Curvature-driven capillary migration and assembly of rod-like particles.

ABSTRACT: Capillarity can be used to direct anisotropic colloidal particles to precise locations and to orient them by using interface curvature as an applied field. We show this in experiments in which the shape of the interface is molded by pinning to vertical pillars of different cross-sections. These interfaces present well-defined curvature fields that orient and steer particles along complex trajectories. Trajectories and orientations are predicted by a theoretical model in which capillary forces and torques are related to Gaussian curvature gradients and angular deviations from principal directions of curvature. Interface curvature diverges near sharp boundaries, similar to an electric field near a pointed conductor. We exploit this feature to induce migration and assembly at preferred locati

SUBMITTER: Cavallaro M 

PROVIDER: S-EPMC3248516 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature