Collective dynamics of chemically active particles trapped at a fluid interface

TL;DR

This paper models the collective behavior of chemically active particles at a fluid interface, revealing how Marangoni flows can counteract clustering caused by capillary attraction, with implications for controlling particle arrangements.

Contribution

It introduces a mean-field model that combines chemical, capillary, and hydrodynamic interactions to predict the dynamics of active particles at fluid interfaces.

Findings

Marangoni flow can prevent clustering instability.

Chemical activity influences particle distribution and stability.

Model parameters are estimated for experimental systems.

Abstract

Chemically active colloids generate changes in the chemical composition of their surrounding solution and thereby induce flows in the ambient fluid which affect their dynamical evolution. Here we study the many-body dynamics of a monolayer of active particles trapped at a fluid-fluid interface. To this end we consider a mean-field model which incorporates the direct pair interaction (including also the capillary interaction which is caused specifically by the interfacial trapping) as well as the effect of hydrodynamic interactions (including the Marangoni flow induced by the response of the interface to the chemical activity). The values of the relevant physical parameters for typical experimental realizations of such systems are estimated and various scenarios, which are predicted by our approach for the dynamics of the monolayer, are discussed. In particular, we show that the chemically-induced Marangoni flow can prevent the clustering instability driven by the capillary attraction.