A spongy, light-as-air material made from crumpled sheets of carbon atoms combines the best properties of rubber and cork as it absorbs and releases liquid. It springs back into shape after being compressed and does not bulge out at the sides when squeezed.
Ray Baughman at the University of Texas at Dallas and Yongsheng Chen at Nankai University in Tianjin, China, and their colleagues assembled thin sheets of graphene oxide at high pressures in alcohol and water, and then freeze dried and heated them to make the aerogel material. They show that their sponge can mop up more than 1,000 times its own weight in engine oil, releasing the oil when squeezed. The material is also more compressible than ordinary rubber at temperatures from −196 °C to 900 °C.
This combination of properties means that the aerogel could be used as an artificial muscle that contracts without getting fatter, the authors say.