What is graphene and what can it do?
If you’ve been anywhere near a science journal over the past decade or so, you’ll have come across some form of superlative about graphene – the two-dimensional wonder material that promises to transform everything from computing to biomedicine.
There’s a lot of hype about graphene’s applications, thanks to a handful of remarkable properties. It’s 1 million times thinner than a human hair but 200 times stronger than steel. It’s flexible but can act as a perfect barrier, and is an excellent conductor of electricity. Put all of that together and you have a material with a multitude of potentially revolutionary applications.
What is graphene?
Graphene is carbon, but in a one-atom thick honeycomb lattice. If you reach back into your old chemistry lessons, you’ll remember materials composed entirely of carbon can have drastically different properties, depending on how its atoms are arranged (different allotropes). The graphite in your pencil lead, for example, is soft and dark compared to the hard and transparent diamond in your engagement ring. Human-made carbon structures are no different; the ball-shaped Buckminsterfullerene acts differently to the coiled arrangements of carbon nanotubes.
Graphene is made of a sheet of carbon atoms in a hexagonal lattice. Of the above, it is closest in form to graphite, but whereas that material is made from two-dimensional sheets of carbon held layer-upon-layer by weak intermolecular bonds, graphene is only one-sheet thick. If you were able to peel a single, one-atom-high layer of carbon from graphite, you would have graphene.
The weak intermolecular bonds in graphite make it appear soft and flakey, but the carbon bonds themselves are robust. This means a sheet solely composed of those carbon bonds is strong – about 200 times more so than the strongest steel, while at the same time being flexible and transparent.
Graphene has been theorised for a long time, and accidentally produced in small quantities for as long as people have been using graphite pencils. Its main isolation and discovery, however, is pinned on the work of Andre Geim and Konstantin Novoselov, in 2014 at the University of Manchester. The two scientists reportedly held “Friday night experiments”, where they would test ideas outside of their day jobs. During one of these sessions, the researchers used scotch tape to remove thin layers of carbon from a lump of graphite. This pioneering piece of research eventually led to the commercial production of graphene.
After they won the Nobel Prize in Physics in 2010, Geim and Novoselov donated the tape dispenser to the Nobel Museum.
What can graphene be used for?
One important thing to note is that scientists are developing all sorts of materials based around graphene. This means it’s probably better to think about “graphenes”, in the same way we’d think about plastics. Essentially, the advent of graphene has the scope to lead to a whole new category of material, not just one new material.
In terms of applications, research is being done in areas as wide-ranging as biomedicine and electronics to crop protection and food packaging. Being able to modify the surface property of graphene, for example, could make it an outstanding material for drug delivery, while the material’s conductivity and flexibility could herald a new generation of touchscreen circuitry or foldable wearable devices.
The fact that graphene is capable of forming a perfect barrier to liquids and gasses means it can also be used with other materials to filter any number of compounds and elements – including helium, which is an exceptionally difficult gas to block. This has a range of applications when it comes to industry, but could also prove very useful to environmental needs around water filtration.
The multifunctional properties of graphene open the doors to an enormous amount of composite uses. While a lot of thought has gone into how it can boost pre-existing technologies, continual advancements in the field will eventually lead to whole new areas that would have previously been impossible. Could we see a whole new class of aerospace engineering emerge? What about augmented reality optical implants? From the looks of it, the 21st century is when we’ll find out.