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Is graphene the next carbon fibre?

Graphene in the bike industry
Max Glaskin
9 Jul 2015

Discovered in a pencil smudge, could graphene be the new super material that transforms the bike industry?

On the face of it, graphene is a simple material. It’s a single layer of carbon atoms 0.3 nanometres thick – a million times thinner than the paper of this magazine. Yet it’s 150 times stronger than steel and 20% more elastic. It conducts electricity better than copper or gold, at a speed of one million metres per second. It sheds heat fast. It’s transparent as well as totally impermeable, and it should have the same impact in the 21st century that carbon fibre did in the 20th and steel in the 19th. No wonder the two materials scientists at Manchester University who discovered it in 2003, Andre Geim and Konstantin Novoselov, were fast-tracked to a Nobel Prize and knighthoods. But what does this have to do with bikes?

Graphene’s early adopters

The first cycling products containing graphene are starting to hit the market. Vittoria uses graphene in its latest carbon Qurano rims (see p20) and Catlike too uses it in its range-topping Mixino helmet. Custom carbon framebuilder Richard Craddock of Craddock Cycles says, ‘There’s a lot of excitement about graphene right now, but these are only the first forays. Like every new material, its full potential isn’t yet known but it’s most likely the maximum benefit is not as a substitute for carbon but as an enhancement. I’d use it when it’s proven.’

Paul Wiper, research associate at the National Graphene Institute at Manchester University, says, ‘Graphene can improve the mechanical properties of a composite, as it can share the strain when added to the epoxy resin matrix and make it stiffer. You have to get the balance right, though. A lot of graphene, say 10 or 20% of the matrix, would make it really stiff but it would also be brittle.’

His colleagues are currently perfecting the use of graphene in composite frames for aerospace, and Spanish car manufacturer Spania already includes it in its GTA supercar chassis. So could bicycle frames be next? ‘There’s no reason at all why it couldn’t be used in bike frames and I’m sure someone’s working on them already,’ Wiper predicts. Vittoria has such faith in graphene, it’s put its money where its mouth is. ‘I happened to have dinner five years ago with the founder of Directa Plus, one of the first graphene factories in Europe, and I came up with the idea of using graphene in our products,’ says Vittoria president Rudie Campagne. ‘Then we decided to invest in them, to be at the cutting edge.’

Vittoria claims by using graphene in the new Qurano carbon wheels it has increased spoke-hole strength and lateral stiffness of the rim by up to 30%. But above all, Campagne enthuses, ‘The improved heat dissipation of graphene reduces the accumulated temperature of the rim [under braking], keeping it well below the threshold where carbon fibre would start to  disintegrate.’

Adding graphene to carbon is not quite as simple as adding sugar to your coffee, though. Directa Plus supplies graphene to Vittoria as ‘nano-platelets’, which are just three to seven atoms thick. ‘The big challenge was to achieve a near-perfect dispersion of graphene in the master batch of epoxy resin for the prepreg carbon sheets,’ says Campagne.

Slice of inspiration

Graphene bicycle

‘People had speculated for decades that graphene existed within allotropes of carbon materials such as graphite, coal and diamond, but nobody had known how to make it as a single two-dimensional layer,’ says Wiper. In an inspired moment, Geim and Novoselov had started with a smudge of crystalline graphite – effectively a pencil mark – which is composed of multiple, stacked layers of graphene, and using sticky tape they stripped away some of the graphite. Being curious, they did it again and again, until finally they isolated a single layer – pure graphene. Then they tested it.

‘Usually when you make materials thinner and thinner, their properties deteriorate,’ says Geim himself. ‘But with graphene we found things only got better.’

Labs around the world now make graphene in many ways, with different purities, varying sample sizes and batch quantities. For example, Catlike says it uses nano-fibres to maintain the strength of its Mixino helmets, which are now 10g lighter than previous models. Others are using it in the form of nano-ribbons, and Samsung and Sony claim to have invented ways to make continuous sheets. What is perhaps surprising, though, is that it’s not overly expensive. You can buy a kilo of nano-platelets for less than £150. As more versions of the material are created, it’s certain that the use of the word ‘graphene’ in marketing material will create confusion for consumers. It will be tricky to ascertain whether a product that claims to be ‘graphene-enhanced’ really does contain the sub-microscopic material, or whether it’s doing any good. It’s a loophole the unscrupulous could exploit.

‘A lab could test the material to see if it performs as claimed, but you’d have to do a chemical test to make sure graphene is present,’ Wiper says. And as graphene exists within most forms of carbon, even coal dust, it could be Trades Description Act hell. But in the right hands, its promise for the cycling industry is vast. Potential uses for graphene include preventing corrosion on exposed parts such as rims, chainrings and spokes, or, if embedded in carbon components, graphene nano-fibres could conduct electricity or even transfer data. That would reduce cabling for electronic shifting and bike computers. Alternatively it could form strain gauges in carbon hubs, cranks, pedals, chainrings or shoe soles, where its nano-fibres would reduce complexity and potentially cut the price of power meters.

Nano-diamonds have already been coated with graphene to create super-lubricants, which could eliminate almost all friction from bearings, and super-bright, graphene-enhanced LEDs are promised as soon as next year. A graphene supercapacitor can potentially store more energy than any existing batteries, so therefore substantially lighter electronic shifting components would also be made possible. What’s more, trials of embedding graphene electrodes in polypropylene fibres are underway too, so there’s even some potential for future inclusion in clothing garments. It’s hypothetical at this stage but there could be a point in time when your jersey and shorts become smart, sensing your heart rate, blood pressure, temperature, perspiration rate and even the activity of individual muscles. It really does seem like its uses and benefits have few bounds.

‘Graphene is obviously so new that its applications are only just starting to be studied,’ says Campagne. ‘It will take many years of fundamental and applied study to come up with great new improvements of existing products or new applications and refinements. The journey is only just beginning.’

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