Self-Sustained Rotation of Lorentz Force-Driven Janus Systems

Abstract

Rotation is an interesting type of motion that is currently involved in many technological applications. In this frame, different and sophisticated external stimuli to induce rotation have been developed. In this work, we have designed a simple and original self-propelled bimetallic Janus rotor powered by the synergy between a spontaneous electric and ionic current, produced by two coupled redox reactions, and a magnetic field, placed orthogonal to the surface of the device. Such a combination induces a magnetohydrodynamic vortex at each extremity of the rotor arm, which generates an overall driving force able to propel the rotor. Furthermore, the motion of the self-polarized object can be controlled by the direction of the spontaneous electric current or the orientation of the external magnetic field, resulting in a predictable clockwise or anticlockwise motion. In addition, these devices exhibit directional corkscrew-type displacement, when representing their displacement as a function of time, producing time−space specular behavior. The concept can be used to design alternative self-mixing systems for a variety of (micro)fluidic equipment.

Theory of Chiral Electrodeposition by Micro-Nano-Vortexes under a Vertical Magnetic Field-2: Chiral Three-Dimensional (3D) Nucleation by Nano-Vortexes

“…In recent days, various studies on the transport of microscopic materials in solutions by using MHD forces have been reported. Kuhn et al proposed an efficient alternative mechanism with which to power self-electrophoretic Mg/Pt Janus swimmers based on the Lorentz force and designed a self-propelled bimetallic Janus rotor and a wireless magnetoelectrochemical rotor [63][64][65]. Celzard et al proposed self-propelled particles based on the MHD acceleration of the surrounding fluid [66].…”

Wireless Magnetoelectrochemical Induction of Rotational Motion

“…[ 21 , 22 , 23 , 24 , 25 , 26 ] Recently the concept has also been successfully exploited to boost the kinetics of self‐electrophoretic devices. [ 27 , 28 , 29 ] In this case, a potential difference ( ΔV ) is induced between the two extremities of a conducting object by coupling thermodynamically spontaneous redox reactions occurring at each end of the device. Such self‐polarized objects exhibit predictable clockwise or anticlockwise motion as a function of the orientation of the magnetic field.…”