Brownian Dynamics Simulations of the Short and Long-Time Behavior of Osmotic Motors Subject to a Magnetic Field

Reaction-driven propulsion of colloidal particles, such as osmotic motors, consists of the localized generation of a concentration gradient by an on-board surface chemical reaction. As shown in recent experiments, the directed motion of these particles is hindered by their rotary Brownian motion and thus preventing its potential to be completely realized. However, if the self-propelled particle is magnetized (or contains a magnetic dipole), its directionality can be controlled externally by a magnetic field and the conversion from chemical energy into motion becomes more effective. In this work, we investigate the short and long-time behavior of osmotic motors immersed in a dispersion of reactant particles subject to a magnetic field using Brownian dynamics simulations. The strength of the magnetic field is controlled by the Langevin parameter α, which ultimately dictates the long-time behavior of the osmotic motor.  The rotational and translational velocity of the osmotic motor for different surface reaction speeds, reactant particle concentrations, and Langevin parameters are investigated.