Tracking the Kinetics of Colloidomer Sedimentation with Holographic Video Microscopy

Colloidomers consist of micrometer-scale emulsion droplets bound by programmed surface interactions into flexible chains. The fluid-fluid boundary condition at a colloidomer's surface differs from the non-slip boundary conditions presented by solid colloidal spheres, and influences how a colloidomer sediments through viscous fluids. We use holographic video microscopy to track the three-dimensional motions of colloidomers as they relax from initial extended configurations created through holographic optical trapping. These measurements reveal the role of hydrodynamic coupling in the kinetics of colloidomer settling under non-equilibrium conditions.