8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P10.28Tue 611:23-14:00Active matter on asymmetric substratesCynthia Reichhardt, 1 Jeffery Drocco, 1 and Charles Reichhardt 11 Los Alamos National Laboratory, P. O. Box 1663, 87545, Los Alamos, New Mexico,USAWe investigate the dynamics of self-driven particles on symmetric and asymmetric substrates. Thissystem could be realized using self-driven colloids on optical traps or swimming microorganismssuch as bacteria in microstructures. In an asymmetric array of funnel-shaped barriers, particles thatundergo only Brownian motion experience no net flow; however, if the particles are undergoingrun and tumble type dynamics we find a net flow of particles or a ratchet effect. We investigatethe effect of different particle dynamics on the ratchet effect. For example, if the particles reorientto follow the barrier walls they encounter, we observe a ratchet effect; however, if the particlesreflect or scatter off the barrier walls, the rectification is reversed or destroyed. We also considerparticle-particle interactions which can either promote or decrease the ratchet effect in accordancewith different rules. In certain swarming models the ratchet effect can even be reduced.28