Floating Soft Robots Could Remove Oil and Contaminants From Water

Engineers at the University of California – Riverside have created a floating, robotic film that could be trained to clean up oil spills at sea or remove contaminants from drinking water. 

The new film, which is powered by light and fueled by water, could be deployed indefinitely to clean remote areas. This is crucial given the fact that many of these areas have nowhere for recharging. 

The research was published in Science Robotics.

Sustainable Soft Robots

Zhiwei Li is a UCR chemist. 

“Our motivation was to make soft robots sustainable and able to adapt on their own to changes in the environment. If sunlight is used for power, this machine is sustainable, and won’t require additional energy sources,” Li said. “The film is also re-usable.”

The film is called Neusbot, named after a category of animals that includes water striders. Insects such as these can move along the surface of lakes and slow-moving streams by using a pulsing motion, which is what the scientists were able to replicate with Neusbot. 

This is not the first film that bends in response to light, but previous versions have been unable to generate the adjustable and mechanical oscillation that Neusbot can. By using this motion, it can funcion on any water surface.

“There aren’t many methods to achieve this controllable movement using light. We solved the problem with a tri-layer film that behaves like a steam engine,” Li said.

Light as the Power Source

The Neusbot uses a similar principle to early trains in order to power it. However, instead of using steam from boiling water to power its motion, it relies on light as the power source. 

The middle layer of the film is porous, and it is able to hold water, as well as iron oxide and copper nanorods. Light energy is converted into heat thanks to the nanorods, which vaporize the water and power the pulsed motion across the water’s surface.

The Neurobot is also immune to an ocean wave overpowering it due to the bottom layer being hydrophobic. This means it will always float back to the surface. The nanomaterials can also withstand high salt concentrations without being damaged. 

“I’m confident about their stability in high salt situations,” Li said. 

Neusobot’s direction is controlled by changing the angle of its light source. With the power of the sun, the robot moves forward, but with an additional light source, the Neurobot can be controlled to swim and clean. 

Its current version has three layers, and the team wants to eventually test a fourth layer that could absorb oil or other chemicals. 

“Normally, people send ships to the scene of an oil spill to clean by hand. Neusbot could do this work like a robot vacuum, but on the water’s surface,” Li said. 

The team also wants to try to control the robot’s oscillation mode more precisely, as well as give it more complex motion.

“We want to demonstrate these robots can do many things that previous versions have not achieved,” Li concluded.