Dewetting and spreading transitions for active matter on random pinning substrates

Area of Science:

• Physics
• Soft Matter Physics
• Statistical Mechanics

Background:

• Active matter systems, such as self-propelled disks, exhibit complex behaviors influenced by interactions and external environments.
• Understanding phase transitions in active matter is crucial for predicting collective behaviors and designing novel materials.

Purpose of the Study:

• To investigate the phase transitions of sterically interacting self-propelled disks on random pinning substrates.
• To identify and characterize different emergent states, including an active matter wetting transition.

Main Methods:

• Simulations of self-propelled disks with steric interactions on random pinning substrates.
• Analysis of phase separation, cluster formation, and homogeneous wetting.
• Quantification of phase transitions using measures like cluster size and particle coordination.

Main Results:

• Observed transitions from a phase-separated cluster state to a homogeneous wetting state.
• Mapped the wetting transition boundaries concerning activity, disk density, and substrate strength.
• Identified other phases: cluster state, cluster-wetted coexistence, and pinned liquid.

Conclusions:

• Sterically interacting self-propelled disks exhibit rich phase behavior on disordered substrates.
• The study demonstrates an active matter wetting transition, analogous to wetting phenomena in equilibrium systems.
• Cluster size and particle coordination serve as effective indicators for phase identification and transitions.