Wetting transition of active Brownian particles on a thin membrane

TL;DR

This paper investigates a non-equilibrium wetting transition of active Brownian particles at a membrane, revealing dimensionality-dependent transition types and signatures of phase change.

Contribution

It introduces a minimal model for active particles interacting with a porous membrane, demonstrating a non-equilibrium wetting transition influenced by system dimensionality.

Findings

Wetting transition signatures depend on membrane interaction strength.

2D systems show continuous transition with large fluctuations.

3D systems exhibit a sharp, fluctuation-free transition.

Abstract

We study non-equilibrium analogues of surface phase transitions in a minimal model of active particles in contact with a purely repulsive potential barrier that mimics a thin porous membrane. Under conditions of bulk motility-induced phase separation, the interaction strength $\varepsilon_w$ of the barrier controls the affinity of the dense phase for the barrier region. We uncover clear signatures of a wetting phase transition as $\varepsilon_w$ is varied. In common with its equilibrium counterpart, the character of this transition depends on the system dimensionality: a continuous transition with large density fluctuations and gas bubbles is uncovered in 2d while 3d systems exhibit a sharp transition absent of large correlations.