Concentration dependent diffusion of self-propelled rods.

摘要: We examine the persistent random motion of self-propelled rods (SPR) as a function area fraction $\ensuremath{\phi}$ and study effect steric interactions on their diffusion properties. SPR length $l$ width $w$ are fabricated with spherocylindrical head attached to beaded chain tail, show directed vibrated substrate. The mean square displacement (MSD) substrate grows linearly time $t$ for $\ensuremath{\phi}lw/l$, before displaying caging is increased, stops well below close packing limit. Direction autocorrelations decay progressively slower $\ensuremath{\phi}$. describe observed decrease propagation speed $c(\ensuremath{\phi})$ tube model. Further, MSD parallel collapse $\ensuremath{\tau}=l/c(\ensuremath{\phi})$ scales $(lt/\ensuremath{\tau}{)}^{2}$, in perpendicular direction than ${l}^{2}t/\ensuremath{\tau}$ $\ensuremath{\phi}$, consistent dynamics inside thinning tube.