Graphene – the sky is not the limit

Graphene-enhanced materials – the sky is not the limit
Ansell and Walsh are exploring opportunities to apply their research to cubesats and satellites, hoping to be able to expose graphene-enhanced materials to many more challenging environments and see how it behaves © Ecole Polytechnique

SEQ spoke to UCLan’s Dr Robert Ansell and Professor Robert Walsh about the role of graphene-enhanced materials in the space and aerospace sectors.

In 2017 in the first experiment of its kind researchers at the University of Central Lancashire (UCLan) explored the practical applications of exploiting graphene in the UK space industry. They did this by launching specially designed graphene-enhanced materials – enhanced carbon fibre – into near space using high altitude balloons.

By comparing a graphene-enhanced carbon fibre to a standard carbon fibre casing, the team, led by aerospace engineer Dr Darren Ansell and his colleague Professor Robert Walsh, professor of astrophysics at the university, were able to test how both react to extreme conditions high above the Earth. They will then compare the results to determine how graphene can be utilised in space.

Enduring aerospace challenges

Graphene has been hailed as the world’s first 2D material. In particular it is ultra-light, yet incredibly strong. Speaking to SciTech Quarterly, Ansell explained: “Graphene has a lot of different physical properties, and that makes it a very exciting material. But while many of these properties have been explored under laboratory conditions, we wanted to take that and move it forward and apply it.

“There are enduring challenges in space and aerospace around mass savings, making things stronger and more robust. In the aerospace sector particularly, new materials which lead to reductions in weight also therefore lead to environmental benefits because they stand to reduce fuel consumption whilst maintaining the required strength. As such, they are the key drivers.”

In addition to potential weight savings, graphene also has interesting thermal properties, and so work needs to be done to understand how the material acts as an insulator or conductor of heat, both of which are of interest to the space and aerospace sectors, where it is necessary to protect against engine heat and recirculate heat away from certain areas.

“Graphene can also be electrically conductive too,” Ansell added, “depending on what form of graphene you are using. There is thus potential to replace cabling, or antennas, on aircraft with graphene-enhanced materials.

“Indeed, a typical aircraft has numerous computers on board, as well as literally miles of cabling. Substituting those things alone with graphene-enhanced materials would result in a reduction in weight significant enough to necessitate a major change to the way aircraft are manufactured.”

Disruptive technology

Walsh added: “Looking at ways to reduce the mass of an aircraft is pretty standard fare. If you can potentially reduce the mass by up to 20% then that is a significant saving.

“In some respects, the potential applications for graphene are simply confined by our own thought processes about how to actually introduce this material into the environments in which we are working,” he concluded.

Graphene, of course, stands to disrupt numerous sectors alongside space and aeronautics, including health, energy and energy storage technologies, transport, and more. However, it is perhaps worth remembering that this material is relatively new and, as such, the advances being made in any of these sectors are tentative.

It is therefore refreshing to see the type of experiment conducted by the team at the University of Central Lancashire, in which Walsh and Ansell sent graphene-enhanced materials 35 kilometres into the sky, taking place.

Discussing the experiment, Walsh said: “We want the UK to become more involved in the application of graphene as a disruptive material, and we are continuing to work with industry to ensure that they become as excited about graphene as we are.”

How does pressure and temperature affect graphene?

Walsh and Ansell’s experiment built on the researchers’ prior experience of working with key players in the space sector, including the UK Space Agency and NASA. The team wanted to see how graphene behaved in an environment of low pressure and low temperature.

Walsh told SEQ: “The UK Space Agency provided us with a small grant to undertake a series of high altitude balloon experiments. Payloads of graphene-enhanced materials and others of non-graphene-enhanced materials are employed so as to be able to compare and contrast how these particular materials behave in this environment, where the atmospheric pressure is some 90% less than that which we experience on the ground. In addition, at that altitude, the temperatures goes down to about -60°C.

“Of course, these conditions can be can reproduced on the ground, but we wanted to actually fly this material for the first time and show you can put graphene into that environment.”

The balloon flights lasted around 2.5 hours, which means that the researchers were also able to expose these materials to the environment for much longer than they would have been otherwise.

Walsh went on: “The graphene-enhanced payload was around 20% lighter. It had the same electronics and tracking and so on as the other non-graphene enhanced casing.”

Once the team had recovered the balloons after the flights they didn’t see any immediate difference between the payloads, and they are now examining the data more thoroughly.

The experiment was, Walsh said, more of an exercise in highlighting the fact that there are graphene enhanced materials which could be used in space-based applications.

Ansell added: “Of course, these applications depend on how the graphene-enhanced material has been manufactured and what its original purpose is, because there are so many different physical properties to graphene that can be exploited when it is added to a material. The particular carbon fibre we used was particularly enhanced for its electrical performance rather than its strength.

“But we immediately saw a weight saving, and so that benefit is also directly apparent. And we are now conducting a series of ground tests to investigate sample pieces of material, which will provide us with additional data.”

The materials’ journey saw them experience a change of 70 degrees in temperature (from around 10°C on the ground, to around -60°C in the air) and a significant change in atmospheric pressure. As a laminate material, carbon fibre can have negative reactions to this kind of low pressure, and so the UCLan experiment is an important step to better understanding how these materials behave in such environments (non-destructive techniques such as ultrasound will be used on the materials to investigate what, if any, effects the temperature and pressure changes have had).

Barriers to a wider industry use of graphene

Ansell and Walsh work closely with the UK’s National Graphene Institute, having previously conducted experiments using graphene on aircraft wings. And, as previously mentioned, graphene – and indeed other 2D materials – stand to act as a disruptive force in a wide variety of industries and sectors.

Yet, one of the biggest barriers here is the lack of graphene-enhanced materials suppliers in Britain today. As Ansell highlighted, many manufacturers look to the big markets, such as carbon fibre, and so there is now a need for them to turn their attention to graphene-enhanced materials so as to assist the research community in conducting experiments into the potential applications of this material. And, of course, this research will only serve to boost industry participation and the wider rollout of graphene applications across sectors, thus driving further demand across the value chain. As a consequence, there will be costs involved in investing in new technologies, and there is a sense that the required amount of confidence needed to foster this investment remains lacking.

“There is no shortage of ideas of how to use graphene,” Ansell told SEQ. “The problem lies in being able to manufacture it, certainly in the quantities and the sizes that make it useful, and this is one of the most significant barriers we are experiencing at the moment.

A national graphene strategy for the UK

Wash added: “There is the possibility of many different sectors wanting to use graphene in many different ways. However it is difficult to make that jump, and a downside at the moment is that there are very few companies who are actually looking at how they can potentially introduce graphene into their systems. Hopefully that will increase, and experiments like our balloon launches and the conversations that are starting to take place with companies can help to further whet that appetite.

“We are also starting to look at whether the UK needs a full graphene strategy in different disciplines and across different industrial areas. This could address how graphene can be introduced and exploited as much as possible in Britain moving forwards.”

For Ansell, to achieve the momentum required to push forwards with a national strategy to reach the necessary level, success stories have to be highlighted and the technology has to be demonstrated, even if this is at a small scale, in order to convince people it is worthwhile. And, the researcher said, this is now starting to come together in the UK. Walsh also highlighted that graphene now receives a mention in the UK’s Industrial Strategy.

Britain: the home of graphene

Britain is, of course, the ‘home of graphene’. It was in Manchester that Professors Andre Geim and Konstantin Novoselov developed the material for which they received the Nobel Prize, and it is in Britain that this material has received a substantial amount of public money in order for it to be developed further towards commercially-viable applications across sectors.

Within this landscape, Ansell and Walsh have always placed a distinct focus on the application on graphene in the UK. “We see it as being very important for various manufacturing industries and this material could give us a competitive edge on the global market place,” Ansell said. “And there has been a significant amount of public money put into graphene in the UK as well, so it is important that we see a return on that.”

With the potential impacts of Brexit now drawing closer, it is difficult, if not impossible, to predict how this will affect both the UK science base and its innovative industries. But, according to Walsh, Britain nevertheless retains its potential to be a world leader in the field of graphene and related applications. And, as such, it is now more important than ever for the UK to retain those currently working in the field – whom Walsh referred to as “the best people in the world” – because UK industry could benefit immeasurably if there is a serious push in terms of understanding the benefits that this material can bestow and the importance of it being a part of R&D across a range of industries.

Future priorities

In addition to further investigating the data gathered from the balloon experiments, Ansell and Walsh hope to continue working alongside the National Graphene Institute and their other partners, focusing on the space and aerospace industries.

“We are also currently exploring opportunities to apply our research to cubesats and satellites, and we hope to be able to expose graphene-enhanced materials to many more challenging environments and see how it behaves,” Wash said. “We want to help foster a dialogue on how, commercially, the UK space industry can be the first to apply graphene-enhanced approaches to spacecraft.”

Ansell added: “From an aerospace point of view, we also want to get more graphene technology innovations into demonstrator platforms. In the past, we have focused on aircraft wings and aircraft structures. Moving forwards, we want to explore whether we can start integrated other forms of graphene that are now emerging into an aircraft.

“We have used UAVs because they are simple to fly and are therefore a good way for us to demonstrate some of the work we have been doing. Indeed, we took one to the Farnborough Air show in 2016, where we were able to demonstrate a graphene wing in flight to over 100,000 people over three days. We will be looking for more opportunities like that as we move forward. And this will also be in relation to other areas, too, such as graphene batteries and antennas which can be integrated and demonstrated relatively easily.”

 

Dr Darren Ansell

Space and Aerospace

Engineering Lead

School of Engineering

Professor Robert Walsh

Jeremiah Horrocks Institute

University of Central Lancashire (UCLan)

dansell@uclan.ac.uk

RWWalsh@uclan.ac.uk

www.uclan.ac.uk/

This article will appear in SciTech Europa Quarterly issue 26, which will be published in March, 2018

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