Droplet microfluidic synthesis of shape-tunable self-propelled catalytic micromotors and their application to water treatment

Self-propelled catalytic micromotors have shown significant potential in the fields from biomedicine to environmental remediation. Here, we developed a microfiber-confined microfluidic approach to controllably fabricate droplet-templated micromotors for water treatment. Utilizing transformable droplets embedded in microfibers as the template, the morphology of microparticles can be controlled from sphere, spindle to drum shape. Moreover, by simply adjusting the flow rates, precise control over the shape and size of resulting microparticles can be achieved. By coating MnO2 and Fe3O4 nanoparticles on the surface, micromotors propelled by a catalytic reaction were functionalized which can fulfill specific tasks. The incorporation of Fe3O4 nanoparticles endows micromotors with magnetic functionality, which also can serve as an effective Fenton-like catalyst for organic pollutants degradation. Benefiting from the MnO2 nanoparticles for catalytic decomposition of H2O2 to generate gas bubbles, the micromotors are capable of moving autonomously, which further enhances the mass transfer in solution. Consequently, the obtained micromotors exhibited good bubble-propelled motion, effective pollutant degradation capacity, as well as easy recovery by magnetic attraction. The flexible strategy allows for the generation of advanced microparticles with well-controlled structures, thus showing highly promising potential for various engineering applications. [GRAPHICS] .

Automated summary

A novel microfluidic approach using microfiber confinement was developed to fabricate droplet-templated micromotors for water treatment. By adjusting flow rates and coating nanoparticles on the surface, precise control over the shape and size of resulting micromotors can be achieved, showing good bubble-propelled motion and effective pollutant degradation capacity.