• AI tool speeds thermoelectric generator design while matching leading prototype performance
• TEGNet cuts simulation time from thousands of seconds to fractions of one
• Cheaper waste-heat harvesters could follow, although manufacturing still has to prove itself

Researchers in Japan have built an AI tool that can design thermoelectric generators far faster than standard simulation methods, pointing to cheaper ways of turning waste heat into electricity.

TEGNet was developed by Takao Mori and colleagues at Japan’s National Institute for Materials Science (NIMS) and the University of Tsukuba.

In the paper published in Nature, it predicted generator performance with more than 99% accuracy while using only 0.01% of the computing time needed by commercial finite-element solvers.

Acting as a fast emulator

Thermoelectric generators turn heat differences directly into electricity, with no turbines or moving parts.

They already power spacecraft, remote sensors and some isolated infrastructure, but cost and middling performance have kept them out of wider use in factories, refineries, vehicles and electronics.

Designing thermoelectric generators is slow because researchers have to balance materials, geometry, temperature conditions, electrical resistance and heat flow.

A conventional solver has to solve coupled physics equations again and again, which can take days or weeks for broad searches.

TEGNet learns from those simulations, then acts as a fast emulator. The paper says a typical material simulation took about 2,237 seconds in COMSOL, while TEGNet produced the same type of result in about 0.25 seconds.

The researchers used the AI to improve two types of generators, one built from stacked layers of different materials and another made from paired semiconductor materials that work together to produce electricity.

Lab-built prototypes reached conversion efficiencies of 9.3% and 8.7%, respectively, putting them among strong reported results for that temperature range.

That still doesn’t make thermoelectrics a cure-all. Heat-to-electricity conversion is capped by basic thermodynamics, and these devices need enough temperature difference to be useful.

The interesting part is cost. Mori told IEEE Spectrum that estimated costs suggest an industrially competitive power-generation cost could be possible “for the first time in thermoelectric history.”

TEGNet also identified designs that could use simpler fabrication and, in some cases, avoid bismuth telluride, a common but expensive thermoelectric material.

That could help waste-heat harvesters and high-performance home heat pumps become cheaper, although real-world manufacturing still has to prove the numbers.

• Graphene experiment reveals major breakdown of Wiedemann-Franz law
• Heat and electrical conduction unexpectedly move in opposite directions
• Deviation from classical law exceeds two hundredfold under conditions

For decades, the Wiedemann-Franz law stood as a reliable rule in condensed matter physics.

This principle holds that a material’s ability to conduct electricity should rise and fall in lockstep with its ability to conduct heat.

A team of researchers from the Indian Institute of Science and the National Institute for Materials Science in Japan has now documented a dramatic violation of this long-standing tenet.

An Unexpected Reversal at the Dirac Point

Their experiments on graphene, a single layer of carbon atoms, show that electrical conductivity and thermal conductivity can move in opposite directions rather than together.

The scientists created exceptionally clean graphene samples to eliminate interference from atomic defects and impurities.

They then carefully measured both electrical and thermal conduction across a range of conditions. What emerged was a striking contradiction to established physics.

As electrical conductivity increased, thermal conductivity dropped, and the reverse also occurred.

At low temperatures, the observed deviation from the Wiedemann-Franz law exceeded a factor of 200.

This separation between charge flow and heat flow is not a minor anomaly but a fundamental breakdown of a rule that has guided physicists for more than a century.

Despite this apparent lawlessness, the behavior is not random. Both types of conduction appear to obey a universal constant that does not depend on the specific properties of the material.

This constant connects directly to the quantum of conductance, a basic quantity that governs how electrons move at the smallest conceivable scales.

The researchers reached this unusual state by tuning the electron density to a special condition known as the Dirac point, where graphene hovers exactly between being a metal and an insulator.

At this critical point, electrons stop acting as independent particles. Instead, they move collectively, forming a fluid that flows with remarkably low resistance.

"Since this water-like behavior is found near the Dirac point, it is called a Dirac fluid — an exotic state of matter that mimics the quark-gluon plasma, a soup of highly energetic subatomic particles observed in particle accelerators at CERN," explains Aniket Majumdar, first author and PhD student at the Department of Physics.

The team measured the fluid’s viscosity and found it to be extremely low, making this system one of the closest realizations of a perfect fluid ever observed in a laboratory.

This discovery transforms graphene into a tabletop window into extreme physics.

Scientists can now investigate phenomena usually associated with black hole thermodynamics and high-energy particle collisions without leaving their labs.

The Dirac fluid might enable highly sensitive quantum sensors capable of detecting faint magnetic fields or amplifying extremely weak electrical signals.

Although the experiment does not overturn all of physics, it does show that even fundamental laws have limits when quantum mechanics and collective electron behavior collide.

Via Science Daily

• Mycelium might power electronics someday, if it stops biodegrading before the job is done
• The split-gill mushroom’s extracellular matrix may be the key to future green batteries
• Scientists dream of compostable batteries, but controlling fungal behavior remains a major challenge

Researchers from Empa, the Swiss Federal Laboratories for Materials Science and Technology, are exploring the potential of fungal mycelium to create a compact, biodegradable battery.

Their goal is to use mycelium to produce “fungal paper” for battery electrodes - a concept that, according to researcher Ashutosh Sinha, remains in the experimental phase.

“We want to produce a compact, biodegradable battery whose electrodes consist of a living 'fungal paper,’” Sinha states, emphasizing that this vision is still a dream for now.

The dream of biodegradable batteries

The idea of a biodegradable battery made from living materials is ambitious. The team is working with the mycelium of the split-gill mushroom, a fungus known for its unique mechanical and biological properties.

This fungus is naturally biodegradable and, when combined with its extracellular matrix, produces a material with promising potential for sustainable applications in technology.

The aim is to develop a system that decomposes without releasing harmful waste - unlike conventional electronic devices - by using the natural properties of the material.

Empa researchers are now examining how the tensile strength of mycelium and its sensitivity to moisture can be applied in components like biodegradable sensors and batteries.

Working with living materials brings notable challenges. Mycelium’s biodegradable nature is both an advantage and a limitation.

On one hand, it could significantly reduce the environmental impact of batteries. On the other, its tendency to degrade raises concerns about its longevity and reliability in electronic devices.

Living materials also respond to their environments, making it difficult to predict or control their behavior consistently.

“Biodegradable materials always react to their environment. We want to find applications where this interaction is not a hindrance but maybe even an advantage,” said Empa’s Gustav Nyström.

The idea of a compact, biodegradable battery with fungal paper electrodes remains conceptual, and one of the biggest challenges will be refining the material to meet performance standards required in modern electronics.

Nevertheless, it represents a promising step toward more sustainable and environmentally conscious electronics.

You might also like

• Ten years of OSSRA: what a decade of data tells us about the state of open source security
• A third of enterprises have been breached despite increased cybersecurity investment
• GlobalX airline is helping Trump deportations hit by cyberattack

Scientists from the Massachusetts Institute of Technology (MIT) have created a new material using a new polymerizing process. The material, called 2DPA-1, a type of polyaramide, is said to be as light as plastic and as strong as steel; even better, it can be manufactured at industrial scale which bodes well for its go-to-market timeframe.

The material, which is the first polymer to be polymerized in 2D, adopts a planar structure, as opposed to a string one; think spaghetti lines and lasagne sheets. The team, led by Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT, managed to crack a problem that has left many generations of Ppolymer scientists befuddled.

2DPA-1 can sustain deformative forces up to six times greater than bulletproof glass and has a yield strength (the force required to break the material) 12 times that of steel at equal density. Another intriguing property is that it is impermeable to gases which could mean waterproof ultrathin coatings.

What does that mean for consumers and businesses?

It is still early days but 2DPA-1 could mark the beginning of something very special. Rolling the process out (patents have already been filed) could take a few years but its impact on everyday life won’t take too long given that the new polymerization process uses existing technology.

From ultrathin, totally waterproof coatings to super light chassis for laptops and smartphones (in lieu of say magnesium or aluminum alloys), there’s plenty of scope in a variety of industries. It could replace paint to protect metal in certain cases, replace metal in bridges and structures that require high tensile strength and malleability.

It could even become an integral part of data centers as it could help produce waterproof servers that do not need active cooling systems or be used to produce safer vehicles. The next step in the research is to understand how the polymer turns into 2D sheets in the first place and whether other types of materials can be produced (e.g. 3D version).

Other questions remain: how safe is it when burnt? At what temperature does it ignite? Is it food-safe? How does it degrade?

• This new polymer could find its way in a rugged hard drive or a rugged smartphone one day.

Most prototypes of electronic skin that have been developed over the last decade or so are designed to sense only light pressure. The sensor that recognises when the skin is being touched doesn't respond effectively to harder impacts. In some cases they just break.

So engineers at the Huazhong University of Science and Technology have developed a system that could let robots know when they're hit hard enough to potentially cause damage. And it's inspired by jellyfish.

To be specific, the Atolla jellyfish - which lives in the deep ocean and flashes its bioluminescent organs dramatically when it senses danger based on changes in water pressure.

Physical threat

Bin Hu and his team built on that idea of a visual warning of a physical threat to develop a system that lights up when it's damaged. It's made of two layers that allow it to detect slight pressures - like a leaf or a breeze - as normal. 

But between the layers is another that's embedded with phosphorescent materials which glow brighter and brighter as physical force increases. Being able to sense a wider range of pressures, the researchers say, makes the system more like human skin.

"Mimicking the pressure-sensing behavior of biological skins using electronic devices has profound implications for prosthetics and medicine," wrote the researchers in a paper published in ACS Applied Materials and Interfaces.

"Its mechanically robust and stretchable properties may find a wide range of applications in intelligent robots."

• Spider silk could make your smartphone calls clearer

Sound, as I'm sure you're aware, is basically just vibrations in the air. Microphones work by translating those vibrations into electronic signals, and then passing those signals on to something else - usually a computer of some sort.

Different microphones perform that task in different ways, but the electret microphones used in most smartphones and tablets do it by measuring the change in distance between two plates inside a tiny capsule. When a sound wave comes along, the pressure inside the capsule changes and the plates move. It works pretty well.

But a team of researchers at Binghamton University believe there might be a better way. Ron Miles and graduate student Jian Zhou think that we could learn from the way insects listen to build more sensitive microphones.

Hear Hair Hear

"We use our eardrums that pick up the direction of sound based on pressure, but most insects actually hear with their hairs," Miles explains. Those hairs, which are spread across the body, move with the sound waves travelling through the air.

In a study recently published in the journal PNAS, Miles and Zhou lay out a system that uses spider silk to do something similar. “We coated spider silk with gold and put it in a magnetic field to obtain an electronic signal,” said Miles. 

Spider silk is thin enough that sound waves can make them move. “This can even happen with infrasound at frequencies as low as 3 hertz.”

The benefit of this extra fidelity is that it makes it easier to filter out background noise - great for mobile phone microphones, but also great for hearing aid users and more. 

“It’s actually a fairly simple way to make an extremely effective microphone that has better directional capabilities across a wide range of frequencies," said Miles.

• Reprojection could make your VR experiences lag-free

Yesterday we learnt that future space missions could face an unexpected problem - microbes build up inside a spacecraft sealed for months on end.

But with a new day comes a new solution - a novel textile called Surfaceskins that is able to disinfect itself, killing more than 90 percent of the bacteria on the surface.

The material is the creation of a team from the University of Leeds, who've been working on it for about seven years. It works by dispensing a small amount of alcohol gel when it's pushed, disinfecting the surface.

It's built up of three separate non-woven textiles, the researchers say, creating tiny valves that pump out the alcohol gel. It wouldn't be suitable for every surface, as it needs replacing every seven days, but it could be useful for areas that are frequently touched.

Hospitals

The team, who have formed a spin-off company to commercialise the technology, imagines that it could prove particularly useful in hospitals back on Earth. 

Doors in hospitals are touched by many people over the course of a day, and only one person with dirty hands can spread contamination to everyone else. But by covering a portion of the door with this material, it could be kept sterile. The team has also invented a door handle using the same technology.

In tests, the team found that Surfaceskins was more effective than a standard door plate, over a period of seven days, in reducing levels of three bacteria that cause common infections.

Mark Wilcox, a Professor of Medical Microbiology at the University who led the testing, said: "Our results suggest that Surfaceskins door pads can help to reduce the contamination of doors by microbes."

"They offer a new way to reduce the risk of the spread of bacteria and viruses in hospital environments and other settings where frequent contact with doors could undermine hand hygiene."

The details of the tests were published in the Journal of Hospital Infection. 

• Tiny stowaways could jeopardise future space missions

I have some eggcellent news. Materials scientists have found that egg white can be turned into a film-like substance that's perfect for making memory units.

Researchers from Southwest University in China, led by Qunliang Song, showed that when egg white is mixed with hydrogen peroxide, a series of chemical reactions occur that allow the material to be turned into a film that can be used to make transparent, flexible resistive memory.

Here's how it works. Egg white contains more than 40 different proteins, containing iron, sodium and potassium ions, linked together with weak chemical bonds. When you mix it with bleach, the bonds are broken and the ions are exposed. 

Those ions, which are positively charged, can then capture negatively charged electrons that are injected when a voltage level is applied. When there are few electrons around, the material behaves as an insulator, but when there are lots the material becomes conducting. To reset it, you can then apply a positive voltage - releasing the electrons.

Switching endurance

It's not the first time that egg white has been used to make electronics. Transistors and other devices have been fabricated from chicken and duck eggs. But this is the first time it's been used to make memory. In testing, it showed a high on/off resistance ratio, and good retention and switching endurance even after repeated bending.

"As a promising alternative to the conventional silicon-based nonvolatile memory, the egg albumen has more advantages than other materials," Song told Phys.org. 

"The bio-organic material egg albumen may have potential applications in the imitation of biological memory behavior, artificial intelligence, and brain-like intelligence because of the good compatibility."

He added: "We will continue our investigation of the mechanism of resistive switching memory. At the same time, flexible, wearable and water-dissolution resistive switching memory cells will be developed using organic-modified egg albumen in our following work."

The team published the details of their work in the journal Nanotechnology. 

• The US and Russia want to build a Moonbase together

Around the world, there are a large number of labs working on artificial skin technology. The reason is simple - a breakthrough in this field could bring big benefits to many fields, from robotics to medicine.

The latest research group to publish their work is at the University of Houston. A team there, led by Cunjiang Yu, has developed a composite of rubber and semiconductors that can be stretched by up to 50 percent without damaging its electronic components. 

“Our strategy has advantages for simple fabrication, scalable manufacturing, high-density integration, large strain tolerance and low cost,” he said. 

Hot and cold

Normally, semiconductors are brittle and so using them in stretchable materials means creating complicated mechanical systems. This is the first work, the team claims, that embeds semiconductors in a stretchable material without any special mechanical structure.

In testing, the team showed that their skin could allow a robotic hand to sense the temperature of hot and iced water in a cup, and then perform the signals for hot and cold in American Sign Language.

“The robotic skin can translate the gesture to readable letters that a person like me can understand and read,” Yu said.

Beyond Robotic Hands

It's hoped that the system could be used beyond robotic hands too - perhaps in health monitors, medical implants and human-machine interfaces.

"We foresee that this strategy of enabling elastomeric semiconductors by percolating semiconductor nanofibrils into a rubber will advance the development of stretchable semiconductors," the team wrote in a paper published in the journal Science Advances.

"It will move forward the advancement of stretchable electronics for a wide range of applications, such as artificial skins, biomedical implants and surgical gloves."

• Engineers are getting ready to hook up the quantum internet

Touchscreens have come on leaps and bounds since the first smartphones emerged almost twenty years ago. But now biologists are discovering that the rapid progress made in developing the technology could have benefits elsewhere too.

A team from the Karolinska Institute in Stockholm has been experimenting with the conducting plastics used in smartphone screens. They've published a paper showing that by manipulating electrons on the surface of the plastic, bacteria can be tricked into growing more or less.

Here's how it works. When bacteria land somewhere where the conditions are right, they multiply into a thick film known as a "biofilm" that covers the surface. These exist all over the place - including your body - but can pose a danger in places like hospitals where they can cause infections.

The team, led by Agneta Richter-Dahlfors, found however that conducting plastics can encourage or discourage that growth. “When the bacteria land on a surface full of electrons, they cannot replicate”, she said. 

“They have nowhere to deposit their own electrons which they need to do in order to respire.” 

Opposite voltage

The opposite is also true. If the opposite voltage is applied then the bacteria can spread more rapidly. 

“With the electrons being continually sucked out of the surface, bacteria could continually deposit their own electrons, giving them the energy they needed to grow quickly,” said Richter-Dahlfors.

The next step is to test whether this principle can be used to develop cheap coatings for medical instruments that inhibit the spread of pathogens. 

“To begin with, we can coat medical devices with this material to make them more resistant to colonisation by bacteria”, says Professor Richter-Dahlfors. 

“However, if we look to industries like wastewater management that need a lot of beneficial biofilms to create clean water, we can produce surfaces that will promote biofilm production”, she said.

The full details of the technology were published in the journal NPJ Biofilms and Microbiomes. 

• This pen-sized device can identify cancerous cells in seconds

Computer scientists from the University of St Andrews have developed a smartphone app that uses the device's front-facing camera to recognise what kind of surface it's sitting on.

The app is called SpeCam, and links up with an existing database of materials. When it detects a particular surface, it can trigger a specific action. The researchers suggest that you could trigger it to play jazz when placed on the sofa, or dance music if on a coffee table.

Multi-Spectral

Its actions aren't limited to music. If your phone rings and you place it face-down on your laptop, it could send a message reading "sorry, I'm in a meeting", but if you put it in your pocket instead it could send a different message - perhaps suggesting that the caller contacts a colleague.

It works by using the device's screen as a multi-spectral light source, and the front-facing camera to then capture the reflection of the material that it has been placed on. After cycling the screen through different colors, the material can be detected. You can see it in action here:

Discreet Computing

"This is an example of what we call Discreet Computing or discreet interaction, where subtle and inconspicuous user actions can result in entirely new forms of interaction," said Lead researcher Professor Aaron Quigley, Chair of Human Computer Interaction at St Andrews. 

"By training and hence recognising materials all the surfaces around us become a canvas for our imagination." 

Hui Yeo, who contributed to the research, added: "The goal is to explore novel forms of interaction for one-handed use which can leverage what people already do with devices, without adding new hardware to the device."

A paper describing the technology will be presented at the 19th International Conference on Human-Computer Interaction with Mobile Devices and Services, ACM SIGCHI MobileHCI 2017 on 6 September in Vienna, Austria.

• Astronaut Peggy Whitson returns to Earth after a record-breaking stay in space

When life gives you lemons, make lemonade. But what happens when life gives you carbon dioxide emissions? Chemists at George Washington University say: "Make carbon nanotube wool". 

A team of researchers led by Stuart Licht have a vision for turning CO2 emissions from a pollutant into a valuable resource, and perhaps even a substantial business opportunity. In a study just published in Materials Today Energy, they described how CO2 sucked out of the atmosphere can be combined with solar energy to produce large amounts of carbon-nanotube (CNT) wool.

What's that? Glad you asked. It's millimetre-length fibres that can be woven into textiles to make metals, cement replacements and other things. The production process can be done at a cost of $660 per tonne, the researchers say. But the market value of the substance is currently between $100,000 and $400,000 per tonne.

"We have introduced a new class of materials called 'Carbon Nanotube Wool,' which are the first CNTs that can be directly woven into a cloth, as they are of macroscopic length and are cheap to produce," Licht told Phys.org. "The sole reactant to produce the CNT wools is the greenhouse gas carbon dioxide."

Strength-to-mass

The team has been working on the process since about 2010. Previously, they were only able to create very short-length nanotubes - less than 100 micrometres long, which can't be woven. 

They solved that problem by replacing a key component made of copper or steel with one made of Monel - a nickel-copper alloy. With subsequent tuning, they were then able to produce much longer fibres.

"Inexpensive, weavable CNT wools are preferred replacements for conventional steel and aluminum applications, due to the CNT wool's lightweight, strength-to-mass advantage," Licht said. 

"In addition to textiles, CNT wools serve as preferred additives to formulate blast- and fracture-resistant cement and ceramics. Other applications of stronger-than-steel, highly conductive CNT cloth are bullet-proof CNT suits and taser-proof suits."

• Hate traffic noise? Just wait until drone buzz becomes more common

Materials scientists have fabricated printed transistors that consist entirely of 2D nanomaterials for the first time - a breakthrough that could herald the arrival of cheap, flat displays mounted on almost anything. 

"We believe that 2D nanomaterials can compete with the materials currently used for printed electronics," said Jonathan Coleman, from Trinity College in Dublin. "Compared to other materials employed in this field, our 2D nanomaterials have the capability to yield more cost effective and higher performance printed devices."

Two-dimensional nanomaterials are especially suited for this purpose because they have a range of interesting electronic properties but they're also easy to produce in large quantities at a low cost. 

The breakthrough here, though, is in showing that different kinds of nanomaterial - conducting, semiconducting and insulating - can be combined together in complex devices. 

"We believe this work opens the way to print a whole host of devices solely from 2D nanosheets," said Coleman, who led the research.

Substantial scope

In tests, Coleman's team used standard printing techniques to combine nanosheets of graphene with two other nanomaterials - tungsten diselenide and boron nitride - to form a working transistor.

While the performance of their transistor can't yet match traditional transistors, the team claims there's substantial scope for improvement. "In the future, printed devices will be incorporated into even the most mundane objects such as labels, posters and packaging," said Coleman. 

He added: "Printed electronic circuitry (constructed from the devices we have created) will allow consumer products to gather, process, display and transmit information: for example, milk cartons could send messages to your phone warning that the milk is about to go out-of-date."

"We believe this work opens the way to print a whole host of devices solely from 2D nanosheets."

Coleman and his colleagues published details of their work in the journal Science.

• An AI is turning paintings into realistic photos

There's little doubt that wearables will be a major part of the way we interact with technology in the future. But present-day wearables are problematically rigid - to become a bigger part of our lives, they'll need to become more like everyday clothing and less like jewelry for special occasions.

Materials engineers know this, and for years they've been working on ways to make electronics more flexible. 

Now, a team of researchers from North Carolina State University have taken a step closer with the creation of elastic, touch-sensitive fibers that can interface with electronic devices.

“Touch is a common way to interact with electronics using keyboards and touchscreens,” said Michael Dickey, corresponding author of a paper describing the technology, published in the journal Advanced Functional Materials.

How they work

The fibers work by twisting together three strands of tube-like polymers with a liquid metal alloy in their centre - each strand a little wider than a human hair. One is totally filled with the alloy, one two-thirds filled and one only one-third filled.

When a human finger moves along the fiber, it comes into contact with different strands and the capacitance between the finger and the alloy changes, telling a connected system which part of the fiber is being touched. 

You can see it in action here:

Soft Robotics

As well as future wearables, it's hoped that the technology could be used in soft robotics and other applications where elasticity is important, especially as the fibers can integrate with existing textiles and are easy to mass-produce at high speeds.

“We have created soft and stretchable fibers that can detect touch, as well as strain and twisting," said Dickey. 

"These microscopic fibers may be useful for integrating electronics in new places.”

• The Death Star's laser may no longer be science fiction

We've written quite a bit about artificial skin in the last few years. It's a fast-moving field -- a lot of research is going into developing thin electronic systems packed with sensors that are not only flexible but also cheap to manufacture in bulk.

The idea is that such systems could be used to allow robots to experience the world around them in a similar way to humans - passively sensing pressure, temperature and more through their skin. It has applications beyond robotics too - bridges could feel when they're failing, for example, and alert someone.

The latest research comes out of MIT's Computer Science and Artificial Intelligence Laboratory. Researchers there have 3D-printed a device that can respond to mechanical stresses (like being poked) by changing the color of a spot on its surface.

Initial demonstration

It was inspired by the golden tortoise beetle, a species native to the Americas. The beetle's skin normally appears golden, but turns red-orange when poked. 

“In nature, networks of sensors and interconnects are called sensorimotor pathways,” said Subramanian Sundaram, who led the project.

“We were trying to see whether we could replicate sensorimotor pathways inside a 3-D-printed object. So we considered the simplest organism we could find.”

The resulting T-shaped device is made of elastic plastic with a strip of silver mounted on it, and a more rigid section of plastic with two printed transistors and a "pixel" - a semiconducting polymer which changes colour when the silver strip is stretched. It's powered by a regular 1.5V battery.

It was printed on a custom 3D-printer developed by the researchers, using two different print heads (for hot and cool substances) and ultraviolet light-emitting diodes to harden the printed substances. 

Right now, it can operate for about two months, but the researchers say that by replacing some components it could be made more durable. 

"That’s something we would work on later," said Sundaram. "This is an initial demonstration."

The team published their work in the journal Advanced Materials Technologies.

• Germany has switched on an 'artificial sun'

Wireless power transmission has been on the cards ever since Nikola Tesla first demonstrated the technology in the 1890s. But with few exceptions, wireless power has never quite made it to the mass market.

The closest thing we have are the wireless magnetic induction pads that several technology firms launched a few years back, but as your device has to effectively rest on the charging pad it's hard to call it wireless.

Now, however, engineers at Duke University, the University of Washington and Intellectual Ventures' Invention Science Fund have shown that the technology already exists to build a proper wireless charging system - we just need to design it.

Synthetic Metamaterials

After surveying several different options for wireless power, the team settled on a solution that involves synthetic metamaterials comprised of individually engineered electrical cells. 

"As long as you’re within a certain distance, you can build antennas that gather electromagnetic energy and focus it, much like a lens can focus a beam of light,” explained Duke University's David Smith, lead author on a new paper describing the technology. 

According to their results, a flat device no larger than a typical television could focus beams of microwave energy down to a spot the size of a phone at a distance of up to ten metres. It could also power more than one device at the same time. 

"The ability to safely direct focused beams of microwave energy to charge specific devices, while avoiding unwanted exposure to people, pets and other objects, is a game-changer for wireless power," said co-author Matt Reynolds from the University of Washington.

Walking into the Beam

There are still bridges to cross. Getting the system to shut off if a person walks into the beam is important. So is optimisation of the software and controls for the antenna. But Smith is bullish on the possibilities. “All of these issues are possible to overcome—they aren’t roadblocks,” he said. 

“We actually came up with some nice analytical formulas for coverage areas and efficiencies that would be possible. I think building a system like this, which could be embedded in the ceiling and wirelessly charge everything in a room, is a very feasible scheme. Moreover, there are versions of the concept that can deliver larger power over much larger distances”

The full details of the research were published on the arXiv pre-print server.

• Your next smartphone will get a bug's-eye view of the world

Antlers are pretty remarkable things. Most species of deer grow and shed them every year, and the rate at which they increase in size makes them the fastest-growing bone among mammals.

The other thing that's pretty remarkable about antlers is how resilient they are. Evolved for fighting, they absorb huge amounts of energy during male-on-male combat without breaking. Now, materials engineers are studying them to find out how.

Researchers at the Queen Mary University of London used x-ray scans and computer modelling to probe the nanostructure of deer antlers. They found a unique arrangement of fibres, which they say makes the substance more resilient.

"The fibrils that make up the antler are staggered rather than in line with each other," said Paolino De Falco, the first author on a paper describing the work. "This allows them to absorb the energy from the impact of a clash during a fight."

Filling in Gaps

As well as opening up possibilities for the creation of similarly damage-resistant materials, the discovery fills in gaps in the structural modelling of bone.

"Our next step is to create a 3D printed model with fibres arranged in staggered configuration and linked by an elastic interface," said Ettore Barbieri, who also contributed to the research.

"The aim is to prove that additive manufacturing -- where a prototype can be created a layer at a time -- can be used to create damage resistant composite material."

The full details of the research were published in the journal ACS Biomaterials.

• The world's smallest radio receiver has parts that are two atoms in size

Let me tell you a little bit about your intestines. You probably recall from school that there are two parts - a small and a large intestine. The large bit is basically poop storage. The small bit is more interesting - it's where most of the digestion and absorption of food takes place.

Key to that absorption process are the 'villi' that line the walls of the intestine. These finger-like protrusions, each about a millimetre long, massively increase the surface area of the intestine, making digestion way more efficient.

Now, a team of Chinese and British materials scientists have used exactly the same principle to make batteries way more efficient. They've developed a next-generation lithium-sulphur battery that has tiny nanoscale fingers coating its electrodes. As well as increasing the surface area, they also trap fragments of the electrode that break off, keeping them electrochemically accessible.

Through the bottleneck

"It's a tiny thing, this layer, but it's important," said study co-author Paul Coxon from Cambridge's Department of Materials Science and Metallurgy. "This gets us a long way through the bottleneck which is preventing the development of better batteries."

Teng Zhao, a PhD student from the Department of Materials Science & Metallurgy at the Beijing Institute of Technology, added: "By taking our inspiration from the natural world, we were able to come up with a solution that we hope will accelerate the development of next-generation batteries."

So far this is just a proof of principle, so it'll be a while until lithium-sulphur batteries become commercially available. There are other issues to solve before that happens too - lithium-sulphur batteries still don't last as long as lithium-ion batteries.

"This is a way of getting around one of those awkward little problems that affects all of us," said Coxon. 

"We're all tied in to our electronic devices - ultimately, we're just trying to make those devices work better, hopefully making our lives a little bit nicer."

The full details of the research were published in Advanced Functional Materials.

• This robot tutor detects the 'emotional state' of its pupils

Apple made a big deal out of its newly-waterproof iPhone 7 in an event broadcast around the world this week. But it could already be out of date, as Australian engineers have just announced the discovery of a new spray-on material that has remarkable water-repellant qualities.

While there are a bunch of super-hydrophobic coatings on the market, they tend not to last for very long. This reason is that the nanostructures that allow them to repel water break up and degrade over time.

Fishing Nets

But the new coating, developed by a team led by William Wong at the Australian National University's Research School of Engineering, combines two plastics, one flexible and one tough, making it substantially more robust.

"It's like two interwoven fishing nets, made of different materials," Wong said. There are two ways to make it, both cheaper and easier than current manufacturing processes. The coating is also transparent and highly resistant to ultraviolet radiation.

"We can apply it to practically everything," Wong added. "So you could have paper, cardboard, wood, clay, stone, bricks, plastics, windows, building materials of any sort. Anything you can practically think of."

Real-World Applications

That means your next phone could be substantially more waterproof than models currently on the market. But the potential applications don't stop there.

"The key innovation is that this transparent coating is able to stabilise very fragile nanomaterials resulting in ultra-durable nanotextures with numerous real-world applications," said Antonio Tricoli, who also worked on the project.

"It will keep skyscraper windows clean and prevent the mirror in the bathroom from fogging up." It could also prevent ice from forming on the bodies of aeroplanes, or protect boats from corrosion.

The same principles used to make this material could even help develop a wide range of other coatings. "A lot of the functional coatings today are very weak, but we will be able to apply the same principles to make robust coatings that are, for example, anti-corrosive, self-cleaning or oil-repellent," said Wong.

The team's research was detailed in a research paper published in ACS Applied Materials & Interfaces, and summarised in the following video:

• This year's James Dyson Award UK winner could well be a life-saver

• Duncan Geere is TechRadar's science writer. Every day he finds the most interesting science news and explains why you should care. You can read more of his stories here, and you can find him on Twitter under the handle @duncangeere.

For decades, we've been promised 'smart windows' – glass which can lighten or darken based on the conditions outside, saving on cooling and heating bills for homes and businesses.

But, while they've featured in a few concept buildings, smart windows haven't made it into the mainstream. The reason isn't technology – the science is pretty settled. It's more about the cost and difficulty of manufacturing them, which makes them prohibitively expensive.

Unique nanostructure

But now a team of researchers from the Cockrell School of Engineering at the University of Texas might have a solution. They've figured out how to make a smart window coating that's far easier and cheaper to apply than traditional methods.

It involves creating a plastic film with a unique nanostructure that doubles the efficiency of the darkening process. It can be made at low temperatures, and can switch between clear and tinted modes more quickly, using less power, than the traditional high-temperature process.

In testing, the team created a flexible coating that can be lightened or darkened with a small electric charge – about four volts. By applying that coating to glass, the transmission of heat through the glass can be controlled.

Rapid and efficient

What's more, the team reckons the discovery could pave the way for the deliberate engineering of similar materials for other applications – supercapacitors that store and release electrical energy rapidly and efficiently, for example.

Graeme Henkelman, a co-author on the paper describing the discovery, said: "Such collaborative efforts that combine complementary techniques are, in my view, the key to the rational design of new materials."

• Jellyfish skin could stop glare on your screens

• Duncan Geere is TechRadar's science writer. Every day he finds the most interesting science news and explains why you should care. You can read more of his stories here, and you can find him on Twitter under the handle @duncangeere.

When you submerge your hand in water for a while, your fingers begin to wrinkle. Why? It's not an entirely settled question, but the current thinking is that it gives humans a better grip on wet objects.

Jellyfish skin also wrinkles, but not in the presence of water (or they'd be wrinkled their entire lives). "When they're scared, some types of jellyfish form a wrinkled surface that is opaque and warns off predators," says Songshan Zeng, who's working on developing new, wrinkled materials inspired by nature. "That same surface is transparent when it's flat."

New properties

It's hoped these new materials could come with totally new properties. "Our experimental materials use cracks, folds or wrinkles to mimic the surface engineering of skin," says Luyi Sun, heading the research.

"These new materials are unique because they change color or transparency when they're stretched or exposed to moisture."

In tests, the team simulated skin wrinkles by placing a rigid thin film of polyvinyl alcohol on a rubbery base. "Like finger skin, whenever part of the film is exposed to moisture, it swells slightly, generating wrinkles," Sun says. The wrinkled part can be used to form patterns that only appear when the film is moistened.

Anti-glare

The wrinkles can also help improve the anti-glare properties of screens. Wrinkles scatter light in all directions, rather than reflecting them back at the viewer, making a coating with micro-wrinkles a cheap and effective anti-glare treatment for screens.

As well as the wrinkles, the team is also experimenting with the pigments found in squid skin, allowing a material to change topography and appearance reversibly when stretched.

Zeng and Sun are presenting their research this week at the 252nd National Meeting & Exposition of the American Chemical Society.

• This tiny robotic caterpillar will never become a butterfly

• Duncan Geere is TechRadar's science writer. Every day he finds the most interesting science news and explains why you should care. You can read more of his stories here, and you can find him on Twitter under the handle @duncangeere.

Batteries are an essential part of modern life. Your car, mobile phone, laptop, and camera wouldn't exist without them. And researchers around the world are constantly working to make them better.

That includes a team at the HZB Institute for Soft Matter and Functional Materials, which is part of the Institut Laue-Langevin in Grenoble, France. They've been looking at the materials we use to make batteries and trying to figure out if there are better alternatives.

More specifically, they've been looking at the graphite electrodes that form part of the lithium-ion batteries that power most of our household gadgets. Graphite is used because it's cheap, plentiful and stable. However, it can only absorb a limited number of ions before hitting capacity.

More Ions

Silicon is one alternative. It's also pretty plentiful on Earth, and it can absorb way more ions than graphite can. But there's a problem - as the ions migrate through the silicon, it disrupts the crystal structure. That leads to the electrode swelling in volume by a factor of three, which is tricky to deal with.

But the HZB team, led by Matthias Ballauff, believes it has a solution. After tracking exactly where the ions absorb in a silicon electrode, they found that majority stick around in a layer about 20 nanometres thick on the surface of the silicon. Only one in 26 penetrate further.

"We were able to precisely track where the lithium ions adsorb in the silicon electrode using neutron reflectometry methods, and also how fast they were moving", said Beatrix-Kamelia Seidlhofer, who carried out the experiments.

Theoretical Capacity

That suggests that, by using very thin silicon films, it should be possible to develop batteries with a theoretical capacity six times greater than a lithium-ion battery constructed with graphite electrodes. The significantly thinner electrodes would mean that the volume swelling is easier to handle.

That not only saves on material and energy consumed during manufacture, but we get a better battery out as a result.

The research was detailed in a paper in the journal ACS Nano.

• Quantum computers just took a huge logical leap forward

• Duncan Geere is TechRadar's science writer. Every day he finds the most interesting science news and explains why you should care. You can read more of his stories here, and you can find him on Twitter under the handle @duncangeere.

Creating hair, fur, bristles and brushes on a 3D printer is a real pain. It's not a hardware issue; most 3D printers can cope with filaments of plastic just fine. Instead it's a software problem - you have to design and place each hair individually in a CAD program, which takes hours.

Now, however, software engineers at MIT's Media Lab have a solution - they've created a method to quickly and efficiently model and print thousands of hair-like structures on a curved or flat surface of an object.

The software platform that they built to run it, which is called Cilllia, allows users to define the angle, thickness, density and height of thousands of hairs in just a few minutes. It can cope with coarse bristles, fine fur, and even structures as thin as real human hair.

That could mean 3D-printed wigs and hair extensions on shelves soon, but the main goal of the project is actually to see if 3D-printed hair could perform other tasks. In the natural world, hair-like structures perform many diverse tasks from sensing, to adhesion, to moving objects around.

Tunable and Controllable

So far, they've managed to create arrays of hairs the can stick to each other like velcro, that can detect when a person strokes a surface in certain directions, and that can even sort coins by weight.

"It's very inspiring to see how these structures occur in nature and how they can achieve different functions," said Jifei Ou, lead author of a paper describing the project.

"We're just trying to think how can we fully utilize the potential of 3D printing, and create new functional materials whose properties are easily tunable and controllable."

"With our method, everything becomes smooth and fast," he added. "Previously it was virtually impossible, because who's going to take a whole day to render a whole furry rabbit, and then take another day to make it printable?"

• These people are building an electronic nose. How does it smell?

• Duncan Geere is TechRadar's science writer. Every day he finds the most interesting science news and explains why you should care. You can read more of his stories here, and you can find him on Twitter under the handle @duncangeere.

Bad news for sci-fi enthusiasts. Chinese nanotechnologists have calculated that the carbon nanotubes are nowhere near strong enough to build a space elevator out of.

In case you're unfamiliar with carbon nanotubes, they're a "wonder material" made up of carbon atoms arranged into hexagons that make up a tube.

They have weird and exciting electronic, magnetic and mechanical properties - including a tensile strength 100 times greater than steel with only one-sixth the weight.

• 5,000 robots are preparing to explore the Universe

That has lead some to suggest they could be woven into a fibre that would be strong enough to stretch into space, creating a 'space elevator' that could quickly and cheaply ferry goods and people into orbit.

Unfortunately, the carbon nanotube fibres that we've made so far are about a hundredth as strong as they should be. To find out why, Feng Ding from Hong Kong Polytechnic University lead a team that simulated what's happening at the nanoscale.

Weak Points

They built a model of a carbon nanotube with just one atom out of place - turning two of the hexagons into a pentagon and a heptagon. In tests, this tiny fault acted as a weak point, snapping much more easily than the adjacent hexagons.

Once it broke, the resulting strain on the rest of the structure was enough to totally unravel it.

With just one fault of this kind, the theoretical maximum tensile strength of a nanotube was cut from 100 gigapascals to just 40, with the effect even more severe when more faults were introduced. It's thought that a tensile strength of 50 gigapascals would be the minimum required for a functioning space elevator.

"Only carbon nanotubes with extreme quality are able to retain their ideal strength," Ding told New Scientist. "Most mass-produced carbon nanotubes are highly defective, and high-quality carbon nanotubes are hard to produce in large quantity."

Ding added: "Unless great breakthroughs on carbon nanotube synthesis can be achieved, using carbon nanotubes to build a space elevator would be extremely challenging."

He's right. A working space elevator would require 22 miles of carbon nanotube fibre without a single atom in the wrong place.

In space, where radiation and solar winds become a factor, that's pretty much an impossibility. Ah well - for the time being it looks like we'll have to stick with SpaceX's reusable rockets for getting things into space instead.

• Duncan Geere is TechRadar's science writer. Every day he finds the most interesting science news and explains why you should care. You can read more of his stories here, and you can find him on Twitter under the handle @duncangeere.

Image credit: Liftport // CC BY 3.0

Researchers at Cornell University have developed a hybrid material that combines stiff metal with soft rubber foam, and can shift between the properties of both.

To make it, an alloy of bismuth, indium, and tin (called Field's metal) is mixed with a porous silicone foam. The foam is dipped in the molten alloy and then placed into a vacuum so that the air in its pores is removed and replaced by the metal.

The alloy has a low melting point of just 62C, and when heated above this level it'll melt - making the whole substance soft and pliable. When it cools, it regains its rigidity in whatever shape it was bent to. Once re-heated, it again softens and regains its original shape.

'A skeleton when you need it'

"It's sort of like us – we have a skeleton, plus soft muscles and skin," said Rob Shepherd, who lead the research team that developed the substance. "That's what this idea is about, to have a skeleton when you need it, melt it away when you don't, and then reform it."

The material was specifically designed to be biocompatible, containing no toxic substances like lead that are often found in other alloys.

"Sometimes you want a robot, or any machine, to be stiff," said Shepherd, whose group is also working on electroluminescent skin. "But when you make them stiff, they can't morph their shape very well. And to give a soft robot both capabilities, to be able to morph their structure but also to be stiff and bear load, that's what this material does."

Shape-shifting

As well as soft robots, the discovery could also pave the way for all kinds of other shape-shifting devices, like an aircraft that could alter wing shape mid-flight to adjust for air conditions. You can see it shift from one shape to another in the video below:

The details of the substance were published in the journal Advanced Materials.

• How computers are helping us fight the Zika virus

From the cutting edge of scientific research we bring you 'tunable' glass, built from nanowires, that can turn from clear to cloudy in an instant. Essentially, it's like having a privacy mode built right into your windows - and it could mean you never need to hang blinds again.

We have the researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences to thank for this one. Although tunable glass has been around for a while, this is the first time scientists have managed to produce something that's cheap and quick enough to be a viable commercial proposition (which of course makes all the difference).

It works by sandwiching glass or plastic between soft elastomers, elastomers that are coated with silver nanowires. These nanowires can then be forced to squeeze together when an electric current is applied - this gives you a randomised coating that effectively frosts the glass.

High voltage

Samuel Shian, one of the researchers who's come up with the new material, says it works like a frozen pond: "If the frozen pond is smooth, you can see through the ice. But if the ice is heavily scratched, you can't see through."

Vary the voltage and you vary the level of translucency, so you can dial it up or down as required depending on who's walking past on the street. Right now though the voltage is too high to be practical inside a home, so the next step for the research team is working on ways to bring this down.

If the technology can be perfected, it could even be sprayed on to large windows used in industrial projects. Shian and his colleagues are now looking to work with partners in the glass manufacturing industry, though you're going to have to stick to your curtains and blinds for the time being.

• Researchers fool phone fingerprint tech with an inkjet printer

Via Engadget

Overheating is a common problem during exercise, but Finnish researchers are working on a smart fabric that could let your clothes automatically turn on a water cooling system when you get hot.

It works by embedding 'microchannels' into the fabric, which cold (or hot) liquids can flow through. It's similar to the technology that keeps astronauts cool in their spacesuits, but on a much smaller scale.

Scaled to fit

While microchannels have been embedded into fabric before, the process has been limited by high production costs and the small size of the network of channels. Now, however, a team at the VTT Technical Research Centre of Finland has come up with a way of fabricating these microchannels at scale.

As well as cooling and heating in clothes, the technology could be used in rigid plastic to dispense perfume, medicine, or even strong spices at restaurants, in precise quantities.

VTT says it's hoping to commercialise the technology, and is looking for partners in the sports, outdoor recreation, wearable technology and cosmetics industries to help.

• Researchers have warned of the dangers of an augmented reality future

Image credit: Skeeze // CC0

Researchers at Carnegie Mellon University have come up with a technique to create thin, hair-like strands of plastic on a 3D printer.

The way it's done is similar to, and inspired by, the way that glue guns produce thin strands of plastic. "You just squirt a little bit of material and pull away," said Gierad Laput, a PhD student in Carnegie Mellon's Human-Computer Interaction Institute (HCII). "It's a very simple idea, really."

The difficulty is that 3D printer heads aren't designed to be rapidly pulled away. So Laput and his colleagues built a system where the print head and the bed that holds the object being printed can be moved rapidly sideways, allowing them to create the hairs they were looking for.

Cut, Curled or Braided

The resulting process isn't fast, however - it takes about 20-25 minutes to put hair on 10 square millimetres. But it can be done without special hardware, and the resulting hair can be cut, curled or even braided. Dense-close-cropped strands can even form a brush.

So far the team has added hair in various different colours to a number of 3D-printed objects. They've put hair on a troll head, whiskers on an elderly wizard and a tail on a horse. Next, Laput and his colleagues plan to use more sophisticated materials to produce hair with magnetic or other properties.

• Therapeutic robots are helping autistic kids connect with others

You've got a dirty mouth. Streptococci, lactobacilli, satphylococci and corynebacteria all find themselves at home in your gob. But fear not, because dental researchers are working on 3D-printed false teeth that can clean things up in there once and for all.

Andreas Herrmann of the University of Groningen and his colleagues have developed an antimicrobial plastic. "The material can kill bacteria on contact, but on the other hand it's not harmful to human cells," Herrmann told New Scientist.

It works by combining antimicrobial ammonium salts with traditional dental resin polymers. The salts are positively charged, and so disrupt the negatively charged bacterial membranes - causing them to burst. Once mixed, it can be put into a 3D printer and used to create replacement teeth, orthodontic braces and more.

More Experiments

In tests, when coated in saliva and streptococcus mutans (a bacteria that causes tooth decay), it killed more than 99% of the bacteria, compared to just 1% in a control sample without the ammonia salts.

However, the tests were only performed over the course of about six days, so more experiments need to be done to ascertain how safe it is over the longer term - especially when used in conjunction with toothpaste.

Herrmann and his team described their invention in an article in Advanced Functional Materials.

• Spiders are teaching us how to make better glue

A team of researchers at the University of Texas, led by John Goodenough - the inventor of the lithium-ion battery, has developed a crucial component that could pave the way for cheap, safe sodium-ion rechargeable batteries.

Batteries have three main components - an 'anode', a 'cathode' and the 'electrolyte'. Chemical reactions in the electrolyte cause a build-up of electrons at the negatively-charged anode, which then flow through a circuit back to the positively-charged cathode.

Goodenough and his team have been working for several years on sodium-ion batteries, which offer a promising alternative to the lithium-ion cells used in smartphones, laptops and electric cars around the world. Sodium is much more common than the far rarer lithium, making it much cheaper.

Cheap and cheerful

To date, sodium-ion batteries have suffered poor performance, weight and safety compared to their lithium-ion cousins, but now Goodenough believes he's found a cathode material that could change all that. It's made of a non-toxic and inexpensive mineral called eldfellite.

"At the core of this discovery is a basic structure for the material that we hope will encourage researchers to come up with better materials for the further development of sodium-ion batteries," said Preetam Singh, a postdoctoral fellow and researcher in Goodenough's lab. ''We believe our cathode material provides a good baseline structure for the development of new materials that could eventually make the sodium-ion battery a commercial reality."

Details of the discovery were published in the journal Energy and Environmental Science.

• Richard Branson shares his vision of a sustainable world

It seems like every few months scientists announce a new breakthrough on invisibility cloaks. And yet I still get caught when I try to steal pizzas from my local Dominos. What gives?

The latest attempt comes from materials engineers at the US Department of Energy's Lawrence Berkeley National Laboratory, who have managed to build an ultra-thin invisibility cloak that can conceal microscopic objects from detection with visible light.

The difference between this cloak and previous attempts is that it can disguise objects of any shape, and it works in air. "This is the first time a 3D object of arbitrary shape has been cloaked from visible light," said Xiang Zhang, who worked on the device.

"Our ultra-thin cloak now looks like a coat. It is easy to design and implement, and is potentially scalable for hiding macroscopic objects."

On and Off

Like other invisibility cloaks, it works by curving light around the edges of the cloak using metamaterials. In tests, an object the size of a few biological cells was successfully concealed - red light reflected back off the cloak was identical to light reflected off a flat mirror. The effect can be switched on and off at will.

As well as pizza theft, potential real-world applications include superfast optical computers, high-resolution microscopes and even security encryption.

It could even prove useful for 3D displays. For further details, check out the paper that the team wrote for the journal Science.

• How to make anything completely invisible

Image credit: Xiang Zhang group, Berkeley Lab/UC Berkeley

The hexagonal plates of the boxfish's carapace have been identified by engineers as a potential source of inspiration for body armour, robots and flexible electronics.

The characteristically boxy fish has a shell made up of interlocking hexagonal scales, complete with a raised star-like structure in the centre that distributes stress across the surface. After dissecting the scales, researchers discovered a flexible inner layer of interlocking collagen fibres that are tough to penetrate.

"The boxfish is small and yet it survives in the ocean where it is surrounded by bigger, aggressive fish, at a depth of 50 to 100 meters," said Wen Yang, the lead author of the paper describing the discovery. "After I touched it, I realized why it can survive – it is so strong but at the same time so flexible."

35 million years of armour

The connections between the plates offer similar advantages – on impact, the zig-zag patterns lock together and keep the carapace from breaking apart. That's notably different to armour seen elsewhere in nature, which tends to rely on overlapping scales for protection.

"We are currently investigating what mechanical advantage [this structure] might provide," said Steven Naleway, a co-author on the paper. "We know that the boxfish has survived for 35 million years with this armour, so the design has proved very successful in nature."

Image credit: Duncan Geere // CC BY-SA 3.0

• World's most powerful laser fired in Japan

Researchers at Chalmers University of Technology in Sweden have developed a cooling system that takes advantage of graphene's effect on silicon-based electronics. It should lead to a considerable reduction in energy usage.

Getting rid of excess heat is a constant problem for consumer electronics manufacturers - according to a US study, half of the energy required to run computer servers is used for cooling purposes.

A few years back the Chalmers team, led by Johan Liu, successfully showed that graphene has a cooling effect on silicon electronics. But they had trouble getting it working, as the graphene wouldn't stick to the silicon surface.

The name's Bond. Silane Bond.

The solution came in the addition of an extra molecule which could bond properly. "We have now solved this problem by managing to create strong covalent [silane] bonds between the graphene film and the surface, which is an electronic component made of silicon," Liu said.

After testing the bonded graphene, they found it was able to achieve thermal conductivity levels of 1600 W/mK. That's four times the thermal conductivity of copper, the most commonly used heat-sink material.

"Graphene-based film could pave the way for faster, smaller, more energy efficient, sustainable high power electronics," said Liu. Details of the breakthrough were published in the journal Advanced Functional Materials.

• A real shape-shifting transformer is being built for space

MIT's materials scientists have come up with a method for 3D-printing soft materials which go from smooth to bumpy when you squeeze them, forming ridges, bumps or even complex patterns that could guide fluids.

The material consists of two polymers that have differing stiffness levels. More rigid particles are buried below the surface of a softer material, and the spacing of the harder particles determines the patterns formed on the surface when squeezed.

"Depending on the arrangement of the particles, using the same amount of compression, you can get different surface topographies, including ridges and bumps, along the surface," said Mark Guttag, who's working on the research for his doctoral thesis. "There are no previous techniques that provide comparable flexibility for creating dynamically and locally tunable and reversible surface changes."

Bump 'n' Grind

This version of the materials uses squeezing to activate, but there's no reason why the same principles couldn't apply to other stimuli - electric charge, temperature or humidity. Elongated particles under the surface could even allow for asymmetrical surface textures - creating high friction in one direction but not in another.

The applications are widespread - surfaces like this could be useful in adaptive camouflage, limiting the buildup of organisms on the hulls of ships, or controlling motion and turbulence in pipelines. "It could be scaled to all different sizes, and the same principles should work," said Guttag.

Details of the discovery were published in the journal Advanced Functional Materials.

• Drones are noisy, so Nasa is going to shut them up

Strong, lightweight materials are the holy grail for materials scientists, but the bar has just been raised with the discovery of a metal matrix composite so light that it can float on water.

It's made of a foam of magnesium alloy reinforced with silicon carbide hollow particles. That gives its a density of 0.92 grams per cubic centimetre, compared to 1.0 for water, allowing it to bob to the surface when submerged.

That light weight wouldn't be much good, however, if it wasn't also strong - the marine environment is not a gentle one. Impressively, the interior bubbles can withstand a pressure of more than 25,000 PSI before they break - about a hundred times the pressure of a firehose.

Not only that, but the bubbles act as an energy absorber for the material, offering direct impact protection. It can be customised by adding more or fewer bubbles to increase or decrease the density and other properties.

"This new development of very light metal matrix composites can swing the pendulum back in favor of metallic materials," said Nikhil Gupta, the study's co-author. "The ability of metals to withstand higher temperatures can be a huge advantage for these composites in engine and exhaust components, quite apart from structural parts."

The material could be put into prototypes for testing within three years, and its details were published in the International Journal of Impact Engineering.

Up until recently, graphene was heralded as the wonderstuff to end all wonderstuff, but there's a new super-material in town, and its name is nanocellulose. From bendable batteries and flexible screens to superhero-like body armour, nanocellulose could revolutionise our lives.

What is nanocellulose?

Nanocellulose is a nanoscale configuration of good old cellulose, which is one of the most abundant materials on the planet. It's the main constituent of plant cell walls, providing structural support to pretty much every green thing on Earth.

From tree bark to flower stems, it's the material that combined with water produces the effect known as turgor, providing their rigidity and supporting plants like the bones of mammals.

Cellulose itself is simply a combination of glucose molecules, linked in long chains in a particular configuration, differentiating it from starch and other glucose-derived substances.

In its natural state, within plants and other living things, it's useful for materials like paper. As a foodstuff we call it fibre, which you can't digest without help, although cows, sheep and horses can, which is why they graze on grass.

However, when you shrink the structure of cellulose down to the nanoscale and apply a particular configuration to it, things start to get interesting.

You see, a bit like other crystalline constructions, such as incredibly hard diamonds made from a pure carbon crystalline lattice, the structure lends drastically different properties to otherwise unremarkable materials. By forming cellulose into long polymers or meshing it into a crystalline lattice, nanocellulose (or nanocrystalline cellulose, to give it its full name) becomes one of the strongest materials known to man.

It can also conduct electricity and is extremely light, which are properties that make it a super-material with immense potential to change our world.

How nanocellulose is made

The beauty of nanocellulose, before we get on to what we can do with it, is how we can produce it. Up until recently, nanocellulose was produced by treating wood pulp; an expensive and costly process in large quantities. Now a new technique that relies on algae can produce nanocellulose simply from sunlight and carbon dioxide.

The genetically modified blue-green algae produce nanocellulose as part of its energy metabolism, which helpfully also takes in carbon dioxide during the photosynthetic stage. So, not only is producing nanocellulose incredibly cheap and energy efficient, powered only by the sun, but it can also take carbon dioxide out of the air.

Uses for nanocellulose

Now that we're finally on the verge of being able to produce nanocellulose efficiently, cost-effectively, and in useful quantities, it's time to start thinking about what we can actually do with something so strong and light.

Super-flexible displays

The idea of using a flexible display in phones and other portable devices has been banded around for ages now. Unfortunately, one of the leaders in the field, Samsung Display, has hit a few snags of late, which means we've still got a little way to go before we see devices we can actually buy.

Because nanocellulose is both light and strong, and most importantly, transparent, it could make the ideal material to replace glass or plastic in display screens. The nanocellulose could be made into a flexible but strong and durable coating for the bendable displays, enabling all sorts of fancy formats and screens.

That's why Pioneer Electronics is actually looking into it as we speak, crafting some of the thinnest and most flexible displays ever made. It's biodegradable too, which means once you've upgraded your flexible phone, at least one part of it can be recycled.

Bendable batteries

It's all very well having bendable screens, but the other components of our phones, tablets and laptops aren't flexible in the slightest. Nanocellulose could help here too.

Buried within any battery are separators that govern the flow of the cell's electrolyte and electrons. These separators play a crucial structural and functional role within the batteries, meaning we can't simply remove them. However, they are also rigid and inflexible in their current form.

When combined with graphite, nanocellulose conducts electricity while maintaining its strength and flexibility. That means you could, in theory at least, use nanocellulose to create flexible separators, removing one hurdle towards a truly bendable battery.

Of course, you still need a flexible shell around the outside of the cell, but one of our other super-materials can manage that - we wouldn't want graphene to feel left out of the electronics revolution, now would we?

Incredibly strong and light body armour

When you think of body armour, Kevlar probably comes to mind. It's the material most armour not made of plate-steel is constructed with, because the Kevlar fibres knit into a very dense, strong mesh.

Since nanocellulose can be made from incredibly fine fibres too, meshed into a dense crystal lattice in a similar way to Kevlar, it can have a strength-to-weight ratio of up to eight times that of steel.

That makes it the ideal material to construct super-light but incredibly tough body armour, which has the potential to be flexible but still offer good protection.

If you wanted a full-body bullet-proof suit to turn you into a superhero, nanocellulose is what you'd use to make it. In fact, Iron Man could actually be renamed Nanocellulose Man in a couple of years, although it doesn't have quite the same ring to it.

Lighter, faster and more efficient cars

The lighter your car is, the better it will perform. Carbon fibre is the material of choice for high performance cars, but nanocellulose could be the substance to transform our regular cars.

Because nanocellulose is light and strong like carbon fibre, but also cheap to produce with the new algae-based manufacturing methods, it could hold the key to lighter family cars. That'll mean better fuel efficiency and better performing cars, which is both good for the environment and your wallet. In fact, Ford is reportedly already looking into it, meaning your next Fiesta might be even lighter and therefore faster off the mark.

Super-filters and incredible aerogels

As the world gets more and more polluted, finding good ways to filter out the rubbish from our water supply is increasingly important. Nanocellulose can help here too, since its nanoscale crystal lattice can be used to create incredibly fine filters, cheaply.

They can then be used for all sorts of things, from purifying water and blood, or even as chemical filters for things like cigarettes. Nanocellulose could even be used in a desalination technique to rapidly and cheaply produce drinking water from salt water.

If that wasn't enough, because of its strength, nanocellulose can be made into aerogels, or foam, capable of supporting over 10,000 times its own weight, while being incredibly absorbent. It could then be used as super sponges, for anything from wound dressings to water and liquid fuel transport mechanisms. It could even be used to rapidly soak up chemical spills for safe disposal in emergencies.

The beauty of nanocellulose is that, with all these incredible properties, it should be cheap to produce, maintain its strength and structure when wet, and be biodegradable when we're finished with it, making it kind to the planet too.

With so much amazing potential, which we've only scratched the surface of today, that really does make nanocellulose a true super-material.