Small robot swimmers that heal themselves from damage

Science Daily  March 24, 2021
Swimming robots that can “swim” through fluids and carry out useful functions, such as cleaning up the environment, delivering drugs, are often made of brittle polymers or soft hydrogels, which can easily crack or tear. Researchers at UC San Diego made swimmers that were 2 cm long in the shape of a fish that contained a conductive bottom layer; a rigid, hydrophobic middle layer; and an upper strip of aligned, strongly magnetic microparticles. Platinum in the tail, which reacted with hydrogen peroxide fuel to form oxygen bubbles propelled the robot. In a petri dish filled with a weak hydrogen peroxide solution, it moved around the edge of the dish. When the swimmer was cut with a blade, the tail kept traveling around until it approached the rest of the body, reforming the fish shape through a strong magnetic interaction. The robots could also heal themselves when cut into three pieces, or when the magnetic strip was placed in different configurations. The versatile, fast, and simple self-healing strategy could be an important step toward on-the-fly repair for small-scale swimmers and robots, the researchers say. VIDEO …read more. TECHNICAL ARTICLE 

Credit: Nano Lett. 2021, 21, 5, 2240–2247, February 22, 2021