Wireless Magnetoelectrochemical Induction of Rotational Motion

Abstract

Electromagnetically induced rotation is a key process of many technological systems that are used in daily life, especially for energy conversion. In this context, the Lorentz force‐induced deviation of charges is a crucial physical phenomenon to generate rotation. Herein, they combine the latter with the concept of bipolar electrochemistry to design a wireless magnetoelectrochemical rotor. Such a device can be considered as a wet analog of a conventional electric motor. The main driving force that propels this actuator is the result of the synergy between the charge‐compensating ion flux along a bipolar electrode and an external magnetic field applied orthogonally to the surface of the object. The trajectory of the wirelessly polarized rotor can be controlled by the orientation of the magnetic field relative to the direction of the global electric field, producing a predictable clockwise or anticlockwise motion. Fine‐tuning of the applied electric field allows for addressing conducting objects having variable characteristic lengths.

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

“…As was shown in Part 1 [1], in the first generation, the micro-MHD vortexes unstably develop with 2D nuclei under a VMHDF. Since the rotation of the VMHDF forms a righthanded system with the external magnetic field, B 0 Ω > 0, as shown in Equation (21a), the VCFs of the micro-MHD vortexes are defined as positive functions, f a j (a a ) > 0 for j = r and f. In the absence of chloride ions, 2D nucleation is unstable in a stationary solution [65], so the main part of the amplitude factor in a stationary solution is positive. BY Equation ( 46), the instability of 2D nucleation under micro-MHD vortexes is therefore defined by the sign of the product of the stationary-solution main part of the VCF, i.e., due to the derived positive values, the micro-MHD vortexes unstably develop together with 2D nuclei.…”

“…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].…”