By: Elton Santos, Queen’s University Belfast

CarbonScientists have found a way to make carbon both very hard and very stretchy by heating it under high pressure. This “compressed glassy carbon”, developed by researchers in China and the US, is also lightweight and could potentially be made in very large quantities. This means it might be a good fit for several sorts of applications, from bulletproof vests to new kinds of electronic devices.

Carbon is a special element because of the way its atoms can form different types of bonds with each other and so form different structures. For example, carbon atoms joined entirely by “sp³” bonds produce diamond, and those joined entirely by “sp²” bonds produce graphite, which can also be separated into single layers of atoms known as graphene. Another form of carbon, known as glassy carbon, is also made from sp² and has properties of both graphite and ceramics.

But the new compressed glassy carbon has a mix of sp³ and sp² bonds, which is what gives it its unusual properties. To make atomic bonds you need some additional energy. When the researchers squeezed several sheets of graphene together at high temperatures, they found certain carbon atoms were exactly in the right position to form sp³ bonds between the layers.

By studying the new material in detail, they found that just over one in five of all its bonds were sp³. This means that most of the atoms are still arranged in a graphene-like structure, but the new bonds make it look more like a large, interconnected network and give it greater strength. Over the small scale of individual graphene sheets, the atoms are arranged in an orderly, hexagonal pattern. But on a larger scale, the sheets are arranged in a disorderly fashion. This is probably what gives it the combined properties of hardness and flexibility.

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GrapheneScientists have created a durable catalyst for high-performance fuel cells by attaching single ruthenium atoms to graphene.

Catalysts that drive the oxygen reduction reaction that lets fuel cells turn chemical energy into electricity are usually made of platinum, which stands up to the acidic nature of the cell’s charge-carrying electrolyte. But platinum is expensive, and scientists have searched for decades for a suitable replacement.

The ruthenium-graphene combination may fit the bill, says chemist James Tour, a professor of computer science and of materials science and nanoengineering at Rice University, whose lab developed the material. In tests, its performance easily matched that of traditional platinum-based alloys and bested iron and nitrogen-doped graphene, another contender.

“Ruthenium is often a highly active catalyst when fixed between arrays of four nitrogen atoms, yet it is one-tenth the cost of traditional platinum,” Tour says. “And since we are using single atomic sites rather than small particles, there are no buried atoms that cannot react. All the atoms are available for reaction.”

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AirplaneA team of researchers has created a new material that could be used in microscopic sensors, also known as microelectromechanical systems [MEMS], for devices that are part of the Internet of Things.

The technological future of everything from cars and jet engines to oil rigs, along with the gadgets, appliances, and public utilities comprising the Internet of Things will depend on these kinds of microscopic sensors. These sensors are mostly made of the material silicon, however, which has its limits.

“For a number of years we’ve been trying to make MEMS out of more complex materials” that are more resistant to damage and better at conducting heat and electricity, says materials scientist and mechanical engineer Kevin J. Hemker of Johns Hopkins University’s Whiting School of Engineering.

Most MEMS devices have internal structures that are smaller than the width of strand of human hair and are shaped out of silicon. These devices work well in average temperatures, but even modest amounts of heat—a couple hundred degrees—causes them to lose their strength and their ability to conduct electronic signals. Silicon is also very brittle and prone to break.

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New research out of the University of Florida shows a new 3D printing technology that could lead to strong, flexible, affordable medical implants.

Through this new process for the use of 3D printing and soft silicone, the researchers believe items that millions of patients use could be more easily manufactured, ranging from implantable bands to soft catheters to slings.

This from the University of Florida:

These kinds of devices are currently molded, which can take days or even weeks to create customized parts designed to fit an individual patient. The 3D-printing method cuts that time to hours, potentially saving lives. What’s more, extremely small and complex devices, such as drainage tubes containing pressure-sensitive valves, simply cannot be molded in one step.

The new method allows them to be printed.

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GrapheneA quantum probe based on an atomic-sized “color center” in diamonds has let researchers observe the flow of electric currents in graphene.

Made up of a lattice of carbon atoms only one atom thick, graphene is a key material for the electronics of the future. The thin carbon material is stronger than steel and due to its flexibility, transparency, and ability to conduct electricity, holds great promise for use in solar cells, touch panels, and flexible electronics.

No one has been able to see what is happening with electronic currents in graphene, says Lloyd Hollenberg, professor at the University of Melbourne and deputy director of the Centre for Quantum Computation and Communication Technology.

According to Hollenberg, this new technique overcomes significant limitations with existing methods for understanding electric currents in devices based on ultra-thin materials.

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Two discoveries could provide a simple and effective way to “stencil” high-quality 2D materials in precise locations and overcome a barrier to their use in next-generation electronics.

In 2004, the discovery of a way to isolate a single atomic layer of carbon—graphene —opened a new world of 2D materials with properties not necessarily found in the familiar 3D world. Among these materials are a large group of elements—transition metals—that fall in the middle of the periodic table.

When atoms of certain transition metals, for instance molybdenum, are layered between two layers of atoms from the chalcogenide elements, such as sulfur or selenium, the result is a three-layer sandwich called a transition metal dichalcogenide. TMDs have created tremendous interest among materials scientists because of their potential for new types of electronics, optoelectronics and computation.

“What we have focused on in this paper is the ability to make these materials over large areas of a substrate in precisely the places we want them,” says Joshua Robinson, associate professor of materials science and engineering at Penn State. “These materials are of interest for a variety of next-generation electronics, not necessarily to replace silicon, but to augment current technologies and ultimately to bring new chip functionality to silicon that we never had before.”

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A team of researchers from the University of Michigan has developed a self-healing, water-repellant coating that is hundreds of times more durable than its counterparts.

The researchers believe this development could help enable waterproof vehicles, clothing, rooftops, and other surfaces – something that current hydrophobic coatings struggle with due to their fragility.

“Thousands of superhydrophobic surfaces have been looked at over the past 20 or 30 years, but nobody has been able to figure out how to systematically design one that’s durable,” says Anish Tuteja, co-author of the study. “I think that’s what we’ve really accomplished here, and it’s going to open the door for other researchers to create cheaper, perhaps even better superhydrophobic coatings.”

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GrapheneA team of researchers at the University of Manchester – where graphene was first discovered and won the Nobel Prize – created a graphene-oxide membrane for desalination. The newly developed sieve can turn seawater into drinking water, demonstrating graphene’s ability to filter common salts from water, leading to affordable desalination technology.

Prior to this research, graphene-oxide molecules have garnered significant attention from the scientific community, demonstrating their potential to filter our small nanoparticles, organic molecules, and even large salts. However, researchers have not been able to use a graphene-oxide membrane in desalination technologies, which require very small sieves, until this development.

This from the University of Manchester:

Previous research at The University of Manchester found that if immersed in water, graphene-oxide membranes become slightly swollen and smaller salts flow through the membrane along with water, but larger ions or molecules are blocked.

The Manchester-based group have now further developed these graphene membranes and found a strategy to avoid the swelling of the membrane when exposed to water. The pore size in the membrane can be precisely controlled which can sieve common salts out of salty water and make it safe to drink.

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GrapheneGraphene could offer a new way to cool tiny chips in phones, computers, and other gadgets.

“You can fit graphene, a very thin, two-dimensional material that can be miniaturized, to cool a hot spot that creates heating problems in your chip,” says Eva Y. Andrei, a physics professor at Rutgers University. “This solution doesn’t have moving parts and it’s quite efficient for cooling.”

As electronics get smaller and more powerful, there’s an increasing need to for chip-cooling solutions. Researcher show in a paper published in the Proceedings of the National Academy of Sciences that using graphene combined with a boron nitride crystal substrate creates a very efficient cooling mechanism.

“We’ve achieved a power factor that is about two times higher than in previous thermoelectric coolers,” says Andrei.

The power factor refers to the effectiveness of active cooling. That’s when an electrical current carries heat away, as shown in this study, while passive cooling is when heat diffuses naturally.

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Corroded pipelinesFor many centuries, lead was the favored material for water pipes due to its malleability. However, the health hazards associated with ingesting lead were not fully understood until the late 1900s. Now, with a massive water infrastructure that utilizes lead pipes and instances of corrosion and leaching causing development and neurological effects in young children consuming tainted water, researchers from Washington University in St. Louis are researching the potential impact of replacing lead pipes.

According to the research team, digging up lead pipes to replace them with copper piping would not only be extremely expensive, but potentially dangerous. The team developed a new way to model and track where dislodged lead particles might be transported during the replacement process.

“We all know lead is not safe, it needs to go,” says Pratim Biswas, past ECS member and chair of Energy, Environmental and Chemical Engineering at the School of Engineering & Applied Science. “This is the first comprehensive model that works as a tool to help drinking-water utility companies and others to predict the outcome of an action. If they have the necessary information of a potential action, they can run this model and it can advise them on how best to proceed with a pipe replacement to ensure there are no adverse effects.”

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