title: Microscopic and continuum descriptions of Janus motor fluid flow fields.
abstract: Active media, whose constituents are able to move autonomously, display novel features that differ from those of equilibrium systems. In addition to naturally occurring active systems such as populations of swimming bacteria, active systems of synthetic self-propelled nanomotors have been developed. These synthetic systems are interesting because of their potential applications in a variety of fields. Janus particles, synthetic motors of spherical geometry with one hemisphere that catalyses the conversion of fuel to product and one non-catalytic hemisphere, can propel themselves in solution by self-diffusiophoresis. In this mechanism, the concentration gradient generated by the asymmetric catalytic activity leads to a force on the motor that induces fluid flows in the surrounding medium. These fluid flows are studied in detail through microscopic simulations of Janus motor motion and continuum theory. It is shown that continuum theory is able to capture many, but not all, features of the dynamics of the Janus motor and the velocity fields of the fluid.This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'.
authors.affiliation: Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK syr20@cam.ac.uk.
authors.forename: Shang Yik
authors.initials: SY
authors.lastname: Reigh
authors.affiliation: Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6 mjhuang@chem.utoronto.ca.
authors.forename: Mu-Jie
authors.identifier: http://orcid.org/0000-0001-7916-9770
authors.initials: MJ
authors.lastname: Huang
authors.affiliation: Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6 jmschofi@chem.utoronto.ca.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Schofield
authors.affiliation: Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6 rkapral@chem.utoronto.ca.
authors.forename: Raymond
authors.initials: R
authors.lastname: Kapral
mesh_terms: D003198:Computer Simulation; D004735:Energy Transfer; D044085:Microfluidics / Q000379:methods*; D008956:Models, Chemical; D009038:Motion; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D013314:Stress, Mechanical
keywords: Janus motors; active matter; diffusiophoresis