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July 25, 2007

Graphene oxide paper created

Researchers at Northwestern University have fabricated graphene oxide paper which is remarkably stiff and strong yet lightweight material and should find use in a wide variety of applications.

"The mechanical, thermal, optical and electrical properties of graphene are exceptional," says Ruoff. "For example, the stiffness and strength of these graphene-like sheets should be superior to all other materials, with the possible exception of diamond."

To form the graphene oxide paper, the group oxidized graphite to create graphite oxide, which falls apart in water to yield well-dispersed graphene oxide sheets. After filtering the water, the team was able to fabricate pieces of graphene oxide 'paper' more than five inches in diameter and with thicknesses from about one to 100 microns, in which the individual micron-sized graphene oxide sheets are stacked on top of each other.

"I have little doubt that very large-area sheets of this paper-material could be made in the future," Ruoff notes.

In addition to their superior mechanical properties as individual sheets, the graphene oxide layers stack well, which could be key to the development of other materials.

"You can imagine that these microscale sheets may be stacked together and chemically linked, allowing us to further optimize the mechanical properties of the resulting macroscale object," Ruoff says. "This combination of excellent mechanical properties and chemical tunability should make graphene-based paper an exciting material."

Ruoff sees a wide variety of application for graphene oxide paper, including membranes with controlled permeability, and for batteries or supercapacitors for energy applications. Graphene oxide paper could also be infused to create hybrid materials containing polymers, ceramics or metals, where such composites would perform much better than existing materials as components in, for example, airplanes, cars, buildings and sporting goods products.

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