World’s thinnest material stretches, bends, twists

Graphene gets manipulated under the microscope

MATERIALS IMITATE ART A series of cuts can produce unique shapes out of paper (top row) and graphene (bottom, shown in micrographs), which has a millionth the thickness of paper. Researchers created a stretchable sheet (left), a pyramid (center) and a spiral (right).

DENVER– A technique inspired by Japanese paper arts allows scientists to manipulate single-atom-thick sheets of carbon as if they were pieces of paper, researchers announced March 5 at a meeting of the American Physical Society. The team stretched, twisted and bent the sheets under the microscope.

Graphene, just one carbon atom thick, is under intense study due to its remarkable strength and electric conductivity. But it is hard to isolate graphene because it is produced on a substrate. Cornell physicist Melina Blees and colleagues managed to isolate graphene by dissolving away a layer of aluminum beneath it.

Once Blees had liberated individual graphene sheets, she decided to apply some tricks from kirigami: a variation of origami that utilizes cutting, as paper snowflakes do. After etching a series of cuts into the graphene, Blees found she could stretch the material like an accordion, twist it in spirals and bend it like a hinge under an optical microscope.

Customized graphene structures eventually could be used to weigh small objects, Blees says, or to measure the electrical signals zipping through a living cell.

FROM PAPER TO GRAPHENE The cutting technique used to create paper snowflakes can be used on single-atom-thick sheets of carbon, which then stretch, as shown in this video taken through a microscope at 40 times magnification.
Courtesy of M. Blees/Cornell; adapted by Ashley Yeager

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