Two-dimensionally controllable untethered swimmer using a T-shaped antenna structure with an electrical discharge in air and water

Abstract Untethered microswimmers that can move freely on the water surface are important for next-generation microfabrication. Here, we propose an untethered swimmer and its navigation method using electrical discharge in air and water. Specifically, we demonstrate that a swimmer with a T-shaped antenna structure can move in the left or right directions according to the high-voltage pulse application between the underwater and aerial electrodes. Furthermore, we demonstrate that a swimmer with a modified T-shaped antenna structure can be controlled on the two-dimensional water surface freely using a four-external aerial electrode system. In addition, by the observation with a high-speed camera (960 fps), we found that the expansion of bubbles generated by the underwater electric discharge near the side antenna terminal of the swimmer propelled the swimmer with the instantaneous maximum initial velocity of ∼300 mm s −1 . Our findings should contribute to the next-generation microfabrication on the water surface.