Graphene sponge developed at MIT is ten times stronger than steel
Image credit: MIT
Three-dimensional graphene ten times stronger than steel but 95 per cent lighter has been developed by American researchers.
The supermaterial is one of the first successful experiments translating graphene, a one-atom-thick layer of carbon atoms, into 3D with satisfying results.
The invention by a team from the Massachusetts Institute of Technology, has been described in an article in the latest issue of the journal Science Advances.
Two-dimensional materials such as graphene have been known for their outstanding properties. However, their extreme thinness has so far rendered these materials less appealing for industries such as construction, aerospace or car making. Scientists have therefore been trying to create three-dimensional versions of these materials but the results have so far been disappointing.
The MIT team solved the problem by using a high-resolution multi-material 3D printer to compress flakes of graphene into a sponge-like configuration. These microscopically structured layers proved remarkably strong thanks to the enormous surface area in proportion to their volume.
The researchers, led by Markus Buehler, the head of MIT’s Department of Civil and Environmental Engineering, also created computer models of the new materials, which suggested that their extraordinary properties are likely to be due to the sponge-like structure rather than because of the graphene itself.
Such a conclusion is promising as it suggests it might be possible to create materials with similarly outstanding properties out of ordinary materials as well.
“You could either use the real graphene material or use the geometry we discovered with other materials, like polymers or metals,” Buehler said. “You can replace the material itself with anything. The geometry is the dominant factor. It’s something that has the potential to transfer to many things.”
Buehler explained that what happens to their 3D graphene material resembles what would happen with sheets of paper. Paper has little strength along its length and width, and can be easily crumpled up. But when made into certain shapes, for example rolled into a tube, suddenly the strength along the length of the tube is much greater and can support substantial weight. Similarly, the geometric arrangement of the graphene flakes after treatment naturally forms a very strong configuration.
Using cheaper materials would of course reduce the cost, widen the range of processing methods and add other properties that graphene might not have.
In fact, the researchers believe the structures could also work on a macro scale, providing extra sturdiness to concrete and other building materials. A bridge built using such configurations would be extra strong and extremely lightweight at the same time. This approach would have the additional benefit of providing good insulation because of the large amount of enclosed airspace within it, the researchers said.
Because the shape is riddled with very tiny pore spaces, the material might also find application in some filtration systems, for either water or chemical processing.