These Light-powered Soft Robots Could Help Clean the Ocean

IA floating, robotic film recently designed at the University of California-Riverside could offer a solution to oil spill mitigation and removing contaminants from streams, lakes, and drinking water. Described as a collection of soft robots that are powered by light and fueled by water, researchers are calling the film-like mechanism Neusbot, which stems from a category of water-striding insects called neustons that can navigate on the surface of lakes and slow-moving streams using a pulsing motion. While others have been able to create films that change shape in response to light, temperature changes, or electrical stimulus, getting a soft bot to move in a controllable manner has been a challenge. The UC-Riverside team was able to accomplish this via a tri-layer film design that lead researcher Zhiwei Li describes as working like a steam engine. The middle layer of the film contains water as well as iron oxide and copper nanorods. The nanorods convert light energy into heat, “vaporizing the water and powering pulsed motion across the water’s surface.” The bottom layer is hydrophobic, so even if an ocean wave knocks the film around, it floats back to the surface. The nanomaterials are also able to withstand high salt concentrations.