A new era has begun
The tradition of using materials to name important eras – such as the Stone, Bronze and Iron Ages – underlines how they have the power to transform the way that we live, work, fight and travel.
Now we are entering a new era, one that is distinguished not by the composition of materials but their dimensions and whether they have a thickness of just one molecule, or even a single atom, according to Andre Geim, Regius Professor and Royal Society Research Professor at the University of Manchester.
On 29 September 2016, at the Museum of Science and Industry, Andre Geim will discuss his remarkable contribution to this two dimensional material revolution with me as part of the Manchester Science Festival.
Over the decades, he has built up a reputation for his playful approach to science, which has seen him levitate his pet hamster with a powerful magnetic field and create novel adhesives based on gecko feet.
His commitment to being adventurous in the lab (‘search, not re-search’) is what attracted many of his collaborators to join his world-leading team at Manchester’s National Graphene Institute, such as Kostya Novoselov, who shared the Nobel prize with Andre in 2010 for their groundbreaking work on graphene.
The 2D breakthrough came when their team used sticky tape to clean graphite, the stuff of pencils, which has a crystal structure consisting of layers of carbon atoms.
Andre explained how, at first, they found out that you could ‘easily’ make graphite transparent, already suggesting it was extremely thin. Then they discovered that they could even turn graphite into graphene, consisting of a single layer of carbon atoms arranged in a puckered hexagonal lattice, which exhibits tremendous stability, strength and electrical conductivity.
As Andre told us at the launch of our exhibition on this revolution, Wonder Materials: Graphene and Beyond, this ‘eureka moment’ lasted the best part of six months.
Since his team first isolated graphene more than a decade ago, companies have discovered how to mass produce it in quantities ranging from square metres to metric tons.
And the list of potential commercial uses has grown to take advantage of its ‘very unusual properties’, from being invisible to the human eye to being 200 times tougher than steel.
The first uses range from using it as an additive to improve plastics, enhance the durability of paint, boost the performance of batteries, and improve the efficiency of light bulbs.
These are, says Andre, among hundreds of ‘dirty and first’ applications ‘when properties of graphene are only marginally utilised’.
Now we are entering the Age of 2D Materials in earnest, as more advanced applications emerge for graphene and substances that are its 2D ‘brothers and sisters’, including hexagonal boron nitride, fluorographene and so on, along with novel composites consisting of 2D materials assembled in a Lego-like fashion. ‘This is a snowball which is going to roll and roll,’ says Andre.
As an example of the many emerging uses of graphene, a Manchester team led by Andre’s wife and co-worker Irina Grigorieva recently reported in the journal Nature Communications the creation of graphene balloons that can withstand huge pressures, greater than those at the bottom of the deepest ocean.
These nano bubbles – which can be fashioned from other 2D materials – routinely form when handling graphene and are usually regarded as a nuisance. Now, in the light of this work, they could be of value as tiny pressure machines capable of showing how molecules react under extreme pressures as high as 200 megapascals, or 2,000 atmospheres.
In other work, Andre and a Manchester group led by postdoctoral researcher Radha Boya have discovered how to create the smallest ever water and gas pipes.
Materials containing tiny capillaries and cavities are widely used in filtration, separation and many other technologies. These materials are usually found by luck or accident rather than design, let alone at atomic-scale precision, and have proved extremely useful.
In this new research, reported this month in Nature, the team extracted graphene from graphite the usual way, then focused on what was left behind in the graphite crystal: a cavity as small as an atom across.
The properties of materials at this truly atomic scale are expected, as a result of quantum effects, to be quite different from those we are familiar with at everyday dimensions. Still, they were surprised when they observed that water flowed through these cavities with little friction and at high speed, as if the channels were many thousands times wider.
Radha Boya commented how such capillaries ‘were never imagined, even in theory. New filtration, desalination, gas separation technologies are kind of obvious directions, but there are so many others to explore’.
Such atomic scale cavities can be atomically smooth or rough, water-loving or water-hating, insulating or conductive, electrically charged or neutral; the list goes on. And, as Andre puts it, ‘making something useful out of an empty space is certainly cute. Finding that this space offers so much of new science is flabbergasting’.
In another new application to emerge recently, graphene has been used by Andre’s team, working with colleagues in Germany and Austria, to create a ‘quantum prison’ where electrons behave like the electrons in an atom (as a result, it is often called an ‘artificial atom’) .
However, their properties can be tuned and, as a consequence, might find uses in quantum computers, which may be able to solve problems which are not practically feasible with the usual kind.
Image credit: Copyright – Nobel Media AB; Photo – Yana Audas