Mesoscopic simulations of anisotropic chemically-powered nanomotors

TL;DR

This paper presents a mesoscopic simulation model for anisotropic chemically-powered nanomotors, specifically L-shaped colloids, capturing their coupled translational and rotational dynamics and reproducing experimentally observed circling trajectories.

Contribution

The authors develop a parameter-free mesoscopic simulation approach for complex-shaped active colloids, elucidating hydrodynamic effects on their motion.

Findings

Active L-shaped colloids exhibit circling trajectories similar to experiments.

Hydrodynamics significantly influence the coupling between translation and rotation.

The simulation method is useful for preliminary studies before experimental validation.

Abstract

Chemically powered self-propelled colloids generate a motor force by converting locally a source of energy into directed motion, a process that has been explored both in experiments and in computational models. The use of active colloids as building blocks for nanotechnology opens the doors to interesting applications, provided we understand the behaviour of these elementary constituents. We build a consistent mesoscopic simulation model for self-propelled colloids of complex shape with the aim of resolving the coupling between their translational and rotational motion. Considering a passive L-shaped colloidal particle, we study its Brownian dynamics and locate its center of hydrodynamics, the tracking point at which translation and rotation decouple. The active L particle displays the same circling trajectories that have been found experimentally, a result which we compare with the Brownian dynamics model. We put forward the role of hydrodynamics by comparing our results with a fluid model in which the particles' velocities are reset randomly. There, the trajectories only display random orientations. We obtain these original simulation results without any parametrization of the algorithm, which makes it a useful method for the preliminary study of active colloids, prior to experimental work.