Research On Preparation And Motion Mechanism Of GaInSn Liquid Metal Spherical Janus Micromotors

Micro/nano-motors?MNMs?convert light,sound and magnetic energy in their own or the environment into mechanical energy for specific movements.The chemically driven MNMs do not need external energy,and the chemical energy stored in the fuel can be transformed into its own autonomous movement,which has attracted the attention of researchers.At present,chemically driven MNMs are mainly based on the catalytic decomposition of hydrogen peroxide?H₂O₂?.Although some bio-enzymes?such as catalase,glucose oxidase?are involved,it is inevitable that H₂O₂ will participate.There are also other forms of chemical driving that rely mostly on the reaction of active metals with acids,bases or water.However,whether it is toxic H₂O₂ decomposition or the violent reaction of active metals,a large number of bubbles may induce fatal gas embolism in the veins,lungs or brain,thus limiting the application of chemically driven MNMs.Therefore,the exploration of new fuel systems is critical in the direction of chemically driven MNMs.Based on this,a new material with good biocompatibility,Galinstan?GaInSn?liquid metal?LM?,was selected as the preparation material of MNMs.The NaOH was used as fuel to realize the mild self-propulsion motion.In this work,the GaInSn LM spherical Janus micromotors were designed and prepared.The preparation of GaInSn LM microspheres with different particle sizes were achieved by adjusting the ultrasonic time and ultrasonic power.The preparation of GaInSn LM spherical Janus micromotors were completed by deposition techniques such as ion sputtering.The morphology and microstructure were characterized by optical microscopy,scanning electron microscopy and transmission electron microscopy.At the same time,the prepared LM spherical Janus micromotors were placed in the lye and exhibited significant autonomous motion compared to the LM microspheres.The factors influencing the movement speed of GaInSn LM spherical Janus micromotors in lye were observed and analyzed.The relationships between motor velocitys and particle sizes,fuel concentrations,ion concentrations and Janus materials were summarized.The topic studied the motion direction of the motor,and proposed a self-electrophoresis driving mechanism with enhanced galvanic cell reaction by combining the corrosion and the flow of electrons of various parts of the motor in the lye.In addition,the movement of the GaInSn liquid metal Janus micromotor in aqueous ammonia solution was also studied,It was found that the liquid metal micromotors have the same movement trend and motion mechanism in alkaline environment,which only depend on the concentration?or pH?of OH^-in the environment.This project focuses on the research of Ga-based LM in the field of MNMs.We have completed the preparation of GaInSn LM spherical Janus micromotors,realizing self-propulsion in a mild alkaline environment,and proposing the driving principle of the motors in alkaline environment.It has opened up new ideas for the application of Ga-based liquid metal motors in biomedical,micro-welding and environmental testing.