Nanoparticle-Shelled Catalytic Bubble Micromotor

Nanoparticle-shelled bubbles, prepared with glass capillary microfluidics, are functionalized to produce catalytic micromotors that exhibit novel assembly and disassembly behaviors. Stable microbubble rafts are assembled at an air–solvent interface of nonaqueous propylene carbonate (PC) solvent by creating a meniscus using a glass capillary. Upon the addition of hydrogen peroxide fuel, catalytic microbubbles quickly break free from the bubble raft by repelling from each other and self-propelling at the air–fuel interface (a mixture of PC and aqueous hydrogen peroxide). While most of micromotors generate oxygen bubbles on the outer catalytic shell, some micromotors contain cracks and eject bubbles from the hollow shells containing air. Nanoparticle-shelled bubbles with a high buoyancy force are particularly attractive for studying novel propulsion modes and interactions between catalytic bubble micromotors at air–fuel interfaces.