The Nobel prize for physics was awarded this year to two scientists working in Manchester for their work on developing graphene and creating a method to make it in large quantities.
Graphene is an individual layer in graphite – the material pencil ‘leads’ are made from so the chances are that you have some of this amazing nanomaterial lying around you right now.
Despite being just one atom thick and looking somewhat like chicken-wire, graphene is stiffer than diamond and more than 100 times stronger than steel but it can be stretched like rubber. Despite its extreme thinness, it is very dense and impermeable to gases or liquids. These properties mean that it has a future in the development of body armour, aircraft fuselages and crack-proof television screens.
It is also an excellent conductor of electricity and so could be used in the future in place of silicon to make faster transistors in computer chips – very useful considering the desire for ever smaller but more powerful computing gadgets. It could also be used to make the next generation of solar panels and touch-screens and
One low-tech method that the scientists used to create layers of graphite up to only 10 graphene sheets thick is quite extraordinary. Using just normal sticky tape they peeled off layers from pencil ‘lead’. Repeating this ‘scotch-tape method’ produced thinner and thinner layers.
Teaching idea and resource
Most GCSE specifications require students to learn about giant covalent structures including diamond and graphite and apply their knowledge of their structure to explain their properties and uses. Graphene could be used as an example. Students could be told about its structure and then asked to predict why it has the useful properties of it being lightweight, strong, transparent and a good electrical conductor.
This idea is contained in a graphene PowerPoint slide which could be used as a plenary to a lesson. More able students could then go on to predict uses of the material.
You could demonstrate to the students the principles of the method the scientists used to isolate sheets of graphite by drawing onto a piece of plastic with a pencil and then using sticky tape to peel off a layer. Explain to the students that a layer of graphite 1mm thick actually consists of three million layers of graphene stacked on top of one another. They can then use their knowledge about the structure of graphite to explain why the layers come apart so easily. You could also have a go at using the method the scientists actually used by following the demonstration in the video linked below. It claims that they can form a graphene sheet using this method but I’m not so sure…
Interview with one of the prize winners, Andre Geim on his research
Article on the RSC’s Chemistry World blog about the discovery
Video demonstrates how to create a graphene layer using the ‘scotch-tape’ method.