29 July 2007
29 July 2007
Researchers at Northwestern University have fabricated a new type of stiff, strong and lightweight paper that they hope will find use in a wide variety of applications.
In a paper to be published July 26 in the journal Nature, researchers led by Rod Ruoff, John Evans Professor of Nanoengineering in the Robert R. McCormick School of Engineering and Applied Science, report on the development of graphene oxide.
Ruoff's research team was the first to develop graphene-based composite materials, which was reported in Nature last year. Graphene -- a sheet of carbon only one atom thick -- has the potential to serve as the basis of an entirely new class of materials.
“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 high 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, which could be infused to create hybrid materials containing polymers, ceramics or metals, where such composites would perform much better than existing materials.