Types Of Micromotors Research Articles

Superfast Active Droplets as Micromotors for Locomotion of Passive Droplets and Intensification of Mixing.

Micromotors are fascinating objects that are able to move autonomously and perform various complex tasks related to drug delivery, chemical processes, and environmental remediation. Among the types of micromotors, droplet-based micromotors are characterized by a wide range of functional properties related to the capability of encapsulation and deformation and the possibility of using them as microreactors. Relevant problems of micromotor utilization in the chemical processes include intensification of mixing and locomotion of passive objects. In this paper, the technique for preparation of superfast active droplets, which can be used as micromotors for effective locomotion of passive droplets in the oil-in-water emulsion, is demonstrated. The possibility of passive droplet locomotion in the emulsion is determined by a relation between the diameters of active and passive droplets. If the diameter of active droplets is larger than the diameter of passive droplets, the agglomerates form spontaneously in the emulsion and move in a straight line. In the case of the opposite relation between diameters, the agglomerates consisting of active and passive droplets rotate intensively. This makes it impossible to move the passive droplets to a given distance. Such micromotors can achieve unprecedentedly high velocities of motion and can be used to intensify mixing on the microscales.

Laser-Ignited Micromotor Using Multiple Stacked Solid Propellant Pellets

This study proposes the laser-ignited micromotor (LIMO), which is a new propulsion system for CubeSats to overcome the problems associated with conventional chemical propellants. The solid propellant pellets are stacked and stored in the micromotor. This concept makes it possible to design the total impulse of the micromotor in a flexible manner at a low cost and in a short time, depending on microsatellite missions. In addition, a laser-ignition system is integrated with the micromotor to address the problems of ignition delay and the difficulty in cutting the high-current feed lines of the ignition system. Firing tests are conducted in a vacuum chamber using four types of micromotors with different characteristics; that is, each type has a different number of solid propellant pellets and a different ignition system. Total impulses of 184 and are achieved by the two types of LIMOs with 98 and 140 stored pellets, respectively, with a burning rate of . Ignition delay is improved from 0.37 to 0.04 s by using the laser-ignition system. In addition, an engineering model of the LIMO is designed.

Organic dye removal by MnO2 and Ag micromotors under various ambient conditions: The comparison between two abatement mechanisms

MnO2- and Ag- based micromotors were developed recently as new types of micromotors with the advantage of low costs and have been utilized to treat environmental pollutants. However, knowledge about the effects of ambient conditions on the performance of them is still lacking. In this article, the influences of pH, electrolytes and surfactant on the treatment of organic dye (with methylene blue as the representative) by the commercial MnO2 and Ag micromotors with H2O2 as the fuel were studied. In the motion visualization experiments, besides the routine types of trajectories, the circular motion of micromotors around the already formed bubbles was observed for the first time. In the pollutant removal experiments, two abatement mechanisms (catalytic degradation and adsorptive bubble separation) were studied. The decolorization efficiency for MnO2 due to catalytic degradation increased with the increasing pH, which disagreed with previous studies in which no H2O2 was added. The inhibitory effects of the tested electrolytes were in the order: CaCl2>NaNO3>NaCl. Surfactant can increase the decolorization efficiency only under highly alkaline conditions. For Ag, decolorization only occurs with the existence of surfactant at high pH values (pH = 11.4) indicating that the dominant mechanism is adsorptive bubble separation.

Catheter-Based Microrotary Motor Enabled by Ferrofluid for Microendoscope Applications

This paper reports the first microrotary motor enabled with a novel ferrofluid-based levitation mechanism used as an extremely simple miniaturized bearing material for microendoscopy applications. The ferrofluid bearing is magnetically sustained on the permanent magnet rotor that is levitated by the bearing layer inside a tubular substrate, an endoscope catheter. The levitated rotor is electromagnetically driven by two photo-defined meander-type coils formed around the outer walls of the catheter that enables 90°-step angular actuation of the rotor. Two types of micromotors with 1.6-mm- and 500- $\mu \text{m}$ -sized rotors are designed, fabricated, and tested. The fabricated prototypes of the motors are successfully operated to rotate the prism mirrors integrated with the motors, with revolution rates as high as 1875 and 1500 r/min for the 1.6-mm and 500- $\mu \text{m}$ rotor types, respectively. Thermal behaviors of the devices are also characterized and reported. The experimental results demonstrate the effectiveness of the motor design and indicate high potential for side-viewing microendoscopic applications. [2015-0232]

New Construction of an Electro-Conjugate Fluid-Jet-Driven Micromotor with an Inner Diameter of 2 mm

Electro-conjugate fluid (hereafter abbreviated as ECF) is a kind of dielectric fluid that produces a powerful jet flow (ECF jet) between rod-type electrodes in an applied non-uniform static electric field. By using the ECF jet, a new type of micromotor with a simple structure and light weight can be realized. Until now, some types of ECF micromotors have been developed with a 3 mm inner diameter. In this study, a micromotor is fabricated with a 2 mm inner diameter in order to improve the output power density, using the ECF jet. The micromotor was first designed and fabricated; then, the performance of the motor was measured. The experimental results confirm that the micromotor developed here has a higher power density than the micromotors previously developed with 3 mm inner diameter.