Active Colloidal Molecules in Activity Gradients

Abstract

We consider a rigid assembly of two active Brownian particles, forming an active colloidal dimer, in a gradient of activity. We show analytically that depending on the relative orientation of the two particles the active dimer accumulates in regions of either high or low activity, corresponding to, respectively, chemotaxis and antichemotaxis. Certain active dimers show both chemotactic and antichemotactic behavior, depending on the strength of the activity. Our coarse-grained Fokker-Planck approach yields an effective potential, which we use to construct a nonequilibrium phase diagram that classifies the dimers according to their tactic behavior. Moreover, we show that for certain dimers a higher persistence of the motion is achieved similar to the effect of a steering wheel in macroscopic devices. This work could be useful for designing autonomous active colloidal structures which adjust their motion depending on the local activity gradients.

References in corpus (15)

• Designing phoretic micro- and nano-swimmers
• When are active Brownian particles and run-and-tumble particles equivalent? Consequences for motility-induced phase separation
• Phototaxis of synthetic microswimmers in optical landscapes
• Effective Interactions in Active Brownian Suspensions
• The physics of active polymers and filaments
• Small activity differences drive phase separation in active-passive polymer mixtures
• Odd Diffusivity of Chiral Random Motion
• Pulling and Pushing a Cargo With a Catalytically Active Carrier
• Escape rate of active particles in the effective equilibrium approach
• Chemotaxis of artificial microswimmers in active density waves
• Active Brownian filaments with hydrodynamic interactions: conformations and dynamics
• Self-Polarizing Microswimmers in Active Density Waves
• Dynamics of active particles with space-dependent swim velocity
• Self-assembly of active amphiphilic Janus particles
• Spiral diffusion of rotating self-propellers with stochastic perturbation