CAR PAINT WITH GRAPHENE GETS ICE OFF RADAR DOMES

Ribbons of ultrathin graphene, combined with polyurethane paint meant for cars, can keep ice off of sensitive military radar domes, report scientists.

The Rice University lab of chemist James Tour, in collaboration with Lockheed Martin, developed the compound to protect marine and airborne radars with a robust coating that is also transparent to radio frequencies.

The new compound provides a thin, robust ice-melting coat for marine, airborne and other uses. The active element consists of carbon nanotubes "unzipped" into ribbons. (Credit: Tour Group/Rice University)
The new compound provides a thin, robust ice-melting coat for marine, airborne and other uses. The active element consists of carbon nanotubes “unzipped” into ribbons. (Credit: Tour Group/Rice University)

Bulky radar domes (known as “radomes”) like those seen on military ships keep ice and freezing rain from forming directly on antennas. But the domes themselves must also be kept clear of ice that could damage them or make them unstable.

This task is usually accomplished with a metal framework that supports and heats ceramic alumina (aluminum oxide), Tour says. But these materials are heavy, and metallic elements must be installed far from the source of radio signals to keep from interfering.

“It’s very hard to deice these alumina domes,” Tour says. “It takes a lot of power to heat them when they’re coated with ice because they’re very poor conductors.”

Enter graphene, the single-atom-thick sheet of carbon that both conducts electricity and, because it’s so thin, allows radio frequencies to pass unhindered. Spray-on deicing material that incorporates graphene nanoribbons would be lighter, cheaper, and more effective than current methods, Tour says.

“This started when (Lockheed Martin engineer) Vladimir Volman saw a presentation by Yu Zhu, a postdoc in my lab at the time,” he says. “Volman had calculated that one could pass a current through a graphene film less than 100 nanometers thick and get resistive heating that would be great for deicing. Zhu was presenting his technique for spraying nanoribbons films and Volman recognized the potential.”

Pristine graphene transmits electricity ballistically and would not produce enough heat to melt ice or keep it from forming, but graphene nanoribbons (GNRs) unzipped from multiwalled carbon nanotubes in a chemical process invented by the Tour group in 2009 do the job nicely, he says.

When evenly dispersed on a solid object, the ribbons overlap and electrons pass from one to the next with just enough resistance to produce heat as a byproduct. The effect can be tuned based on the thickness of the coating, Tour says.

A waveguide frames a graphene nanoribbon film for testing. (Credit: Tour Group/Rice University)
A waveguide frames a graphene nanoribbon film for testing. (Credit: Tour Group/Rice University)

THE RIGHT PAINT

In initial experiments, the team led by Volman and Zhu spray-coated a surface with soluble GNRs. “They said it works great, but it comes off on our fingers when we touch it,” Tour says.

He found the solution in a Houston auto parts store. “I bought some polyurethane car paint, which is extremely robust. On a car, it lasts for years. So when we combined the paint and GNRs and coated our samples, it had all the properties we needed.”

Lab samples up to two square feet were assembled using a flexible polymer substrate, polyimide, which was spray-coated with polyurethane paint and allowed to dry. The coated substrate was then put on a hotplate to soften the paint, and a thin GNR coat was airbrushed on. When dried, the embedded ribbons became impossible to remove. Tour says the researchers have also tried putting GNRs under the polyurethane paint with good results.

The 100-nanometer layer of GNRs—thousands of times thinner than a human hair—was hooked to platinum electrodes. Using voltage common to shipboard systems, the compound was sufficient to deice lab samples cooled to -4 degrees Fahrenheit within minutes. Further experiments found them to be nearly invisible to radio frequencies.

Tour says the availability of nanoribbons is no longer an issue now that they’re being produced in industrial quantities.

“Now we’re going to the next level,” he says, noting that GNR films made into transparent films might be useful for deicing car windshields, a project the lab intends to pursue.

Volman suggests the material would make a compelling competitor to recently touted nanotube-based aerogels for deicing airplanes in the winter. “We have the technology; we have the material,” he says. “It’s very durable and can be sprayed on to heat any kind of surface.”

The Lockheed Martin Corp. through the LANCER IV program, the Air Force Office of Scientific Research, and the Office of Naval Research supported the research.

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South Korean engineers find graphene electrodes can recharge in 16 seconds

Quantum Hydrogen on Graphene

Yes, one day, you too may be able to fully recharge your plug-in vehicle’s battery in the amount of time it takes to decelerate down one of those runaway truck ramps. Assuming your brakes actually work, of course.

Engineers at South Korea’s Gwangju Institute of Science and Technology are researching the concept of graphene supercapacitors and how they can be applied to plug-in vehicle technology, Technology Review says. A simplified explanation is that the engineers have created an extremely porous version of graphene, turned it into a powder (which makes its surface area larger) and packed the powder into a cell.

The fun part is that the new graphene electrode was tested to provide almost as much charge as a fully recharged lithium-ion battery, with the amazing benefit of only needing about 16 seconds to recharge, raising interesting possibilities for applying the technology to a regenerative braking system. And the electrode was tested 10,000 times and didn’t suffer capacity reduction. Cornell University published a version of the study here.

The idea of using graphene, a crystalline form of carbon, for automotive technology, is continuously being researched. Earlier this year, researchers from South Korea, Case Western University and University of North Texas said they discovered that a graphene-coated cathode may generate a greater battery current than a cathode covered with the more expensive but more traditional platinum. And in 2011, University of Technology Sydney researchers created a type of graphene “paper” that is stronger, lighter and less dense than steel. Such widespread use would enable automakers to cut vehicle weight and boost fuel efficiency as a result.

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Graphene producer’s shares jump by 40% in market debut

Shareholders pile in to buy a slice of Applied Graphene Materials, which has found a way to mass produce graphene

Graphene is already used in tennis rackets, with future applications including aircraft bodies and m

Graphene is already used in tennis rackets, with future applications including aircraft bodies and membranes for DNA sequencing.

A British firm which has found a way to produce industrial quantities of graphene, the wonder material expected to revolutionise the fields of medicine and manufacturing, saw its share price rise 40% during its stock market debut on Wednesday.

Shareholders piled in to buy a slice of Applied Graphene Materials (AGM), which is based in Cleveland and was spun out of Durham University, in a float that was more than two times oversubscribed.

Graphene, a substance isolated by Nobel prize-winning scientists at the University of Manchester in 2004, is a one-molecule-thick layer of graphite that is 20 times stronger than diamond and conducts electricity 20 times better than copper. It has already been used in tennis rackets and future applications range from aircraft bodies to membranes used in DNA sequencing.

Graphene is difficult to make in large quantities, but AGM, which raised £11m by selling a 42% stake, has found a way to mass produce the material in powder and is working with companies including Dyson and Procter & Gamble to develop commercial uses for the material.

“This funding will allow us to begin the next phase of development and to strengthen relationships with our partners,” said chief executive John Mabbitt. “Applied Graphene Materials is now well positioned to meet the growing global appetite for graphene as a wonder material of the 21st century.”

The float on London’s Aim market for smaller companies saw shares pop from the initial placing price of 155p to 216p by the close of the first day’s trading, valuing the company at £36m. AGM is forecast to become profitable in 2017.

Founder and technical director Karl Coleman, professor of inorganicchemistry at Durham University, retains a 10% stake, having reduced his holding from 24% before the float. Early backer IP Group, which invests in patent-based businesses, has reinvested and retains a 20% stake.

AGM will use the capital raised on Aim to expand the capacity of its Teesside production facility from one tonne a year to eight over the next 18 months. The company’s 10-strong workforce will also increase, with engineers and scientists recruited to develop commercial applications for its products.

Most graphene production relies on natural supplies of graphite, which has to be mined, but AGM has found a way to produce it using carbon atoms sourced from ethanol. Its product can then added to resins, plastics, oils and lubricants.

Dyson wants to use graphene in the plastic casing for its vacuum cleaners, because of its strength, and because its ability to conduct electricity reduces static, which in turn helps the machine suck in more dust.

Added to paints, graphene could help protect the hulls of boats from rust and, as a dry lubricant, reduce drag as the ship moves through water.

While the UK pioneered the discovery of graphene, Asian companies have made the greatest efforts to commercialise it, with electronics giant Samsung leading the way.

“We [the British] are good with the initial materials, but other people are better at seeing applications … We have to be careful with graphene, otherwise it is one of those things that we just let go,” said Mabbitt.

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Bulletproof Graphene

Graphene, the one atom thick layer of graphite, has proven to be an exciting substance in the development of advanced materials.

Graphene sheets are formed from hexagonal carbon atoms linked by covalent bonds. Each sheet is considered as a single molecule since it is one atom thick. Graphene possesses high strength because of the strength of covalent bonds between each atom.

The electrical property of graphene is faster than any known material. Graphene has potential applications in medicine, energy, computing, and many other fields.

A recent breakthrough for graphene applications is in materials for bulletproof vests developed by combining carbon nanotubes with graphene. In 2012, researchers from the University of Wollongong (UOW) developed a new graphene-based material which is tougher than substances such as spider silk and Kevlar that are widely employed in bulletproof vests.

Ballistic/bulletproof vests employ layers of strong fibers to absorb the energy of the bullet, and deform it, to disperse its energy throughout the vests. They minimize the force of the bullet in one area, and prevent the bullet from penetrating the textile matrix and body.

Sometimes, bullets may penetrate some fiber layers of the vest. However, the energy from the bullet is absorbed by larger fiber areas as the bullet starts to deform. To this date, Kevlar and spider silk are still regarded as the toughest fibers employed in ballistic vests.

UOW researchers developed the composite material by adding equal parts of graphene and carbon nanotubes to the polymer. This graphene material was then processed into fibers using a wet-spinning method.

Could graphene replace spider silk and kevlar in bulletproof vests?

The resulting fiber was found to be exceptionally tough due to the mixture of equal parts of carbon nanotubes and graphene. According to researchers, this super tough fiber can find potential applications in bulletproof vests and advanced composite reinforcements.

Researchers have proved that this graphene-based composite material functions more like carbon nanotubes, a common toughening agent employed in polymer composites.

The research team insist that the composite material is relatively inexpensive, and can be produced in large quantities.

Strength and toughness are two important properties of materials. The requirement of high strength and toughness is based on the applications. Ballistic applications such as bullet-proof vests require more toughness than strength, as the vest absorbs the energy of the bullet.

This research presents a novel graphene composite material that is extremely tougher than any other fibers to date. The mixture of graphene oxide particles to carbon nanotubes in solution-spun polymer creates an exceptionally strong fibrous material which finds applications not only in battlefield protection, but also in advanced materials construction.

As carbon nanotubes are capable of conducting electricity, researchers hope that this composite material can also be used in actuating materials and electrical energy storage in the future.

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Discovering graphene was only the start – its potential is almost limitless

Discovered by two brilliant scientists playing around with sticky tape on a Friday afternoon, graphene promises to become even more important than the ubiquitous silicon that has powered the computer age.

It was Andrei Geim and Kostya Novoselov at Manchester University who realised that they could create layers of graphene just one molecule thick by repeatedly sticking and peeling back Scotch tape from flakes of graphite – the stuff found in pencils.

Graphene is composed of a two-dimensional crystal lattice of pure carbon and is quite simply a superlative material of immense potential – the thinnest and strongest substance known to science and something like 100 times stronger than steel by weight.

More importantly graphene – described as “atomic chickenwire” because of its honeycomb molecular structure – exhibits interesting physical, electrical and optical properties. It is a superb conductor of heat and electricity, it is one of the most stretchable materials and yet is almost transparent.

Its potential uses are almost limitless, ranging from flexible electronics and wearable computers and electronic devices, to highly-efficient solar panels and super-fast mobile phones. Yet, at the heart of graphene is pure carbon, the non-toxic, atomic essence of all living things.

Using graphene to make condoms may seem like something of a joke, but not if you are looking for an effective barrier to HIV and other sexually transmitted diseases, especially in those parts of the developing world hit hardest by Aids.

Graphene is highly stretchable, ultra-thin, non-toxic and very strong, so there is no doubting its commercial potential as a new kind of material for super-safe sheaths of the future, which you may not be able to feel or see.

Other potential uses in the developing world include a material to desalinate seawater or to filter dirty water for drinking. Graphene is even being touted as an explosives detector and a super-strong fibre for bullet-proof vests and body armour.

The discovery and creation of graphene was only the beginning. The next stage will be to find ways of exploiting its full potential, which may well lead to practical uses we can only have dreamed of in the past.

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Bill Gates condom challenge ‘to be met’ by graphene scientists

graphene institute

The five-floor National Graphene Institute is set to open in 2015, creating 100 jobs

Safer condoms will be one of the first products developed at the new National Graphene Institute in Manchester.

The Bill and Melinda Gates Foundation has awarded scientists $100,000 (£60,000) to create stronger, thinner condoms from the new “wonder material”.

The substance will be mixed with latex to produce a material which will encourage use by “enhancing sensation”.

Graphene, the thinnest, strongest material known, was first isolated at the University of Manchester in 2004.

It has more often been linked to potentially revolutionising products such as smartphones and broadband.

Its discovery won Manchester-based scientists Sir Andre Geim and Sir Kostya Novoselov the Nobel Prize for Physics in 2010.

First ‘everyday use’

The charity has offered the Grand Challenges Explorations grant to the Manchester research team to develop new composite materials for condoms, which it wants to make more desirable in order to increase global usage.

Dr Papa Salif Sow, senior program officer on the HIV team at the foundation, said a “redesigned condom that overcomes inconvenience, fumbling or perceived loss of pleasure would be a powerful weapon in the fight against poverty”.

Dr Aravind Vijayaraghavan, who will lead the researchers, said that since it was isolated, “people have wondered when graphene will be used in our daily life”.

“Currently, people imagine using graphene in mobile phone screens, food packaging and chemical sensors.

“If this project is successful, we might have [an everyday] use which will literally touch our everyday life in the most intimate way.”

The National Graphene Institute at the University of Manchester is being established with a £23m grant from the European Regional Development Fund.

The five-floor building is set to open in 2015, creating 100 jobs.

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Graphene Comes to Nanopore Gene Sequencing

Nanopore sequencing—the ability to sequence a strand of DNA by reading its electronic signature as it slithers through a nanoscale pore in a membrane— has always held great promise, but it has been frustratingly difficult to realize its full potential. There have been attempts to boost the faint signal produced as the DNA passes through the nanopore. Other research has aimed to slow the speed at which the DNA passes through the nanopore to improve the measurement. Some researchers have even created a molecular motor that doesn’t just slow the DNA down but controls it’s movement through the nanopore.

Now researchers at the Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland have turned to the wonder material graphene as the membrane.

The original technique on which this latest iteration of nanopore sequencing is based suffered from the nanopore frequently clogging up as well as a general lack of precision in the measurements.

“We thought that we would be able to solve these problems by creating a membrane as thin as possible while maintaining the orifice’s strength”, said Aleksandra Radenovic from the Laboratory of Nanoscale Biology at EPFL in a press release.

The EPFL research, which was published in the journal Nature Nanotechnology (“Detecting the translocation of DNA through a nanopore using graphene nanoribbons”),  showed that the typical insulating membrane that is used nanopore schemes is as thick as 15 DNA bases—the chemical rungs of DNA’s ladder-like helix. But graphene is only 0.335 nm thick, which is equal to the spacing between two bases in a DNA chain, making it possible to individually analyze the passage of the DNA bases as the squiggle through the nanopore.

While the researchers believe that graphene will ultimately lead to a higher precision nanopore sequencing technique, the speed at which the DNA molecule pass through the nanopore remains a problem. In only 5 milliseconds 50 000 DNA bases can pass through. So the signal given off by the DNA passing through the pore is too faint to read.

“However, the possibility of detecting the passage of DNA with graphene nanoribbons is a breakthrough as well as a significant opportunity”, added Radenovic in the release.

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