Rapid swimmer using explosive boiling due to electrical discharge in water

Abstract

A strong micro heat engine that can be used in the untethered state is essential for next-generation microrobotics. Here, we propose a rapid swimmer using explosive boiling due to electrical discharge in water. Specifically, we demonstrate that the water-repellent swimmer that has an aluminum discharge antenna in the rear part can swim with the maximum velocity of ∼14 cm/s on the water surface like a water strider between a pair of parallel electrodes in a shallow water pool by applying direct current high-voltage pulses repeatedly. Moreover, by the video observation with high speed (960 fps), we found that an asymmetrical wave was generated immediately after the discharge, and it propelled the swimmer. Our findings should contribute to next-generation microrobots in the future.