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

TL;DR

This paper experimentally characterizes the motion of self-motile colloidal particles, showing a transition from directed propulsion to enhanced diffusion, and discusses implications for designing chemotactic systems.

Contribution

It provides a detailed experimental analysis of micro-swimmer motion, highlighting the transition from directed to random walk behavior and its dependence on fuel concentration.

Findings

Directed motion at short times depends on fuel concentration.

Long-term motion exhibits enhanced diffusion.

Results inform design strategies for artificial chemotactic systems.

Abstract

The motion of an artificial micro-scale 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.