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Updated: May 23, 2026

Preparation and 3D Tracking of Catalytic Swimming Devices
Published on: July 1, 2016
Size dependence of the propulsion velocity for catalytic Janus-sphere swimmers
Stephen Ebbens1, Mei-Hsien Tu, Jonathan R Howse
1Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom. s.ebbens@sheffield.ac.uk
Abstract:
The propulsion velocity of active colloids that asymmetrically catalyze a chemical reaction is probed experimentally as a function of their sizes. It is found that over the experimentally accessible range, the velocity decays as a function of size, with a rate that is compatible with an inverse size dependence. A diffusion-reaction model for the concentrations of the fuel and waste molecules that takes into account a two-step process for the asymmetric catalytic activity on the surface of the colloid is shown to predict a similar behavior for colloids at the large size limit, with a saturation for smaller sizes.
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