Abstract
We examine the persistent random motion of self-propelled rods (SPR) as a function of the area fraction and study the effect of steric interactions on their diffusion properties. SPR of length and width are fabricated with a spherocylindrical head attached to a beaded chain tail, and show directed motion on a vibrated substrate. The mean square displacement (MSD) on the substrate grows linearly with time for , before displaying caging as is increased, and stops well below the close packing limit. Direction autocorrelations decay progressively slower with . We describe the observed decrease of SPR propagation speed with a tube model. Further, MSD parallel to the SPR collapse with and scales as , and MSD in the perpendicular direction grows progressively slower than with , consistent with dynamics inside a thinning tube.
- Received 28 August 2009
DOI:https://doi.org/10.1103/PhysRevLett.104.088001
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