Distinct dynamics of self-propelled bowl-shaped micromotors caused by shape effect: Concave vs convex

Although artificial micromotors with unconventional shapes are emerging as a powerful tool in various applications, little research has been undertaken to clarify their propulsion mechanism, especially how the shape effect alters bubble dynamics and hydrodynamic flows. In this study, we fabricated two types of bowl-shaped investigate distinct due concave convex surfaces, by coating platinum (Pt) layer on either surface or micromotor. single-bubble mode at low fuel concentration, concave-surface-Pt-coated micromotor moved unexpectedly slower than convex-surface-Pt-coated micromotor, growth was also much that surface. It elucidated confinement hindered replenishment thus catalytic reaction. We further introduced Kelvin impulse explain why eventually weakened from jet flows caused collapse. multi-bubble high interaction among bubbles rendered “more is less” phenomenon—increase concentration did not enhance maximum instantaneous speed. These findings inspire development new manipulation strategies utilizing micromotors.