Two recent findings in the world of graphene illustrate how graphene continues to be a subject worth following. Subjects in their infancy give rise to all kinds of interesting and unexpected discoveries, and in the case of graphene these discoveries occur with astonishing frequency. However, the two latest findings, one from the very birthplace of graphene science, Manchester University, and one from Tianjin University in China, show in different ways how the miracle material just gets better and better.
The news fresh from Manchester is that graphene has the ability to heal itself when punctured. Now, its probably too soon to be throwing away the bicycle repair kit, but the 11 page research paper filed by a team including the Nobel laureate Konstantin Novoselov, suggests that graphene has the ability to re-knit itself, closing any holes in its surface by either reattachment or inclusion. The paper, simply title “Graphene re-knits its holes,” suggests.
Nano-holes, etched under an electron beam at room temperature in singlelayer graphene sheets as a result of their interaction with metalimpurities, are shown to heal spontaneously by filling up with either non-hexagon, graphene-like, or perfect hexagon 2D structures. Scanning transmission electron microscopy was employed to capture the healing process and study atom-by-atom the re-grown structure. A combination of these nano-scale etching and re-knitting processes could lead to new graphene tailoring approaches.
The potential benefit of this finding is yet to be fully explored. We are after all talking about nano-holes and not the sort found in hill farmers’ cardigans. However, the notion of a self-healing material is certainly exciting and something that I am sure will attract a lot of investor interest. Whether the UK team can capitalize on their finding and keep the benefits of the discovery within the European region remains a separate concern.
Moving over to China the latest finding to have been published from the team at Tianjin University suggests that it is better to flatten a carbon nanotube to produce graphene that it is to unzip it. The technique uses acid oxidation to attack the C-C bonds at the very edges of the flattened nanotube. Rather like a squashed piece of macaroni, the flattened carbon nanotube yields graphene nanoribbons (GNRs) with edges that are much more uniform than those produced by unzipping. The technique results in a better quality GNR and its simplicity and scalability means that it could easily be adopted by industry.
According to Tawfique Hasan of Cambridge University, a Royal Institute Fellow of Engineering with expertise in graphene, the technique could well become the industry’s standard method of production.
‘This method vastly improves the quality and yield,’ he says. ‘This simple and ingenious strategy may well represent the very first scalable production of uniform and straight GNRs.’