Spontaneous membrane formation and self-encapsulation of active rods in an inhomogeneous motility field

Abstract

We study the collective dynamics of self-propelled rods in an inhomogeneous motility field. At the interface between two regions of constant but different motility, a smectic rod layer is spontaneously created through aligning interactions between the active rods, reminiscent of an artificial, semi-permeable membrane. This "active membrane" engulfes rods which are locally trapped in low-motility regions and thereby further enhances the trapping efficiency by self-organization, an effect which we call "self-encapsulation". Our results are gained by computer simulations of self-propelled rod models confined on a two-dimensional planar or spherical surface with a stepwise constant motility field, but the phenomenon should be observable in any geometry with sufficiently large spatial inhomogeneity. We also discuss possibilities to verify our predictions of active-membrane formation in experiments of self-propelled colloidal rods and vibrated granular matter.

References in corpus (25)

• Novel type of phase transition in a system of self-driven particles
• Motility-Induced Phase Separation
• Physics of Microswimmers - Single Particle Motion and Collective Behavior
• Meso-scale turbulence in living fluids
• Topology and Dynamics of Active Nematic Vesicles
• Phototaxis of synthetic microswimmers in optical landscapes
• Chemotaxis and auto-chemotaxis of self-propelling artificial droplet swimmers
• Command of active matter by topological defects and patterns
• Dynamic clustering and chemotactic collapse of self-phoretic active particles
• Transport powered by bacterial turbulence
• Artificial Rheotaxis
• Taming active turbulence with patterned soft interfaces
• Fluid membranes can drive linear aggregation of adsorbed spherical nanoparticles
• Phoretic Interactions Generically Induce Dynamic Clusters and Wave Patterns in Active Colloids
• Topological Sound and Flocking on Curved Surfaces
• Crystallization of self-propelled hard-discs : a new scenario
• Active swarms on a sphere
• Chemotaxis of artificial microswimmers in active density waves
• Aging and rejuvenation of active matter under topological constraints
• Active Brownian particles at interfaces: An effective equilibrium approach
• Osmotaxis in Escherichia coli through changes in motor speed
• Self-Polarizing Microswimmers in Active Density Waves
• Brownian systems with spatially inhomogeneous activity
• Taxis of Artificial Swimmers in a Spatio-Temporally Modulated Activation Medium
• Smectic phases in ionic liquid crystals

Cited by in corpus (8)

• Active glasses
• Hydrodynamics of Active Defects: from order to chaos to defect ordering
• Active crystals on a sphere
• Active Brownian motion with orientation-dependent motility: theory and experiments
• Dynamics of active particles with space-dependent swim velocity
• Colloidal Brazil nut effect in microswimmer mixtures induced by motility contrast
• Effective interactions mediated between two permeable disks in an active fluid
• Active osmotic-like pressure on permeable inclusions