Materials: grapheme
When plastics were first realised as materials of mass-production in the Fifties, they completely changed the world. Not just through their benefits in all manner of products, buildings, clothes and packaging but these brightly-coloured pellets extracted from oil changed the way the world actually looked. At the time, artists, writers and in particular film makers viewed our future world through the lens of plastics, movies like Forbidden Planet, 2001 and even kids cartoons such as The Jetsons painted an optimistic view of the world decorated with this new wonder material.
As we enter 2014, we are presented with a different palette for the future through advanced materials. A world where data-driven materials, shape-changing materials, lightweight and composite materials promise to take us into a new stage of evolution. Carbon fibre, silicon, titanium, aerogel – and increasingly the reuse of natural materials – promise to deliver a future with new potential for our environment, our planet and beyond, with one of the most recent and potentially significant being graphene.
Graphene is only one atom thick, making it the thinnest material in the world
The first thing to say about graphene is that I don’t get it. It’s super-strong, super-light, superconductive, transparent, but incredibly dense. But what is really hard to understand is how something so unimaginably thin – one atom thick and therefore delicate – can be used for applications that require extreme strength (expert help on this later).
First off, to produce graphene is very simple in principle. To get a sense of its structure, you only have to draw a line with a graphite pencil. Although this line might not be graphene, it will contain many, many layers of graphene. Being the world’s thinnest material graphene would, in relative terms, take 300,000 layers of its 2D hexagonal structure of graphite to create the thickness of the paper you would be drawing on. If you want to understand one of its key properties, that of it being conductive, then connect two pencil lines with electrodes, a battery and small LED.
Although discovered in 1962, graphene received its status as a wonder material following groundbreaking experiments by Andre Geim and Konstantin Novoselov, at the University of Manchester. The pair received the Nobel Prize for physics for their research of the 2D material in 2010 by using Sellotape to slowly peel off layers of graphite to leave a single layer of graphene. Now established as the strongest material ever measured – some 200 times stronger than structural steel – with the potential to be used in anything from composite materials and electronics, to digitised clothing and food packaging. One of its most recent developments was in March 2013, when scientists at Zhejiang University led by Professor Gao Chao, developed a hybrid of two ‘wonder’ materials by combining graphene with an aerogel structure to develop the lightest solid in the world weighing just 0.0019 kg per cubic decimetre. As a comparison, magnesium, which is the lightest commercially used metal, weighs in at 1.73 kg per cubic decimetre.
The key to understanding graphene in real applications was explained to me by Line Kyhl, a PhD student at the iNano centre at Aarhus University, Denmark: ‘To get from this ultra-thin material to something you can use in constructions can take different approaches. An example is to use it as a coating for ordinary steel to make it more resistant against corrosion, or to mix smaller flakes of graphene into plastics to completely change their properties, making very strong lightweight plastics, although this is a field not fully explored yet. Another issue is that it is currently very challenging to produce graphene at a large a scale to be used in these applications.’
As a result, the race is clearly on to find new applications for this astonishing material and, like many advanced materials, the first applications have already appeared in sports products, with Head making a tennis racquet that uses graphene to redistribute the weight. Consumer electronics companies are also exploring applications such as a transparent conductive base for ultra-thin electronic components for touch screens or smart watches.
One thing that is for sure, is that graphene has the potential to do what most other advanced materials can’t – change the way the world looks. If plastics were responsible for changing the visual language of the world in the Fifties and Sixties with bright and bold colour in unusual shapes, then graphene could do the same in the 21st century by creating unimaginably thin, unimaginably tall, unimaginably strong, products and structures.
