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Researchers demonstrate hydrogen atoms on graphene yield a magnetic moment

Researchers demonstrate hydrogen atoms on graphene yield a magnetic moment | Amazing Science | Scoop.it

A team of researchers with members from institutions in Spain, France and Egypt has demonstrated that hydrogen atoms on graphene yield a magnetic moment and furthermore, that such moments can order ferromagnetically over relatively large distances. In their paper published in the journal Science the group describes experiments they carried out in attempting to cause a sheet of graphene to become magnetic, how they found evidence that it was possible using hydrogen atoms, and the ways such a material might be used in industrial applications. Shawna Hollen with the University of New Hampshire, and Jay Gupta with Ohio State University, offer some insights into the work done by the team in the same journal issue with a Perspectives piece—they also outline the hurdles that still need to be overcome before magnetic graphene might be used in real applications.

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New world record for fullerene-free polymer solar cells

New world record for fullerene-free polymer solar cells | Amazing Science | Scoop.it
Polymer solar cells can be even cheaper and more reliable thanks to a breakthrough by scientists at Linköping University and the Chinese Academy of Sciences. This work is about avoiding costly and unstable fullerenes.

 

Polymer solar cells have in recent years emerged as a low cost alternative to silicon solar cells. In order to obtain high efficiency, fullerenes are usually required in polymer solar cells to separate charge carriers. However, fullerenes are unstable under illumination, and form large crystals at high temperatures.

 

Now, a team of chemists led by Professor Jianhui Hou at the CAS set a new world record for fullerene-free polymer solar cells by developing a unique combination of a polymer called PBDB-T and a small molecule called ITIC. With this combination, the sun's energy is converted with an efficiency of 11%, a value that strikes most solar cells with fullerenes, and all without fullerenes.

 

Feng Gao, together with his colleagues Olle Inganäs and Deping Qian at Linköping University, have characterized the loss spectroscopy of photovoltage (Voc), a key figure for solar cells, and proposed approaches to further improving the device performance. The two research groups are now presenting their results in the high-profile journal Advanced Materials.

 

We have demonstrated that it is possible to achieve a high efficiency without using fullerene, and that such solar cells are also highly stable to heat. Because solar cells are working under constant solar radiation, good thermal stability is very important, said Feng Gao, a physicist at the Department of Physics, Chemistry and Biology, Linköping University.

 

The combination of high efficiency and good thermal stability suggest that polymer solar cells, which can be easily manufactured using low-cost roll-to-roll printing technology, now come a step closer to commercialization, said Feng Gao.

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Adding a topological fold to origami metamaterials

Adding a topological fold to origami metamaterials | Amazing Science | Scoop.it
Topological mechanics could play a key role in developing "smart" materials of the future

 

A metamaterial that is soft along one edge and rigid along the other, yet also displays mechanical topological properties, has been developed by an international team of researchers. This is the first time that topological origami and kirigami techniques have been applied experimentally to metamaterials – artificial materials with tunable, well-defined properties. Apart from having developed a metamaterial with two distinct topological phases, the team is also working on theoretical guidelines for the future design and development of such materials.

 

Researchers have become increasingly interested in recent years in using he ancient Japanese arts of paper folding and cutting – origami and kirigami, respectively – to build and create a variety of metamaterials. Indeed, Bryan Gin-ge Chen, at the University of Massachusetts Amherst, who led the latest work, sees origami as one of the earliest examples of a metamaterial. "All designs are folded from a square sheet of paper, but many different shapes and structures can result, which is exactly in line with the principle that a metamaterials' properties come from structure rather than composition," he explains.

 

Chen and colleagues in the US and the Netherlands were inspired by the novel idea of "topological mechanics", developed in 2014 by Charles Kane and Tom Lubensky from the University of Pennsylvania. Originating from the topological states seen in quantum physics, the idea was extended by Kane and Lubensky, who showed that there is a special class of mechanical structures that can be "polarized" so they are soft or floppy along one side, while being hard or rigid along the other.

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Scientists have just discovered a new state of matter

Scientists have just discovered a new state of matter | Amazing Science | Scoop.it

Researchers have just discovered evidence of a mysterious new state of matter in a real material. The state is known as 'quantum spin liquid' and it causes electrons - one of the fundamental, indivisible building blocks of matter - to break down into smaller quasiparticles.

 

Scientists had first predicted the existence of this state of matter in certain magnetic materials 40 years ago, but despite multiple hints of its existence, they've never been able to detect evidence of it in nature. So it's pretty exciting that they've now caught a glimpse of quantum spin liquid, and the bizarre fermions that accompany it, in a two-dimensional, graphene-like material.

 

"This is a new quantum state of matter, which has been predicted but hasn't been seen before," said one of the researchers, Johannes Knolle, from the University of Cambridge in the UK. They were able to spot evidence of quantum spin liquid in the material by observing one of its most intriguing properties - electron fractionalization - and the resulting Majorana fermions, which occur when electrons in a quantum spin state split apart. These Majorana fermions are exciting because they could be used as building blocks of quantum computers.

 

To be clear, the electrons aren't actually splitting down into smaller physical particles - which of course would be an even bigger deal since that would mean brand new particles! What's happening instead is the new state of matter is breaking electrons down into quasiparticles. These aren't actually real particles, but are concepts used by physicists to explain and calculate the strange behavior of particles.

 

And the quantum spin liquid state is definitely making electrons act weirdly - in a typical magnetic material, electrons behave like tiny bar magnets. So when the material is cooled to a low enough temperature, these magnet-like electrons order themselves over long ranges, so that all the north magnetic poles point in the same direction.

 

But in a material containing a quantum spin liquid state, even if a magnetic material is cooled to absolute zero, the electrons don't align, but instead form an entangled soup caused by quantum fluctuations.

 

"Until recently, we didn't even know what the experimental fingerprints of a quantum spin liquid would look like," said one of the researchers, Dmitry Kovrizhin. "One thing we've done in previous work is to ask, if I were performing experiments on a possible quantum spin liquid, what would I observe?"

 


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No more washing: Nano-enhanced textiles clean themselves with light

No more washing: Nano-enhanced textiles clean themselves with light | Amazing Science | Scoop.it

Researchers at RMIT University in Melbourne, Australia, have developed a cheap and efficient new way to grow special nanostructures—which can degrade organic matter when exposed to light—directly onto textiles.

 

The work paves the way towards nano-enhanced textiles that can spontaneously clean themselves of stains and grime simply by being put under a light bulb or worn out in the sun.

 

Dr Rajesh Ramanathan said the process developed by the team had a variety of applications for catalysis-based industries such as agrochemicals, pharmaceuticals and natural products, and could be easily scaled up to industrial levels.

 

"The advantage of textiles is they already have a 3D structure so they are great at absorbing light, which in turn speeds up the process of degrading organic matter," he said.

 

"There's more work to do to before we can start throwing out our washing machines, but this advance lays a strong foundation for the future development of fully self-cleaning textiles."

 

The researchers from the Ian Potter NanoBioSensing Facility and NanoBiotechnology Research Lab at RMIT worked with copper and silver-based nanostructures, which are known for their ability to absorb visible light.

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Breakthrough for cheaper lighting and flexible solar cells

Breakthrough for cheaper lighting and flexible solar cells | Amazing Science | Scoop.it

In more than three years of work european scientists finally made future lighting technology ready to market. They developed flexible lighting foils that can be produced roll-to-roll -- much like newspapers are printed. These devices pave the path towards cheaper solar cells and LED lighting panels. The project named TREASORES was lead by Empa scientist Frank Nüesch and combined knowhow from nine companies and six research institutes in five european countries.

 

In November 2012, the TREASORES project (Transparent Electrodes for Large Area Large Scale Production of Organic Optoelectronic Devices) started with the aim of developing technologies to dramatically reduce the production costs of organic electronic devices such as solar cells and LED lighting panels. Funded with 9 million Euro from the European Commission and an additional 6 million Euros from the project partners, the project has since then produced seven patent applications, a dozen peer-reviewed publications and provided inputs to international standards organisations.

 

Most importantly, the project has developed and scaled up production processes for several new transparent electrode and barrier materials for use in the next generation of flexible optoelectronics. Three of these electrodes-on-flexible substrates that use either carbon nanotubes, metal fibres or thin silver are either already being produced commercially, or expected to be so as of this year. The new electrodes have been tested with several types of optoelectronic devices using rolls of over 100 meters in length, and found to be especially suitable for next-generation light sources and solar cells.

 

The roll of OLED light sources with the project logo was made using roll-to-roll techniques at Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology (Fraunhofer FEP) on a thin silver electrode developed within the project by Rowo Coating GmbH. Such processing techniques promise to make light sources and solar cells much cheaper in future, but require flexible and transparent electrodes and water impermeable barriers -- which have also been developed by the TREASORES project. The electrodes from the project are technically at least as good as those currently used (made from indium tin oxide, ITO) but will be cheaper to manufacture and do not rely on the import of indium.

 

Tomasz Wanski from the Fraunhofer FEP said that because of the new electrodes, the OLED light source was very homogeneous over a large area, achieving an efficiency of 25 lumens per watt -- as good as the much slower sheet to sheet production process for equivalent devices. In the course of the project, new test methods were developed by the National Physical Laboratory in the UK to make sure that the electrodes would still work after being repeatedly bent -- a test that may become a standard in the field.

 

A further outcome of the project has been the development, testing and production scale-up of new approaches to transparent barrier foils (plastic layers that prevent oxygen and water vapour from reaching the sensitive organic electronic devices). High performance low-cost barriers were produced and it is expected that the Swiss company Amcor Flexibles Kreuzlingen will adopt this technology after further development. Such high performance barriers are essential to achieve the long device lifetimes that are necessary for commercial success -- as confirmed by a life cycle analysis (LCA) completed during the project, solar cells are only economically or ecologically worthwhile if both their efficiency and lifetime are high enough. By combining the production of barriers with electrodes (instead of using two separate plastic substrates), the project has shown that production costs can be further reduced and devices made thinner and more flexible.

 

The main challenge the project had to face was to make the barrier and electrode foils extremely flat, smooth and clean. Optoelectronic devices have active layers of only a few hundred nanometres (less than one percent of the width of a human hair), and even small surface irregularities or invisibly tiny dust particles can ruin the device yield or lead to uneven illumination and short lifetimes.

 

The TREASORES project united nine companies with six research institutes from five countries and was led by Frank Nüesch from the Swiss Federal Laboratories for Materials Science and Technology (Empa). "I am very much looking forward to seeing the first commercial products made using materials from the project in 2016," says Nüesch.

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Scientists create painless patch of insulin-producing beta cells to control diabetes

Scientists create painless patch of insulin-producing beta cells to control diabetes | Amazing Science | Scoop.it

For decades, researchers have tried to duplicate the function of beta cells, which don't work properly in patients with diabetes. Now, researchers have devised another option: a synthetic patch filled with natural beta cells that can secrete doses of insulin to control blood sugar levels on demand.

 

Now, researchers at the University of North Carolina at Chapel Hill and North Carolina State University have devised another option: a synthetic patch filled with natural beta cells that can secrete doses of insulin to control blood sugar levels on demand with no risk of inducing hypoglycemia.

 

The proof-of-concept builds on an innovative technology, the "smart insulin patch," reported last year in the Proceedings of the National Academy of Sciences. Both patches are thin polymeric squares about the size of a quarter and covered in tiny needles, like a miniature bed of nails. But whereas the former approach filled these needles with manmade bubbles of insulin, this new "smart cell patch" integrates the needles with live beta cells.

 

Tests of this painless patch in small animal models of type-1 diabetes demonstrated that it could quickly respond to skyrocketing blood sugar levels and significantly lower them for 10 hours at a time. The results were published in Advanced Materials.

 

"This study provides a potential solution for the tough problem of rejection, which has long plagued studies on pancreatic cell transplants for diabetes," said senior author Zhen Gu, PhD, assistant professor in the joint UNC/NC State department of biomedical engineering. "Plus it demonstrates that we can build a bridge between the physiological signals within the body and these therapeutic cells outside the body to keep glucose levels under control."

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Down the rabbit hole: How electrons travel through exotic new material

Down the rabbit hole: How electrons travel through exotic new material | Amazing Science | Scoop.it

Researchers at Princeton University have observed a bizarre behavior in a strange new crystal that could hold the key for future electronic technologies.

 

"It is like these electrons go down a rabbit hole and show up on the opposite surface," said Ali Yazdani, the Class of 1909 Professor of Physics. "You don't find anything else like this in other materials." The research was published in the journal Science.

 

Yazdani and his colleagues discovered the odd behavior while studying electrons in a crystal made of layers of tantalum and arsenic. The material, called a Weyl semi-metal, behaves both like a metal, which conducts electrons, and an insulator, which blocks them. A better understanding of these and other "topological" materials someday could lead to new, faster electronic devices.

 

The team's experimental results suggest that the surface electrons plunge into the crystal only when traveling at a certain speed and direction of travel called the Weyl momentum, said Yazdani. "It is as if you have an electron on one surface, and it is cruising along, and when it hits some special value of momentum, it sinks into the crystal and appears on the opposite surface," he said.

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You can now 3D print one of the world’s lightest materials

You can now 3D print one of the world’s lightest materials | Amazing Science | Scoop.it

Aerogels are among the world’s lightest materials. Graphene aerogel, a record holder in that category, is so light that a large block of it wouldn’t make a dent on a tiny ball of cotton. Water is about one thousand times more dense. The minimal density of aerogels allows for a number of possible applications, researchers have found, ranging from soaking up oil spills to “invisibility” cloaks.

 

Now, scientists from State University of New York (SUNY) at Buffalo and Kansas State University report in the journal Small that they have found a way to 3D print graphene aerogel, which has only been used in lab prototypes. This technology will make the material much easier to use, and open it, and hopefully other aerogel materials, up to wider applications.

 

Graphene is just a single layer of carbon atoms. Since it was isolated for the first time in 2004, it has been touted as a wonder material for its strength, pliability and conductivity. Aerogel is essentially a gel where the liquid is replaced by air. Graphene aerogel is known to be highly compressible (so it can bear pressure without breaking apart) and highly conductive (so it can carry electricity efficiently). The very structure of the material that gives it these properties, however, makes it difficult to manufacture using 3D printing technology.

 

SUNY Buffalo and Kansas State University researchers came up with a solution. They mixed graphene oxide—graphene with extra oxygen atoms—with water and deposited layers on a surface at -25°C. This instantly froze each layer, and allowed the undisrupted construction of the aerogel, with ice as its support.

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Miro Svetlik's curator insight, March 3, 10:14 AM
3D Printing aerogels containing graphene? This material gets some interesting properties. While it is quite hard to manufacture in a controlled fashion I believe it will open the way for compressible circuits.
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Absorbing acoustics with soundless spirals

Absorbing acoustics with soundless spirals | Amazing Science | Scoop.it

Researchers at the French National Centre for Scientific Research, CNRS, and the University of Lorraine have recently developed a design for a coiled-up acoustic metasurface which can achieve total acoustic absorption in very low-frequency ranges. "The main advantage is the deep-subwavelength thickness of our absorber, which means that we can deal with very low-frequencies - meaning very large wavelengths - with extremely reduced size structure," said Badreddine Assouar, a principal research scientist at CNRS in Nancy, France.


Assouar and Li, a post-doc in his group at the Institut Jean Lamour, affiliated with the CNRS and the University of Lorraine, describe their work this week in Applied Physics Letters from AIP Publishing.


Acoustic absorption systems work by absorbing sound energy at a resonant frequency and dissipating it into heat. Traditional acoustic absorbers consist of specially perforated plates placed in front of hard objects to form air cavities; however, in order to operate at low frequencies, these systems must also be relatively thick in length, which makes them physically impractical for most applications.


To remedy this, Assouar's group, whose previous work consisted of developing coiled channel systems, designed an acoustic absorber in which sound waves enter an internal coiled air channel through a perforated center hole. This forces the acoustic waves to travel through the channel, effectively increasing the total propagation length of the waves and leading to an effective low sound velocity and high acoustic refractive index. This allows them to make the absorber itself relatively thin, while still maintaining the absorptive properties of a much thicker chamber.


This is made possible because the coiled chamber's acoustic reactance - a property analogous to electrical reactance, a circuit's opposition to a change in voltage or current - compensates for the reactance of the perforated hole and allows for impedance matching to be achieved. This causes all of the acoustic energy to be transferred to the chamber, rather than reflected, and to be ultimately absorbed within the perforated hole.


Further applications of such metasurface may deal with the realization of tunable amplitude and phase profile for acoustic engineering, which would allow for the manipulation of an acoustic wave's propagation trajectory for special applications, such as manipulating particles with a vortex wavefront. Future work for Assouar and his group will include developing the sample fabrication process with 3D printing and subsequent performance analyses.


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What is ferromagnetic and harder than diamond? Q-carbon, a new carbon allotrope

What is ferromagnetic and harder than diamond? Q-carbon, a new carbon allotrope | Amazing Science | Scoop.it
A team of material scientists in the United States has discovered a novel allotrope of carbon, Q-carbon.


Q-carbon is distinct from graphite and diamond. The only place it may be found in the natural world would be possibly in the core of some planets, according to team leader Prof. Jagdish Narayan, of North Carolina State University. The new carbon allotrope has some unusual characteristics: it is ferromagnetic, harder than diamond, and it glows when exposed to low levels of energy.


“Q-carbon’s strength and low work-function – its willingness to release electrons – make it very promising for developing new electronic display technologies,” Prof. Narayan explained. Prof. Narayan and his colleague, North Carolina State University Ph.D. student Anagh Bhaumik, have also developed a technique for using Q-carbon to make diamond-related structures at room temperature and at ambient atmospheric pressure in air.


To produce Q-carbon, the material scientists start with a glass or sapphire substrate. The substrate is then coated with an amorphous metastable phase of carbon, where bonding characteristics are a mixture of graphite and diamond.


The carbon is then hit with a single KrF laser pulse lasting 200 nanoseconds. During this pulse, the temperature of the carbon is raised to 6,740 degrees Fahrenheit (3,727 degrees Celsius) and then rapidly cooled. This operation takes place at one atmosphere – the same pressure as the surrounding air. The end result is a film of Q-carbon, and scientists can control the process to make films between 20 nanometers and 500 nanometers thick. By using different substrates and changing the duration of the laser pulse, they can also control how quickly the carbon cools. By changing the rate of cooling, they are able to create diamond structures within the Q-carbon.


“We can create diamond nanoneedles or microneedles, nanodots, or large-area diamond films, with applications for drug delivery, industrial processes and for creating high-temperature switches and power electronics,” Prof. Narayan explained. Bhaumik and Prof. Narayan reported their results in a pair of papers in theJournal of Applied Physics and the journal APL Materials.

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Switchable material could enable new memory chips

Switchable material could enable new memory chips | Amazing Science | Scoop.it

Two MIT researchers have developed a thin-film material whose phase and electrical properties can be switched between metallic and semiconducting simply by applying a small voltage. The material then stays in its new configuration until switched back by another voltage.


The discovery could pave the way for a new kind of “nonvolatile” computer memory chip that retains information when the power is switched off, and for energy conversion and catalytic applications.

The findings, reported in the journal Nano Letters in a paper by MIT materials science graduate student Qiyang Lu and associate professor Bilge Yildiz, involve a thin-film material called a strontium cobaltite, or SrCoOx.


Usually, Yildiz says, the structural phase of a material is controlled by its composition, temperature, and pressure. “Here for the first time,” she says, “we demonstrate that electrical bias can induce a phase transition in the material. And in fact we achieved this by changing the oxygen content in SrCoOx.”


“It has two different structures that depend on how many oxygen atoms per unit cell it contains, and these two structures have quite different properties,” Lu explains. One of these configurations of the molecular structure is called perovskite, and the other is called brownmillerite. When more oxygen is present, it forms the tightly-enclosed, cage-like crystal structure of perovskite, whereas a lower concentration of oxygen produces the more open structure of brownmillerite.


The two forms have very different chemical, electrical, magnetic, and physical properties, and Lu and Yildiz found that the material can be flipped between the two forms with the application of a very tiny amount of voltage — just 30 millivolts (0.03 volts). And, once changed, the new configuration remains stable until it is flipped back by a second application of voltage.


Strontium cobaltites are just one example of a class of materials known as transition metal oxides, which is considered promising for a variety of applications including electrodes in fuel cells, membranes that allow oxygen to pass through for gas separation, and electronic devices such as memristors — a form of nonvolatile, ultrafast, and energy-efficient memory device. The ability to trigger such a phase change through the use of just a tiny voltage could open up many uses for these materials, the researchers say.


Previous work with strontium cobaltites relied on changes in the oxygen concentration in the surrounding gas atmosphere to control which of the two forms the material would take, but that is inherently a much slower and more difficult process to control, Lu says. “So our idea was, don’t change the atmosphere, just apply a voltage.”


“Voltage modifies the effective oxygen pressure that the material faces,” Yildiz adds. To make that possible, the researchers deposited a very thin film of the material (the brownmillerite phase) onto a substrate, for which they used yttrium-stabilized zirconia.


In that setup, applying a voltage drives oxygen atoms into the material. Applying the opposite voltage has the reverse effect. To observe and demonstrate that the material did indeed go through this phase transition when the voltage was applied, the team used a technique called in-situ X-ray diffraction at MIT’s Center for Materials Science and Engineering.

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New polymer developed that can “remember” and shapeshift

New polymer developed that can “remember” and shapeshift | Amazing Science | Scoop.it
3D printing has truly evolved in the past year, but did you know that some 3D printers can even recreate the complex shapes of origami? But, what if you wanted to unfold your 3D printed crane or lotus flower and refold it into something else? This is easy using paper, but more difficult using the hard plastic of 3D printing.


Research by Qian Zhao and colleagues, published in the journal Science Advancesdetails a new method involving shape memory polymers, a unique class of polymers that can be “programmed” to assume certain shapes. After the polymer is programmed, its shape can be temporarily altered by subsequent heating. However, upon cooling, the polymer will return to its programmed shape, a process known as recovery. In other words, the plastic “remembers” the shape it was originally programmed to achieve.


Although this is a useful ability in itself, what if we wanted to change the programmed shape after it is already programmed, like unfolding  a crane origami and refolding  it into a lotus flower? Here, the authors revealed their experiments with a cross-linked polycaprolactone polymer system. This polymer showed a large degree of plasticity, meaning that it could be programmed to “remember” one shape, and then reprogrammed to remember another. In addition, this material can show cumulative plasticity, the ability to retain some of the characteristics of previously-programmed shapes, even when its shape is later changed to something completely different!


The unprecedented flexibility is shown in their first experiment, where a flat, square-shaped film was programmed to assume the shape of an origami bird. When heated, the bird became “elastic”, meaning it could be deformed into various temporary shapes, such as a plane.  Upon cooling, however, the polymer would return to the programmed bird shape. As describe above, this ability is not new. However, using a transesterification reaction catalyzed by a neutralized organic base, the authors were able to reprogram the recovered bird into a drastically different permanent structure – that of an origami sailboat. This boat, in turn, could be heated to create new temporary shapes, such as a windmill. Upon cooling, the shape then recovered to the sailboat shape.


In their next experiment, they programmed a flat film of polymer five consecutive times. During the first four deformations, the film was given different surface features by stretching and embossing. Each plastic deformation built on the previous one, creating a progressively more complicated pattern on the surface of the film.  In the last stage, the film was programmed to roll into a tube so that the surface pattern lined the inside of the tube. Therefore, one could even add textures on surfaces that aren’t actually accessible in the final shape.

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Miro Svetlik's curator insight, January 17, 5:02 AM

New materials are new frontier of 3D printing I believe. Advances we can make with new materials will be differentiators in 3D printing industry in next decade.

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A Super-Stretchy Self-Healing Artificial Muscle Can Stretch From 1 inch to over 8 feet

A Super-Stretchy Self-Healing Artificial Muscle Can Stretch From 1 inch to over 8 feet | Amazing Science | Scoop.it

When you pull a muscle, it may hurt like heck for a while, but the human body can heal. The same is not true of the electrically-responsive polymers used to make artificial muscles for haptic systems and experimental robots. When they get cut or punctured, it’s game over. A new polymer that’s super stretchy and self-healing can act as a more resilient artificial muscle material. Created by a team led by Stanford University materials scientist Zhenan Bao, the polymer has an unusual combination of properties. A 2.5-centimeter sheet of the stuff can be stretched out to a length of 2.5 meters. When it’s punctured it fuses back together, something other self-healing materials don’t do well in ambient conditions.

 

This version of the material is not going to power a robot to win any weight-lifiting contests: it generates just a small amount of force, expanding by 3.6 percent under an electric field of 17.2 millivolts per meter. The muscle expands in one dimension, contracting in the other two. Artificial muscles contract in response to an electric field, similar to biological muscles, but they’re typically made of polymers. They’re found in some cell phone haptic feedback systems. They can also be used to make robot appendages move and to push up and down the Braille dots in displays for people with low vision.

 

“Artificial muscles are typically very sensitive to defects and pinholes—they really affect their actuation performance,” says Bao.  The Stanford group wanted to make artificial muscles that would more readily heal. Bao is known for developing more sensitive, more life-like electronic skin for robotics and prosthetics, and the new chemical design basics will help make better materials for those efforts. But she has a broader goal of learning how to better engineer multifunctional materials.

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Route to Carbyne: Scientists Create Ultra-Long 1D Carbon Chains

Route to Carbyne: Scientists Create Ultra-Long 1D Carbon Chains | Amazing Science | Scoop.it

Even in its elemental form, the high bond versatility of carbon allows for many different well-known materials, including diamond and graphite. A single layer of graphite, named graphene, can then be rolled or folded into carbon nanotubes or fullerenes, respectively. To date, Nobel prizes have been awarded for both graphene and fullerenes.

 

Although the existence of carbyne, an infinitely long carbon chain, was proposed in 1885 by Adolf von Baeyer, scientists have not yet been able to synthesize this material. Von Baeyer even suggested that carbyne (also known as linear acetylenic carbon) would remain elusive as its high reactivity would always lead to its immediate destruction. Nevertheless, carbon chains of increasing length have been successfully synthesized over the last five decades, with a record of around 100 carbon atoms.

To grow even longer carbon chains – up to 6,000 carbon atoms long – on a bulk scale, Dr. Pichler and his colleagues used the confined space inside a double-walled carbon nanotube as a nano-reactor.

 

“The direct experimental proof of confined ultra-long linear carbon chains, which are more than an order of magnitude longer than the longest proven chains so far, can be seen as a promising step towards the final goal of unraveling the ‘holy grail’ of carbon allotropes, carbyne,” said team member Lei Shi, from the Faculty of Physics at the University of Vienna. “Carbyne is very stable inside double-walled carbon nanotubes,” the scientists said. “This property is crucial for its eventual application in future materials and devices.”

 

“According to theoretical models, carbyne’s mechanical properties exceed all known materials, outperforming both graphene and diamond.”

 

“Carbyne’s electrical properties suggest novel nanoelectronic applications in quantum spin transport and magnetic semiconductors.” The results were published online April 4, 2016 in the journal Nature Materials (arXiv.org preprint).

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Metal foam obliterates bullets – and that's just the beginning

Metal foam obliterates bullets – and that's just the beginning | Amazing Science | Scoop.it

Composite metal foams (CMFs) are tough enough to turn an armor-piercing bullet into dust on impact. Given that these foams are also lighter than metal plating, the material has obvious implications for creating new type of protection.

 

Afsaneh Rabiei, a professor of mechanical and aerospace engineering at NC State, has spent years developing CMFs and investigating their unusual properties. The video seen here shows a composite armor made out of her composite metal foams. The bullet in the video is a 7.62 x 63 millimeter M2 armor piercing projectile, which was fired according to the standard testing procedures established by the National Institute of Justice (NIJ). And the results were dramatic.

 

"We could stop the bullet at a total thickness of less than an inch, while the indentation on the back was less than 8 millimeters," Rabiei says. "To put that in context, the NIJ standard allows up to 44 millimeters indentation in the back of an armor." The results of that study were published in 2015.

 

But there are many applications that require a material to be more than just incredibly light and strong. For example, applications from space exploration to shipping nuclear waste require a material to be not only light and strong, but also capable of withstanding extremely high temperatures and blocking radiation.

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3-D printer and 'Gecko Grippers' head to space station

3-D printer and 'Gecko Grippers' head to space station | Amazing Science | Scoop.it

A United Launch Alliance Atlas 5 rocket loaded with supplies and science experiments blasted off from Florida on Tuesday, boosting an Orbital ATK cargo capsule toward the International Space Station.

 

The 194-foot (59-meter) rocket soared off its seaside launch pad at Cape Canaveral Air Force Station at 11:05 p.m. EDT/0305 GMT. United Launch Alliance is a partnership of Lockheed Martin and Boeing.

 

Perched on top of the rocket was a Cygnus capsule loaded with nearly 7,500 pounds (3,400 kg) of food, science experiments and equipment including a 3-D printer to build tools for astronauts and non-stick grippers modeled after gecko feet.

 

The printer works by heating plastic, metal or other materials into streams that are layered on top of each other to create three-dimensional objects.

 

“If we had a choice of what we could use that printer for, I’m sure we could be quite creative,” station commander Tim Kopra said during an inflight interview on Tuesday.

 

The experimental Gecko Gripper is a new kind of adhesive that mimics the way gecko lizards cling to surfaces without falling. It aims to test a method of attaching things in the weightless environment of space.

 

NASA is looking at robotic versions of gecko feet to attach sensors and other instruments onto and inside satellites.

The Gecko Gripper technology may lead to terrestrial versions of grippers that could, for example, hold flat-screen TVs to walls without anchoring systems and adhesives, said lead researcher Aaron Parness with NASA’s Jet Propulsion Laboratory in Pasadena, California.

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New Carbon Capture Membrane Boasts CO2 Highways | Berkeley Lab

New Carbon Capture Membrane Boasts CO2 Highways | Berkeley Lab | Amazing Science | Scoop.it

A new, highly permeable carbon capture membrane developed by scientists from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) could lead to more efficient ways of separating carbon dioxide from power plant exhaust, preventing the greenhouse gas from entering the atmosphere and contributing to climate change.

 

The researchers focused on a hybrid membrane that is part polymer and part metal-organic framework, which is a porous three-dimensional crystal with a large internal surface area that can absorb enormous quantities of molecules.

 

In a first, the scientists engineered the membrane so that carbon dioxide molecules can travel through it via two distinct channels. Molecules can travel through the polymer component of the membrane, like they do in conventional gas-separation membranes. Or molecules can flow through “carbon dioxide highways” created by adjacent metal-organic frameworks.

 

Initial tests show this two-route approach makes the hybrid membrane eight times more carbon dioxide permeable than membranes composed only of the polymer. Boosting carbon dioxide permeability is a big goal in efforts to develop carbon capture materials that are energy efficient and cost competitive.

 

The research is the cover article of the March issue of the journal Energy & Environmental Science. “In our membrane, some CO2 molecules get an express ride through the highways formed by metal-organic frameworks, while others take the polymer pathway. This new approach will enable the design of higher performing gas separation membranes,” says Norman Su, a graduate student in the Chemical and Biomolecular Engineering Department at UC Berkeley and a user at the Molecular Foundry.

 

He conducted the research with Jeff Urban, Facility Director of the Inorganic Nanostructures Facility at the Molecular Foundry, and a team of scientists that included staff at the Advanced Light Source.

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Russell R. Roberts, Jr.'s curator insight, March 21, 12:41 AM
The newly developed carbon capture membrane may be the answer to controlling the amount of carbon dioxide that enters our atmosphere from power plants, especially those using goal or other petroleum-based products.  This is something that is needed now to help reduce a gas that propels global warming.
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Tunable windows for privacy, camouflage

Tunable windows for privacy, camouflage | Amazing Science | Scoop.it

Researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences have developed a technique that can quickly change the opacity of a window, turning it cloudy, clear or somewhere in between with the flick of a switch.

 

Tunable windows aren’t new but most previous technologies have relied on electrochemical reactions achieved through expensive manufacturing.  This technology, developed by David Clarke, the Extended Tarr Family Professor of Materials, and postdoctoral fellow Samuel Shian, uses geometry adjust the transparency of a window.

 

The research is described in journal Optics Letters. The tunable window is comprised of a sheet of glass or plastic, sandwiched between transparent, soft elastomers sprayed with a coating of silver nanowires, too small to scatter light on their own.  

 

But apply an electric voltage and things change quickly. With an applied voltage, the nanowires on either side of the glass are energized to move toward each other, squeezing and deforming the soft elastomer. Because the nanowires are distributed unevenly across the surface, the elastomer deforms unevenly. The resulting uneven roughness causes light to scatter, turning the glass opaque. The change happens in less than a second.

It’s like a frozen pond, said Shian.

 

“If the frozen pond is smooth, you can see through the ice. But if the ice is heavily scratched, you can’t see through,” said Shian. 

 

Clarke and Shian found that the roughness of the elastomer surface depended on the voltage, so if you wanted a window that is only light clouded, you would apply less voltage than if you wanted a totally opaque window.

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Magnetic nanoparticles show promise in biomedical applications

Magnetic nanoparticles show promise in biomedical applications | Amazing Science | Scoop.it
Recent developments and research related to iron oxide nanoparticles confirm their potential in biomedical applications – such as targeted drug delivery – and the necessity for further studies.

 

Iron oxides are widespread in nature and can be readily synthesized in the laboratory. Among them, hematite, magnetite and maghemite nanoparticles have particularly promising properties for biomedical applications.

 

Researchers in China and Korea reviewed recent studies on the preparation, structure and magnetic properties of iron oxide nanoparticles (IONPs) and their corresponding applications. The review, published in the journal Science and Technology of Advanced Materials, emphasized that the size, size distribution (the relative proportions of different-sized particles in a given sample), shape and magnetic properties of IONPs affect the location and mobility of IONPs in the human body. However, having complete control over the shape and size distribution of magnetic IONPs remains a challenge. For example, magnetic IONPs are promising for carrying cancer drugs that target specific tissues. For this to happen, they are coated with a biocompatible shell that carries a specific drug. If this "functionalized" magnetic IONP is too large, it may be cleared from the blood stream. Thus, it is very important to be able to control the size of these particles. Researchers found that IONPs with diameters ranging from 10 to 100 nanometres are optimal for intravenous injection and can remain in the blood stream for the longest period of time.

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A foldable material that can change size, volume and shape

A foldable material that can change size, volume and shape | Amazing Science | Scoop.it

Harvard researchers have designed a new type of foldable material that is versatile, tunable and self actuated. It can change size, volume and shape; it can fold flat to withstand the weight of an elephant without breaking, and pop right back up to prepare for the next task.

 

The research was lead by Katia Bertoldi, the John L. Loeb Associate Professor of the Natural Sciences at the John A. Paulson School of Engineering and Applied Sciences (SEAS), James Weaver, Senior Research Scientist at the Wyss Institute for Biologically Inspired Engineering at Harvard University and Chuck Hoberman, of the Graduate School of Design. It is described in Nature Communications.

 

"We've designed a three-dimensional, thin-walled structure that can be used to make foldable and reprogrammable objects of arbitrary architecture, whose shape, volume and stiffness can be dramatically altered and continuously tuned and controlled," said Johannes T. B. Overvelde, graduate student in Bertoldi's lab and first author of the paper. The structure is inspired by an origami technique called snapology, and is made from extruded cubes with 24 faces and 36 edges. Like origami, the cube can be folded along its edges to change shape. The team demonstrated, both theoretically and experimentally, that the cube can be deformed into many different shapes by folding certain edges, which act like hinges. The team embedded pneumatic actuators into the structure, which can be programmed to deform specific hinges, changing the cube's shape and size, and removing the need for external input.

 

The team connected 64 of these individual cells to create a 4x4x4 cube that can grow, and shrink, change its shape globally, change the orientation of its microstructure and fold completely flat. As the structure changes shape, it also changes stiffness -- meaning one could make a material that's very pliable or very stiff using the same design. These actuated changes in material properties adds a fourth dimension to the material.

 

"We not only understand how the material deforms, but also have an actuation approach that harnesses this understanding," said Bertoldi. "We know exactly what we need to actuate in order to get the shape we want."

 


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New research unveils graphene 'moth eyes' to power future smart technologies

New research unveils graphene 'moth eyes' to power future smart technologies | Amazing Science | Scoop.it
New research published today in Science Advances has shown how graphene can be manipulated to create the most light-absorbent material for its weight, to date.


Graphene is traditionally an excellent electronic material, but is inefficient for optical applications, absorbs only 2.3% of the light incident on it. A new technique enhances light absorption by 90%.

New research published today in Science Advances has shown how graphene can be manipulated to create the most light-absorbent material for its weight, to date. This nanometre-thin material will enable future applications such as 'smart wallpaper' that could generate electricity from waste light or heat, and power a host of applications within the growing 'internet of things'.


Using a technique known as nanotexturing, which involves growing graphene around a textured metallic surface, researchers from the University of Surrey's Advanced Technology Institute took inspiration from nature to create ultra-thin graphene sheets designed to more effectively capture light. Just one atom thick, graphene is very strong but traditionally inefficient at light absorption. To combat this, the team used the nano-patterning to localise light into the narrow spaces between the textured surface, enhancing the amount of light absorbed by the material by about 90%.


"Nature has evolved simple yet powerful adaptations, from which we have taken inspiration in order to answer challenges of future technologies," explained Professor Ravi Silva, Head of the Advanced Technology Institute.


"Moths' eyes have microscopic patterning that allows them to see in the dimmest conditions. These work by channelling light towards the middle of the eye, with the added benefit of eliminating reflections, which would otherwise alert predators of their location. We have used the same technique to make an amazingly thin, efficient, light-absorbent material by patterning graphene in a similar fashion."


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Gloop from the deep sea: The unusual secretions of the hagfish

Gloop from the deep sea: The unusual secretions of the hagfish | Amazing Science | Scoop.it

ETH scientists are researching the unusual secretions of the hagfish. Over the next three years, the researchers will try to find out how this natural hydrogel can be harnessed for human use.


This animal has done everything right. It has been around for 300 million years, outlived the dinosaurs and survived the catastrophic meteorite impact, warm phases and glacial periods. Even today, it continues to populate the sea at depths where it eats carrion and hunts prey. The Atlantic hagfish (Myxine glutinosa) is not really attractive at first glance. In fact, most people probably consider it quite disgusting. Nevertheless, the hagfish – or rather its slime – has caught the attention of a group of ETH researchers at the Laboratory of Food Process Engineering.


The slime of the hagfish is an extraordinary defense mechanism. When a hagfish is attacked by a predator, it secretes a glandular exudate that gels within a split second and forms a massive slime mass – even in cold water. This slime immobilizes vast amounts of water, forming a dilute, viscous and cohesive network. Fish attempting to attack the hagfish may then suffocate on the slime and thus let go of the hagfish.


Preliminary research quickly revealed to the scientists that there had been little examination of the structure of the slime and how it is formed and secreted. The scientific community knows that the natural hydrogel produced by the hagfish has two main components: 15- to 30-cm-long protein threads and mucin, which sits between the threads and makes the slime “slimy”. The protein threads have properties similar to spider silk. According to Kuster, the threads are extremely tear-resistant and elastic, though only when moist.


The slime consists of almost 100 % water and contains just 0.004 % gelling agent. In other words, the weight ratio of gelling agent to water is 26,000-fold, which is over 200 times more than in conventional animal gelatine. Furthermore, very little energy is required for the gelling process.


The ETH researchers were especially fascinated by the fact that the protein filaments have the form of a sphere measuring 150 micrometers in diameter while still in the glands, but once they are part of the slime they extend to threads of several centimeters in length. How the threads unwind from the sphere is not yet understood in depth. "The way the threads coil within the cells is highly specialized and very unusual," says Böni.

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Block Copolymers Form Self-Stacking Nanogrids

Block Copolymers Form Self-Stacking Nanogrids | Amazing Science | Scoop.it

Since the 1960s, computer chips have been built using a process called photolithography. But in the past five years, chip features have gotten smaller than the wavelength of light, which has required some ingenious modifications of photolithographic processes. Keeping up the rate of circuit miniaturization that we’ve come to expect — as predicted by Moore’s Law — will eventually require new manufacturing techniques.


Block copolymers, molecules that spontaneously self-assemble into useful shapes, are one promising alternative to photolithography. In a new paper in the journal Nature Communications, MIT researchers describe the first technique for stacking layers of block-copolymer wires such that the wires in one layer naturally orient themselves perpendicularly to those in the layer below.


The ability to easily produce such “mesh structures” could make self-assembly a much more practical way to manufacture memory, optical chips, and even future generations of computer processors.

“There is previous work on fabricating a mesh structure — for example our work,” says Amir Tavakkoli, a postdoc in MIT’s Research Laboratory of Electronics and one of three first authors on the new paper.


“We used posts that we had fabricated by electron-beam lithography, which is time consuming. But here, we don’t use the electron-beam lithography. We use the first layer of block copolymer as a template to self-assemble another layer of block copolymer on top of it.”


Tavakkoli’s co-first-authors on the paper are Sam Nicaise, a graduate student in electrical engineering, and Karim Gadelrab, a graduate student in materials science and engineering. The senior authors are Alfredo Alexander-Katz, the Walter Henry Gale Associate Professor of Materials Science and Engineering; Caroline Ross, the Toyota Professor of Materials Science and Engineering; and Karl Berggren, a professor of electrical engineering.


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North Face's New Jacket is Made From Synthetic Spider’s Silk

North Face's New Jacket is Made From Synthetic Spider’s Silk | Amazing Science | Scoop.it

"Spider's silk is as strong as steel, lighter than carbon fibre and tougher than Kevlar.  Several research groups are hoping harness these remarkable properties by creating synthetic versions of the material.

Now, North Face has partnered with one of these teams to create a jacket made from a fiber named 'Qmonos' – the Japanese word for spider."


The prototype jacket, dubbed the 'Moon Parka', is the work of Japanese advanced biomaterials company Spiber. North Face describes it as 'the world's first piece of clothing made from artificial protein material.'


Spiber's manmade version uses synthesised genes which coax bacteria to produce fibroin, a structural protein found in spider silk. Spiber then uses the technology to culture the microbes efficiently and weave the fibroin into fabric. Spiber is remaining tight lipped about the exact process. But the company did say that the proteins are created through a microbial fermentation process.


'Our team has extensively studied the diverse genetic designs found in nature,' Spiber's Vimeo video says. 'We've developed advanced methods to create new, tailor-made protein materials designed at the molecular level.'


The team chose to make the coat in gold hue - the natural web colour of the golden orb spider. Goldwin, which markets The North Face in Japan, said the production process of the material is more environmentally-friendly that traditional petroleum-based polymer fibers.


There are already a number of garments made from real spider's silk, but these are rare, because spider's generally kill each other when confined. Spiders also only produce minute amounts of silk, spinning only what they need for a web, then consuming any excess it has 'spun'.


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