Formation of self-propelling clusters starting from randomly dispersed Brownian particles

TL;DR

This paper demonstrates a chemical method for creating self-propelling clusters from passive colloids and a chemically active colloid, using simulations to show how active motion leads to cluster formation.

Contribution

It introduces a simple chemical strategy and simulation-based analysis for the formation of self-propelling colloidal clusters from passive and active particles.

Findings

Formation of propelling dimers, trimers, tetramers observed

Active colloid induces diffusiophoretic motion in inert colloids

Cluster formation depends on chemical activity and particle size

Abstract

We present a simple chemical strategy for the formation of a self-propelling cluster via the process of capture and assembly of passive colloids on the surface of a chemically active colloid. The two species of colloids that are isotropic and Brownian otherwise interact to form propelling cluster. With the help of coarse-grained numerical simulations, we show that a chemically active colloid can induce diffusiophoretic motility to nearby chemically inert colloids towards itself. This propulsion and then self-assembly can then lead to the formation of active cluster. We observe the formation of propelling dimers, trimers, tetramers, etc. depending on the chemical activity and size of the colloids.