# Active Brownian particles at interfaces: An effective equilibrium approach

## TL;DR

This paper develops a theoretical framework using dynamical density functional theory to analyze active colloids at interfaces, revealing new phenomena like wetting, drying, and capillary phase transitions related to motility-induced phase separation.

## Contribution

It introduces an effective equilibrium approach to predict interface phenomena of active particles, including wetting, drying, and capillary effects, extending understanding of active matter behavior.

## Key findings

- Prediction of wetting and drying transitions at repulsive walls
- Identification of capillary condensation and evaporation in slit pores
- Connection of interface phenomena to motility-induced phase separation

## Abstract

A simple theoretical approach is used to investigate active colloids at the free interface and near repulsive substrates. We employ dynamical density functional theory to determine the steady-state density profiles in an effective equilibrium system [Farage et al., Phys. Rev. E, 91 (2015) 042310]. In addition to the known accumulation at surfaces, we predict wetting and drying transitions at a flat repulsive wall and capillary condensation and evaporation in a slit pore. These new phenomena are closely related to the motility-induced phase separation (MIPS) in the bulk.