Interaction between catalytic micro motors

Abstract

Starting from a microscopic model for a spherically symmetric active Janus particle, we study the interactions between two such active motors. The ambient fluid mediates a long range hydrodynamic interaction between two motors. This interaction has both direct and indirect hydrodynamic contributions. The direct contribution is due to the propagation of fluid flow that originated from a moving motor and affects the motion of the other motor. The indirect contribution emerges from the re-distribution of the ionic concentrations in the presence of both motors. Electric force exerted on the fluid from this ionic solution enhances the flow pattern and subsequently changes the motion of both motors. By formulating a perturbation method for very far separated motors, we derive analytic results for the transnational and rotational dynamics of the motors. We show that the overall interaction at the leading order, modifies the translational and rotational speeds of motors which scale as $\mathcal{O}\left([1/D{]}^3\right)$ and $\mathcal{O}\left([1/D{]}^4\right)$ with their separation, respectively. Our findings open up the way for studying the collective dynamics of synthetic micro motors.

13 pages, 5 figures

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Cited by in corpus (11)

• Emergent behavior in active colloids
• Which Interactions Dominate in Active Colloids?
• Self-diffusiophoresis induced by fluid interfaces
• Influence of cap weight on the motion of a Janus particle very near a wall
• Electrophoresis of active Janus particles
• Diffusiophoretic propulsion of an isotropic active colloidal particle near a finite-sized disk embedded in a planar fluid-fluid interface
• Orbits, spirals, and trapped states: Dynamics of a phoretic Janus particle in a radial concentration gradient
• Long-wavelength instabilities in a system of interacting active particles
• Diffusiophoresis driven colloidal manipulation and shortcuts to adiabaticity
• A 2-D suspension of active agents: the role of fluid mediated interactions
• Ionic self-phoresis maps onto correlation-induced self-phoresis