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Building blocks

While it is yet to fulfil its promise as a true wonder material, the imaginative and widespread use of graphene nevertheless is capable of bringing a revolution in material science

Building blocks
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Ever since its discovery in 2004, graphene has been hailed as the greatest scientific breakthrough of the 21st century. A material harder than diamond, the hardest known substance, and 200 times stronger than steel and a million times thinner than human hair, it surely is a wonder. Its discovery was an ecstatic moment for scientists and engineers around the world, as it was believed that it would almost enable the production of the kind of technologies that we're used to seeing in sci-fi movies. And here we are, more than a decade and a half later and nothing that wonderful has happened. Not even close. Has the scientific community overstated the magic of this wonder material? No, not exactly. With more than 10,000 research papers in graphene-related subject areas published worldwide every year, graphene has still managed to withhold the awe of scientists. Perhaps, we are at the cusp of the graphene age.

So what is this wonderful graphene? It is a man made substance with godly characteristics. It is a single layer possessing a thickness of the order of the size of an atom of graphite. Yes, graphite; that humble pencil lead. The only difference is that graphite has a three-dimensional crystal structure but graphene is a two-dimensional material. It is a sheet of carbon atoms arranged in a honeycomb structure. Amazing as it sounds, graphene was simply extracted from a piece of graphite using a common adhesive tape. The tape was pasted on graphite and pulled gently several times to obtain a thin imprint on it. This is graphene, the wonder material. This material when tested for its electrical, thermal, elastic properties turned out to be a marvel. It is almost a perfect electrical conductor with negligible resistivity, it's an amazingly good conductor of heat, it exhibits exemplary strength and toughness, and its elasticity can be estimated from the fact that only six gram of graphene is sufficient to cover a football field.

The discovery of graphene and its extraordinary properties was widely celebrated by the scientific community when it was awarded the Nobel Prize in 2010. And it immediately generated huge expectations ranging from replacement of silicon in common electronics to invention of a space elevator. So, if this substance has been known for so long then what is holding it back from taking over the market? It is the lack of economically feasible and efficient mass production. It needs to be way ahead of its competitor materials like silicon in all respects to become a household name. We can't have enough sticky tape to make all the electronics and space elevator to the heavens. Fortunately, there has been a lot of research taking place on new techniques of mass production in recent years with promising results for instance industry has succeeded in developing high-quality graphene foil from plastic waste.

How exactly is graphene a game-changer? It has enabled the production of many utilities with extraordinary features, which may readily be commercialised. An Italian helmet manufacturing company, Momo design, has floated a range of helmets coated with graphene. The presence of graphene improves the distribution of any impact force, making it safer. It also dissipates heat faster than conventional materials, making the helmet cooler. Also, an American company called Real Graphene has created a graphene-enhanced lithium battery that can cut phone charging time from an hour and a half to 20 minutes. It has a longer life than conventional lithium batteries and generates less heat. Another Italian company, Italcementi, has proposed graphene-infused concrete, which could lead to doing away with wiring in buildings, as the building material is already highly conductive on its own. graphene's high thermal conductivity would enable walls to dissipate heat, potentially eliminating the need for air conditioning in hot countries. We are already on the verge of a freshwater crisis. graphene has a solution to this too. Scientists have devised a low-cost, energy-efficient and environment-friendly technology using graphene electrodes for desalination of seawater.

Meanwhile, researchers at the Chalmers University of Technology (Sweden) have shown how the coating surface of medical implants with 'vertical graphene flakes' makes them resistant to bacterial infections. This could limit the use of antibiotics and lower the chances of implant rejection by the host body. In fact, graphene has proved to be a boon for medicine and healthcare. Graphene infused flexible circuits can be worn as smart patches on the skin, or on contact lenses, that can, in turn, make digital health monitoring easier. Talking of very recent research in medicine, graphene oxide derivatives are being studied as biosensors to detect cancerous cells and other diseases in the human body and also as media for targeted drug delivery. Not to forget face masks, they have become a necessity in times of COVID-19 pandemic, but irresponsible disposal of these has led to the secondary transmission of the disease. Scientists have devised a solution to this by inventing graphene masks with an antibacterial efficiency of 80 per cent, which can be enhanced to almost 100 per cent upon exposure to sunlight.

With mass production on the horizon, research has come a long way. We can expect to see markets flooded with graphene-based products sooner than later. Although we'll have to wait for more ambitious, Elon Musk kind proposals, graphene promises to bring a revolution in material science. The only limit to graphene is our imagination.

The writer is an assistant professor, Department of Physics, DAV College, Bathinda. Views expressed are personal

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