Trapping of interacting propelled colloidal particles in inhomogeneous media

TL;DR

This paper introduces a trapping mechanism for propelled colloidal particles using inhomogeneous drive, combining simulations and theoretical analysis to explore particle accumulation, interactions, and clustering for potential applications.

Contribution

It presents a novel trapping method based on inhomogeneous drive, deriving an accumulation parameter, and analyzing the effects of particle interactions and clustering.

Findings

Particles can be trapped using inhomogeneous light-driven mechanisms.

Interaction effects influence the trapping efficiency and cluster formation.

Combined passivity and activity lead to controllable particle clusters.

Abstract

A trapping mechanism for propelled colloidal particles based on an inhomogeneous drive is presented and studied by means of computer simulations. In experiments this method can be realized using photophoretic Janus particles driven by a light source, which shines through a shading mask and leads to an accumulation of the particles in the passive part. An equation for an accumulation parameter is derived using the effective inhomogeneous diffusion constant generated by the inhomogeneous drive. The impact of particle interaction on the trapping mechanism is studied, as well as the interplay between passivity-induced trapping and the emergent self-clustering of systems containing a high density of active particles. The combination of both effects makes the clusters more controllable for applications.