July 12, 2012
Probably the single most fascinating development in materials science in the past decade has been the discovery of carbon structure known as graphene, a sheet of carbon atoms arrayed in hexagons just a single atom thick. Like carbon nanotubes before it, the material boasts a variety of unique and interesting properties that could make it useful in a range of different industries.
Only recently discovered for practical purposes, however, researchers are still struggling with how to produce the material en masse and in ways that will be able to make effective use of its unusual properties.
Now, though, Technology Review reports that researchers might have found another fascinating characteristic that could make graphene dramatically more practical: the material will actually readily heal itself.
Patching up holes.
One of the biggest problems in working with graphene is that, because the material is only a single atom thick, it is relatively fragile and easily tears or forms holes in its structure. These gaps can inhibit some of the more useful characteristics of the material, particularly those pertaining to its electrical properties.
It was while examining exactly these properties that a team from the University of Manchester’s and the Engineering and Physical Sciences Research Council’s SuperStem Laboratory discovered this new twist on the modern wonder-material, according to the BBC.
Led by Konstantin Novoselov, one of graphene’s initial discoverers, the group was attempting to attach metal contacts to sheets of graphene and found that the materials would frequently tear in the process. However, while examining the graphene through electron microscopes they noticed that the holes begin to bond with metal strips or, if it were present, any available carbon atoms.
“It just happened that we noticed it,” Quentin Ramasse, a researcher at the SuperStem laboratory and co-author of the study, told the BBC. “We repeated it a few times and then tried to understand how that came about.”
As it turned out, the graphene was capable of more than that just filling holes in its structures with other materials.
The carbon was more than willing to bond with metals, and when introduced to hydrocarbons, chains of carbon with attached hydrogen, would create imperfect connections with the carbon atoms. When introduced to pure carbon, though, the material was actually able to reconstruct perfectly formed layers of graphene, repairing the gap entirely.
While self-repairing materials might sound like it would have almost limitless applications, people must remember that graphene is still a single layer of carbon. However, what this new discovery might make possible is a new way of actually creating graphene and shaping it into useful structures.
Because of carbon’s reactive nature, it has been difficult to attempt to scale up production processes of graphene to commercially useful levels. But by carefully controlling the introduction of metals and pure carbon into existing graphene sheets, researchers how they could essentially allow the materials to assemble itself.
“If you can drill a hole and control that ‘carbon reservoir’, and let them in in small amounts, you could think about tailoring edges of graphene or repairing holes that have been created inadvertently,” Ramasse explained. “We know how to connect small strips of graphene, to drill it, to tailor it, to sculpt it, and it now seems we might be able to grow it back in a reasonably controlled way.”
Variety of applications
Graphene has already been incorporated into a number of different technologies with interesting effects. The Engineerreports that a new production method developed at the University of California at Los Angeles could reliably produce high-speed carbon-based electronics that make use of the highly conductive properties of graphene.
In an entirely separate area, researchers at the Massachusetts Institute of Technology have found a way to easily desalinate water using graphene, and ongoing engineering research looks like to discover further applications.