Graphene "kirigami" could lead to the development of some of the smallest machines known to science.
In kirigami, artists cut paper into intricate designs, such as snowflakes. This new study reveals ultra-thin graphene can be cut in a similar way, with promising results, Cornell University reported.
A team of researchers demonstrated when kirigami was used on 10-micron sheets of graphene, it could bend just like paper. The material is extremely sticky at this scale, so the scientists suspended it in water and added surfactants to make it slippery and easier to manipulate. They also added gold tab "handles" so that the shapes could be grabbed. To achieve this feat, the researchers used a laser to cut up paper models of the designs before creating them with graphene.
"It was really true exploration, cutting things out of paper and playing with them, trying to imagine how a 'hanging kirigami mobile for kids' could become a nanoscale spring for measuring forces or interacting with cells," said Melina Blees, a former physics graduate student and now a postdoctoral researcher at the University of Chicago.
Using a sheet of graphene, the researchers were able to create a "spring" that functions as a flexible nanoscale transistor. The hinge was opened and closed 10,000 times while staying completely intact and elastic. The spring could be triggered by a force comparable to that of motor proteins. This innovation could lead to new technology that could be implanted into human cells or the brain for sensing.
"It's one thing to read about how strong graphene is; it's another thing entirely to crumple it up and watch it recover, or to stretch a spring dramatically without tearing the materials," Blees said. "It's not every day that you get to develop a feel for a nanoscale material, the way an artist would."
The findings were published in a recent edition of the journal Nature.
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