Self-motile colloidal particles: from directed propulsion to random walk

Phys Rev Lett. 2007 Jul 27;99(4):048102. doi: 10.1103/PhysRevLett.99.048102. Epub 2007 Jul 27.


The motion of an artificial microscale swimmer that uses a chemical reaction catalyzed on its own surface to achieve autonomous propulsion is fully characterized experimentally. It is shown that at short times it has a substantial component of directed motion, with a velocity that depends on the concentration of fuel molecules. At longer times, the motion reverts to a random walk with a substantially enhanced diffusion coefficient. Our results suggest strategies for designing artificial chemotactic systems.