Microswimmers from Scalable Galvanic Displacement

Abstract

Microswimmers are small particles capable of converting available energy sources into propulsion owing to their compositional asymmetry, and are promising for applications ranging from targeted delivery to enhanced mixing at the microscale. However, current fabrication techniques demonstrate limited scalability and/or rely on the excessive use of expensive precursor materials. Here, a scalable Pickering-wax emulsion technique is combined with galvanic electrochemistry, to grow platinum films from copper nanoparticles asymmetrically seeded onto SiO₂ microparticle supports. In this manner, large quantities of Pt-SiO₂ Janus microswimmers are obtained. Utilizing copper as a templating material not only has the potential to reduce synthesis time, material costs, and toxic waste, but also facilitates the further extension of this methodology to a range of functional materials. This electrochemical approach builds upon previous attempts to overcome the current limitations in microswimmer synthesis and offers exciting opportunities for their future development.