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An ancient art just got an extremely modern update. Researchers can now fold origami shapes from graphene, the 1-atom-thick sheets of carbon. The technique could be used to build tiny three-dimensional structures like nano-robots and flexible circuits.

Graphene is a sheet of carbon atoms linked together in one layer and is prized for its variety of 鈥渨onder properties鈥� 鈥� it鈥檚 the strongest material ever studied and is a powerful electrical conductor. Researchers are using origami, the Japanese art of paper-folding, to bend graphene into different shapes. Last year, a team in China built a from multiple layers of graphene oxide sheets, and the bot could walk and turn a corner.

But until now, no one has been able to make an origami crease in just a single sheet, says of Cornell University in Ithaca, New York. 鈥淔olding rules are the same at the macro scale or the micro scale,鈥� he says it鈥檚 just much more difficult to fold a few atoms at a time, because of their size and fragility.

Instant folds

Researchers on Cohen鈥檚 team coated a single layer of graphene with a single layer of silicon dioxide glass, which was half a nanometre thick. The team found that the glass molecules respond differently to the linked carbon atoms when heated, exposed to an electric charge, or soaked in a liquid with a different pH level. These three responses let the team predict how the graphene sheet would expand and contract to produce an instant fold. 鈥淭his really represents the limit,鈥� says Cohen. 鈥淭here鈥檚 not going to be any way to make the sheet any thinner.鈥�

In future, the team hopes that adding other compounds like gold, semiconductors and insulators, will let them create two-dimensional circuits that can be folded into any desirable shape using origami techniques.

鈥淵ou can imagine printing your entire circuit on one of these sheets, then folding it up into a three-dimensional structure that can absorb light, do some kind of calculation, and report back by emitting light at a different frequency,鈥� Cohen says. 鈥淭his work is about being able to build the folding technology, but we鈥檙e starting to work with origami artists to fold cool things.鈥�

The team is at the American Physical Society annual meeting in Baltimore, Maryland.

Image:聽 Itai Cohen Group/Mark Miskin/Cornell University