Microscopic and continuum descriptions of Janus motor fluid flow fields

TL;DR

This paper compares microscopic simulations and continuum theory to analyze fluid flow fields generated by Janus self-propelled nanomotors, highlighting the strengths and limitations of continuum models in capturing their dynamics.

Contribution

It provides a detailed comparison between microscopic and continuum descriptions of Janus motor fluid flows, revealing where continuum theory succeeds and where it falls short.

Findings

Continuum theory captures many features of Janus motor fluid flows.

Microscopic simulations reveal complex flow details not fully described by continuum models.

The study advances understanding of active matter fluid dynamics.

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 catalyzes the conversion of fuel to product and one noncatalytic 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.