Tunable long range forces mediated by self-propelled colloidal hard spheres

Abstract

Using Brownian dynamics simulations, we systematically study the effective interaction between two parallel hard walls in a 2D suspension of self-propelled (active) colloidal hard spheres, and we find that the effective force between two hard walls can be tuned from a long range repulsion into a long range attraction by changing the density of active particles. At relatively high densities, the active hard spheres can form a dynamic crystalline bridge, which induces a strong oscillating long range dynamic wetting repulsion between the walls. With decreasing density, the dynamic bridge gradually breaks, and an intriguing long range dynamic depletion attraction arises. A similar effect occurs in a quasi-2D suspension of self-propelled colloidal hard spheres by changing the height of the confinement. Our results open up new possibilities to manipulate the motion and assembly of microscopic objects by using active matter.

Accepted in Physical Review Letters

References in corpus (6)

• Self-motile colloidal particles: from directed propulsion to random walk
• Meso-scale turbulence in living fluids
• Statistical Mechanics of Interacting Run-and-Tumble Bacteria
• When are active Brownian particles and run-and-tumble particles equivalent? Consequences for motility-induced phase separation
• Motility-sorting of self-propelled particles in micro-channels
• Tuning effective interactions close to the critical point in colloidal suspensions

Cited by in corpus (8)

• Pressure and Phase Equilibria in Interacting Active Brownian Spheres
• Multidimensional Stationary Probability Distribution for Interacting Active Particles
• How does a flexible chain of active particles swell?
• Active Brownian particles at interfaces: An effective equilibrium approach
• Effective equilibrium states in mixtures of active particles driven by colored noise
• Emergence of collective dynamical chirality for achiral active particles
• Three-body correlations and conditional forces in suspensions of active hard disks
• Recovery of mechanical pressure in a gas of underdamped active dumbbells with Brownian noise