title: Size dependence of the propulsion velocity for catalytic Janus-sphere swimmers.
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.
authors.affiliation: Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom. s.ebbens@sheffield.ac.uk
authors.forename: Stephen
authors.initials: S
authors.lastname: Ebbens
authors.forename: Mei-Hsien
authors.initials: MH
authors.lastname: Tu
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Howse
authors.forename: Ramin
authors.initials: R
authors.lastname: Golestanian
mesh_terms: D002384:Catalysis; D003102:Colloids / Q000737:chemistry*; D003198:Computer Simulation; D004058:Diffusion; D008956:Models, Chemical; D009038:Motion
chemical_list: D003102:Colloids