Magnetic Transport of Ferrofluidic Bubble Micromotors

Previous research has established the ability for gas-cored, buoyant nanoparticle-shelled bubbles to self-propel with the use of a catalytic coating and hydrogen peroxide (Adams et al., Adv. Mater. Interfaces 7, 1901583 (2020)) These bubbles are coated with a thin film of titanium and platinum to act as the catalyst, float on a surface of propylene carbonate solvent, and move using hydrogen peroxide as a fuel. However, this motor action repels the bubbles away from each other and does not allow for controlled locomotion. In this study, we are infusing the nanoparticle shells with an oil-based ferrofluid, building off methods for creating air/oil/water compound bubbles with glass capillary microfluidics (Lee et al., Langmuir 26, 2227 (2010)). By placing these now magnetized bubbles in the presence of a magnetic field, we can now control the direction of motion for catalytic bubble micromotors.