The collision phenomena of Janus polymer micro-plate motors propelled by oscillating micro-bubbles

The collision phenomena of self-propelled micro-plate motors are significantly different from classical life-less particles. The Janus micro-plate motors used in this study are 5 and 10 μm in diameter and driven by catalytic decomposition of hydrogen peroxide. Periodically oscillating oxygen bubbles drive the motor in rugged straight or spiral motion. Since the inertia effect of mass is no longer important for slow motion in low Reynold number liquid, the momentum law of collision shows some new characteristics due to the constant self-propelling force. We found a bounce back collision and a linear collision between the bubbles of one motor and the micromotor plates as well as between 2 microplates and present a basic theoretical concept. In addition we show experimentally that these 2D particles are able to destroy emerging gas bubbles. More complex collision dynamics may exist for a higher concentration of self-propelled motors.