The Hype About Graphene
Graphene is amazing. It is incredibly light, flexible, conductive – and it happens to be the strongest known material in the world. Recent material discoveries mean graphene could soon begin to revolutionise everyday objects. An i-Pad for example, may soon resemble something more like a piece of paper that can be folded up and stashed in your back pocket.
Many scientists believe that graphene is the most important synthetic material created since plastic revolutionised the world of materials more than 100 years ago. Its potential applications seem almost limitless. Researchers have discovered that the material’s electrical and magnetic behaviour could lead to flexible electronics such bendable i-Phones or wallpaper-thin televisions that can be rolled up like posters. Other developments to date include a graphene transistor that could enable much faster computing, ultra strong composites that could replace carbon fibers, highly conductive nanomaterials for electronics, lightning-powered skyscrapers as well as super-efficient, long-lasting batteries. Graphene could even help catch drug cheats at the Olympics! Researchers are developing a system whereby graphene is able to detect a molecule of a drug within minutes. So how exactly does graphene gain these super powers and what’s the catch?
Graphene is made out of carbon, specifically a one atom thick sheet of it. The material is so thin that it is effectively two-dimensional. Appearing transparent to the naked eye, it is also incredibly light with a square meter of graphene weighting less than a gram. It is incredibly strong for two main reasons. Firstly, graphene is made entirely of carbon atoms. Each carbon atom is surrounded by six other carbon atoms resulting in a highly stable honeycomb structure, which remains solidly locked in place by strong covalent bonds between the atoms. Secondly, unlike a 3D material, graphene’s extremely simple, two-dimensional structure basically leaves little room for material weakening defects to appear.
Graphene was initially hyped as something as a wonder material when its discovery won the Nobel Prize in 2010. Since then however, graphene has failed to reach its hyped-up potential – mainly because of difficulties in scaling graphene up to a workable dimension. Until recently, scientists have been manufacturing pure graphene in its pristine form by mechanically peeling a graphite crystal. The process is costly and not very practical except for producing very small quantities of the material for research purposes. To scale the material up and create larger, more practical sizes of graphene sheets, scientists rely on a process called ‘chemical vapour deposition’ (CVD). CVD is a process whereby single layers of graphene are grown inside a high-temperature furnace. The resulting sheets aren’t uniform in their surface structure but appear like a patchwork of smaller patches – referred to as grains – which are stitched together over a thin layer of copper. In theory, scientists believed these larger streets would retain the ultra high strength properties of the pure, individually peeled graphene samples but in practice this has not been the case until now. A team of scientists of Columbia University recently discovered that the weaknesses in the larger, patchwork sheets of graphene are not caused by seams or the grain of the material but rather the chemicals used to remove the copper substrate after the grains have formed. The team then developed a new process using a different etchant to remove the copper substrate, leaving the resulting graphene sheets undamaged.
Because CVD techniques are already capable of producing graphene sheets as large as a TV screen, improvements to the production process could quickly open the door to potential engineering developments in flexible screen or stronger, more advanced materials that incorporate graphene.
Materia can see how the hype is growing. Graphene could for instance mean the business cards you hand out in the future could update themselves and perhaps even send messages and emails. In the built environment, the heavy solar panels currently installed on roofs could transform into a kind of solar wallpaper that can be rolled up and pasted onto any exterior surface. Your evening paper could contain movable images that refresh themselves along with newspaper ads that play the commercials you avoid on television – because no technology is perfect of course!
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