Dynamic clustering and chemotactic collapse of self-phoretic active particles

Area of Science:

• Soft matter physics
• Chemical physics
• Theoretical physics

Background:

• Self-phoretic particles exhibit complex behaviors at low concentrations.
• Previous experiments observed pronounced dynamic clustering in these systems.

Purpose of the Study:

• To model and understand the mechanisms behind dynamic clustering in self-phoretic particles.
• To investigate the role of translational and rotational diffusiophoretic motion.

Main Methods:

• Brownian dynamics simulations were employed.
• Langevin dynamics were mapped onto the Keller-Segel model.

Main Results:

• Pronounced dynamic clustering occurs when diffusiophoretic contributions create competing attractive and repulsive interactions.
• Two distinct dynamic clustering states were identified and characterized by power-law-exponential distributions.
• A chemotactic collapse from a gaslike to a collapsed state was observed under mere attraction.

Conclusions:

• The interplay between attractive and repulsive diffusiophoretic forces is crucial for dynamic clustering.
• The identified clustering states and collapse behavior provide insights into active matter self-organization.
• The study establishes a connection between diffusiophoresis and models of bacterial chemotaxis.