Active rotational dynamics of a self-diffusiophoretic colloidal motor

TL;DR

This paper investigates the active rotational behavior of a chemically-powered colloidal motor driven by self-diffusiophoresis, using continuum theory and simulations to understand how shape and surface reactions induce rotation.

Contribution

It provides a combined theoretical and simulation framework to analyze how surface heterogeneity and shape influence active rotational motion in synthetic colloidal motors.

Findings

Active rotation arises from broken spherical symmetry due to concentration gradients.

Surface shape and catalytic activity variations significantly affect rotational dynamics.

The study offers insights applicable to controlling motor motion in collective systems.

Abstract

The dynamics of a spherical chemically-powered synthetic colloidal motor that operates by a self-diffusiophoretic mechanism and has a catalytic domain of arbitrary shape is studied using both continuum theory and particle-based simulations. The motor executes active rotational motion when self-generated concentration gradients and interactions between the chemical species and colloidal motor surface break spherical symmetry. Local variations of chemical reaction rates on the motor catalytic surface with catalytic domain sizes and shapes provide such broken symmetry conditions. A continuum theoretical description of the active rotational motion is given, along with the results of particle-based simulations of the active dynamics. From these results a detailed description of the factors responsible for the active rotational dynamics can be given. Since active rotational motion often plays a significant part in the nature of the collective dynamics of many-motor systems and can be used to control motor motion in targeted cargo transport, our results should find applications beyond those considered here.