One Step Fabrication Of Multifunctional Micromotors

Although micromotor/artificial motor has experienced tremendous progresses in recent years, their fabrication normally involves complex steps or expensive equipment, which remains a hindrance for its further application. In this paper, we report a one-step method to fabricate the Janus micromotors based on single oil-in-water emulsion solvent evaporation technique. Not only this method is simple, low cost and highly reproducible, but a variety of functional materials can also be introduced during emulsification process to realize controlled movement, drug encapsulation, cargo transportation and environment remediation. Therefore, such a simple one-step and scalable fabrication of micromotor may have great potential in a wide range of practical applications.In the first part, we report a one-step fabrication method to obtain multifunctional micromotors. This method is based on an emulsion solvent evaporation technique. Unlike the previously developed methods to construct a micromotor in a stepwise fashion, all components of the current micromotor, such as biodegradable polycaprolactone(PCL), catalytically active platinum nanoparticles(PtNPs) and other functional materials including magnetic iron oxide nanoparticles(Fe3O4NPs) and fluorescent coumarin molecules are introduced simultaneously within a single step. The resulting micromotor possesses an asymmetric structure. Not only can this micromotor move autonomously in salt solution upon the addition of a fuel, it also exhibits multiple functions, such as magnetic control, enzymatic disassembly and sustained release. The simple, scalable fabrication process and the multiple functionalities of the resultant micromotor make our approach an attractive candidate to produce micromotors for practical applications.In the following section, on the basis of the first work, we adopted the approach of oil-in-water emulsion method to fabricate the PCL-Mg Janus micromotor in just one step, the motor relies on the reaction between water and magnesium. It’s worth noting that the motor can not only move automatically in NaCl aqueous solution, but also can react with the H2O2 without the participation of Pt catalyst. The generated H2 or O2 bubbles drive the micromotor moving forward. We use the PCL-Mg Janus micromotors to detect the silver ions. At the last part, the PCL-Mg Janus micromotors was used to remove the heavy metals in waste water. We find that the moving micromotors show higher efficiency in removing the heavy metals as compared to the static counterpart.