(722h) Shape-Directed Dynamics of Active Colloids Powered By Contact Charge Electrophoresis

Active colloids harness energy from their environment to power directed motions relative to their fluid surroundings. Previously, we showed how contact charge electrophoresis (CCEP) can be used to power motions of metallodielectric Janus spheres through a dielectric fluid separating two biased electrodes. This talk will move beyond Janus spheres to describe how the shape and symmetry of a colloidal particle can be used to direct additional motions and functions powered by CCEP. Particles of different shapes and symmetries are prepared by photolithography and metal evaporation. The shape of the conductive patches on the particle surface determines the amount of charge acquired on contact with the electrodes as well as the electric forces and torques driving particle motions. The overall shape of the particle determines its linear and rotational motions through viscous surroundings. In addition to new types of particle motion, we show how asymmetric colloids powered by CCEP can be used to pick-up, transport, and deliver droplets and bubbles. Our results demonstrate how particle asymmetries can be used to encode different dynamics and functions in active colloids powered by simple energy inputs.