration is explored as a means to direct particles to docking sites, and to mold particle structures.