How to Make Graphene Paper

Carbon fibres were developed in the 1950s and have since helped to revolutionise the design, manufacture and performance of everything from yachts and planes to cars and bicycles.

Now, 60 years later, a new material looks set to have a similar impact: graphene paper.

For the moment, it’s only possible to make graphene in tiny scraps. So the trick in scaling it up is to find ways to stack these sheets and bond them together to make something larger. Trouble is nobody has yet managed this feat.

Today, Yilun Liu and pals at Tsinghua University in Beijing, calculate from first principles what such a material might be like.

The trick in making graphene paper strong is to find ways to bind small sheets of graphene together end-to-end to make a larger sheet but also to bind layers together using bonds between them. Many biological materials use the same trick to increase their strength, materials such as bone, teeth and nacre.

Of course, these materials are only as strong as their weakest link. So Yilun and co have calculated what sort of strength we can expect from graphene paper.

Their answer is that it depends on the types of cross-links, their strength, number and whether they reform quickly after they are broken as epoxy and hydroxyl groups do.

This approach allows engineers to design the material accordingly. In fact, the new model can be used to design other papers too so it may be possible to improve the properties of all kinds of thin, layered sheets.

Yilun and co’s model makes a number of interesting predictions. For example, it says the links between graphene layers will increase the distance between them, thereby reducing the density to about half that of graphite. So graphene paper is not only going to be strong but also very light.

All it needs now is somebody to go ahead and create a sheet of this stuff. And if it can one day be made cheaply and easily enough we’ll see it everywhere–both inside and outside our bodies.

Ref: arxiv.org/abs/1105.0138: Mechanical Properties of Graphene Papers

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