Graphene was one of the breakthrough science stories of the new millennium. Hailed as a wonder material of the future, its remarkable physical properties have transformed the way we think about materials.
Introduction
First isolated at the University of Manchester in 2003 by a team led by Andre Geim and Kostya Novoselov, Graphene is the first single-layer material ever discovered.
At only one atom thick it is the thinnest material possible, yet it is also the strongest—200 times stronger than steel. It’s flexible, transparent and conducts electricity and heat incredibly well, giving this small material huge potential.
The isolation of graphene made a huge splash in science media because it has so many outstanding properties, and speculation about some of the potential applications for this wonder material ran wild.
Credit: © Nobel Media AB, Photo Yana Audas
What is graphene?
Graphene is a two-dimensional crystal sheet of carbon atoms, arranged in a hexagonal lattice, so through a very powerful microscope, it looks a bit like chicken wire.
Credit: Sarah Haigh, University of Manchester and Quentin Ramasse, EPSRC SuperSTEM Laboratory, Daresbury
Graphene is made from ordinary graphite. You may have made graphene yourself when drawing with a graphite pencil, although even the thin flakes made as we draw with a pencil are usually too thick to be graphene. A key thing to understand about graphene is that it is really small. A one millimetre-thick piece of graphite is made up of 3 million layers of graphene stacked on top of one another. A sheet of graphene is just one of these layers.
Before it was first isolated in 2003, it was already known that graphite was made up of incredibly thin sheets of carbon atoms, and painstaking attempts to get down to that elusive single sheet go back more than a century. Scientists predicted that a single layer of carbon atoms would have fascinating properties, but suspected that it couldn’t possibly be stable.
How was graphene isolated?
Scientists already knew about the theoretical existence of materials comprising single atomic layers but no-one had previously been able to isolate one.
Since 1859 scientists had been trying to achieve a single layer using chemical and mechanical methods involving expensive and specialised equipment. However, when a single sheet of graphene was finally isolated, it was done using a cheap and familiar piece of equipment—ordinary sticky tape.
Sticky tape was already used to clean samples of graphite ready for experiments and examination by stripping off the top layer to expose the clean graphite beneath. The light bulb moment came when Andre and Kostya’s group wondered if, when they were throwing away the used pieces of sticky tape with graphite residue on them, that they might in fact be throwing away graphene. As the anecdote goes, they fished a piece back out of the bin, put it under a microscope, and were delighted to see really thin flakes of graphite right there on the tape. Peeling and repeeling made it possible to get right down to transparent films of graphene.
The actual sticky tape dispenser used in that story was donated to the Science and Industry Museum by Kostya Novoselov in 2006, and is shown above. It’s a fascinating object because it is so familiar and ordinary, yet it was pivotal to a Nobel Prize-winning breakthrough in materials science. It’s a prime example of the sort of everyday equipment that is part of a science story, but often lost over time precisely because it is so mundane. As Kostya has said, ‘Science should be fun and you don’t always need to do expensive multi-million-dollar experiments to be on the cutting edge of research,’ a point that this sticky tape dispenser really emphasises.
But isolating a single sheet of graphene was just the start.
Using graphene
Graphene has opened up a whole new world of scientific exploration into single-layer materials. The hard work began immediately after Andre and Kostya isolated graphene. They did extensive experiments and research to investigate the electrical properties of graphene and went on to win a Nobel Prize for the publication of their research.
One of the initial problems with graphene was how to produce it commercially, as it wasn’t practical to produce the microscopic flakes using sticky tape at the scale required. It’s one thing to have small samples for the lab, but another to produce enough for manufacturing. However, since graphene was first isolated, several companies have now discovered how to mass produce it in quantities ranging from square metres to metric tons.
There have been several commercial applications for graphene already, which involve using it as an additive to enhance materials like rubber and plastic to make them lighter, stronger and more durable. Some examples are graphene-enhanced trainers, a tennis racket and a fishing rod, with just a small amount of graphene increasing the performance of these materials. Some other early uses were to enhance the durability of paint, or make lightbulbs use less energy and last longer.
The future of graphene
Graphene really fires the imagination when it comes to thinking about what we might do with it. Its many properties, like the fact that it is invisible to the human eye, yet 200 times stronger than steel, bring to mind amazing new technologies. It’s the most conductive material discovered, giving it great potential for electronics applications, and because it’s also stable and non-reactive, it could have medical uses. It has even been imagined that it could one day enable science fiction-like technology, from nano robots to cyborg brain implants.
Looking ahead, there is hope that graphene’s extraordinary properties could play an important role in reducing our impact on the environment. Graphene makes it possible to make things lighter and stronger and therefore use less energy, it is being proposed for enabling batteries with a much better performance, and it has potential to transform the way we think about filtration, which could reduce pollution.
Graphene is the ultimate multi-tasking material, and there are many different ways in which it can help us use less energy, reduce carbon emmissions and improve the environment.
Related blog posts and resources
- Sarah Baines, A Brief History of Stuff Episode 2: Sticky tape, SMG podcast
- Sarah Baines, The story of graphene in objects, SMG Journal
- Sarah Baines, Eco-friendly wonder materials, Science and Industry Museum blog
- Roger Highfield, Supercomputer peels away graphene's sticky secrets, Science Museum blog
- Roger Highfield, Secret of scientific creativity revealed by Andre Geim, Science Museum blog
