Abstract

This talk describes recent simulation studies of a wetting transition in a minimal model of active matter. To set the scene and establish terminology, we begin by reviewing how surface phase transitions manifest in assembles of passive (ie equilibrium) particles at an attractive impenetrable substrate. We then address the case of a system of active Brownian particles in contact with a purely repulsive potential barrier that mimics a thin permeable membrane. Under conditions of bulk motility-induced phase separation, the interaction strength ε of the barrier controls the affinity of the dense phase for the barrier region. We uncover clear signatures of a wetting phase transition as ε is varied. In common with its equilibrium counterpart, the character of this transition depends on the system dimensionality: a continuous transition with enhanced density fluctuations and gas bubbles is uncovered in 2d while 3d systems exhibit a sharp transition absent of large correlations.