Soft Gel Responds to Light/Absorbs Water CHemical Reaction
May, 2013 Gel Material UC Berkeley California, US
A new material controlled by light may help scientists build better soft-bodied robots. The developers of the gel say they were inspired by the way a plant grows to face the sunlight. Unlike plants, though, the gel can be made to flex and move almost instantaneously. The UC Berkeley scientists created the gel using graphene and a synthetic protein similar to elastin, which is found in humans‘ blood vessels, skin and more. The synthetic elastin, created from genetically engineered bacteria, absorbs water at room temperature, but at higher temperatures it expels the water and shrinks. [Read also: „ Soft Robots Make World Safer for Humans“]
Graphene produces heat when exposed to near-infrared light. Together, the two materials make a light-con- trolled gel, said professor Seung-Wuk Lee of UC Berkeley‘s department of bioengineering. „The graphene is heated by the light, and then the elastin is responding to the heat induced by the light.“
By making parts of the new gel less porous, the team could control how the material bends. The more porous side absorbed and expelled water faster, making the material shrink unevenly, which resulted in a gel that could bend in a predictable, repeatable way.