Minimal numerical ingredients describe chemical microswimmers's 3D motion

TL;DR

This paper introduces a minimal dissipative particle-hydrodynamics model that captures the complex 3D motion of chemical microswimmers by balancing hydrodynamic interactions, shape, and mass asymmetries, aiding future synthetic design.

Contribution

A coarse-grained model that simplifies the physics of microswimmers while accurately reproducing diverse experimental behaviors and enabling design of complex 3D microswimmer motion.

Findings

Model reproduces various experimental microswimmer dynamics.

Hydrodynamic interactions, shape, and mass asymmetries are key to motion.

Potential to guide synthetic fabrication of complex microswimmers.

Abstract

The underlying mechanisms and physics of catalytic Janus microswimmers is highly complex, requiring details of the associated phoretic fields and the physiochemical properties of catalyst, particle, boundaries, and the fuel used. Therefore, developing a minimal (and more general) model capable of capturing the overall dynamics of these autonomous particles is highly desirable. In the presented work, we demonstrate that a coarse-grained dissipative particle-hydrodynamics model is capable of describing the behaviour of various chemical microswimmer systems. Specifically, we show how a competing balance between hydrodynamic interactions experienced by a squirmer in the presence of a substrate, gravity, and mass and shape asymmetries can reproduce a range of dynamics seen in different experimental systems. We hope that our general model will inspire further synthetic work where various modes of swimmer motion can be encoded via shape and mass during fabrication, helping to realise the still outstanding goal of microswimmers capable of complex 3-D behaviour