3D blocks of graphene mimic elastic structure of cork

The Monash University team, led by Professor Dan Li, has established for the first time an effective way of forming graphene into useful 3D forms by mirroring the structure of cork. First discovered at the University of Manchester in 2010 by Professors Andre Geim and Konstatin Novoselov, graphene is believed to be the thinnest, strongest and most conductive material ever discovered – with potential uses in electronics, flexible touch screens, sensors and composite materials. While previous research has focused mainly on the intrinsic properties and applications of the individual sheets of graphene, Professor Li and his team tackled the challenge of engineering the sheets into macroscopically-useable 3D structures. "When the atomic graphene sheets are assembled together to form 3D structures, they normally end up with porous monoliths that are brittle and perform poorly," he said. "It was generally thought to be highly unlikely that graphene could be engineered into a form that was elastic, which means it recovers well from stress or pressure." The researchers used cork, which is lightweight yet strong, as a model to overcome this challenge. Using a method called freeze casting, they were able to form chemically modified graphene into a 3D structure that mimicked cork. The graphene blocks produced were said to be lighter than air, able to support over 50,000 times their own weight, good conductors of electricity and highly elastic - able to recover from over 80% deformation. "We've been able to effectively preserve the extraordinary qualities of graphene in an elastic 3D form, which paves the way for investigations of new uses of graphene - from aerospace to tissue engineering," Prof Li concluded. "Mimicking the structure of cork has made possible what was thought to be impossible."