Graphene Macrostructures Inspired By Cork
Scientists have taken inspiration from one of the oldest natural materials to develop macroscopic structures of graphene.
AsianScientist (Dec. 3, 2012) - Scientists have taken inspiration from one of the oldest natural materials to develop macroscopic structures of graphene.
Published this month in Nature Communications, a Monash University study has established an effective way of forming graphene, which normally exists in very thin layers, into useful three-dimensional (3D) forms by mirroring the structure of cork.
Graphene is formed when graphite is broken down into layers one atom thick. In this form, it is very strong, chemically stable, and an excellent conductor of electricity with many applications.
But while previous research had focused mainly on the intrinsic properties and applications of the individual sheets, here the team tackled the challenge of engineering the sheets into macroscopically-usable 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," said Professor Dan Li who led the study. "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, the researchers were able to form chemically modified graphene into a 3D structure that mimicked cork.
Because of its unique biomimetic hierarchical structure, the graphene blocks produced were 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 percent 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," Li said.
The article can be found at: Qiu L et al. (2012) Biomimetic superelastic graphene-based cellular monoliths.
Source: Monash University; Photo:hey mr glen/Flickr/CC.
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