Phoretic self-propulsion: a mesoscopic description of reaction dynamics that powers motion

TL;DR

This paper develops a mesoscopic model of reaction dynamics to understand how catalytic reactions power the self-propulsion of nano- and microscale particles, with simulations illustrating various propulsion mechanisms.

Contribution

It introduces a mesoscopic framework for reaction dynamics in phoretic self-propulsion, incorporating catalytic reactions at the surface and in the bulk fluid, advancing theoretical understanding.

Findings

Simulations show how different catalytic reactions influence particle motion.

The model captures exothermic and dissociation reactions powering propulsion.

Results highlight the role of mesoscopic reaction dynamics in self-propulsion.

Abstract

The fabrication of synthetic self-propelled particles and the experimental investigations of their dynamics have stimulated interest in self-generated phoretic effects that propel nano- and micron-scale objects. Theoretical modeling of these phenomena is often based on a continuum description of the solvent for different phoretic propulsion mechanisms, including, self-electrophoresis, self-diffusiophoresis and self-thermophoresis. The work in this paper considers various types of catalytic chemical reaction at the motor surface and in the bulk fluid that come into play in mesoscopic descriptions of the dynamics. The formulation is illustrated by developing the mesoscopic reaction dynamics for exothermic and dissociation reactions that are used to power motor motion. The results of simulations of the self-propelled dynamics of composite Janus particles by these mechanisms are presented.