Tag Archives: University of Manchester

Creating quantum dots (artificial atoms) in graphene

An Aug. 22, 2016 news item on phys.org describes some recent work on artificial atoms and graphene from the Technical University of Vienna (Austria) and partners in Germany and the UK,

In a tiny quantum prison, electrons behave quite differently as compared to their counterparts in free space. They can only occupy discrete energy levels, much like the electrons in an atom – for this reason, such electron prisons are often called “artificial atoms”. Artificial atoms may also feature properties beyond those of conventional ones, with the potential for many applications for example in quantum computing. Such additional properties have now been shown for artificial atoms in the carbon material graphene. The results have been published in the journal Nano Letters, the project was a collaboration of scientists from TU Wien (Vienna, Austria), RWTH Aachen (Germany) and the University of Manchester (GB).

“Artificial atoms open up new, exciting possibilities, because we can directly tune their properties”, says Professor Joachim Burgdörfer (TU Wien, Vienna). In semiconductor materials such as gallium arsenide, trapping electrons in tiny confinements has already been shown to be possible. These structures are often referred to as “quantum dots”. Just like in an atom, where the electrons can only circle the nucleus on certain orbits, electrons in these quantum dots are forced into discrete quantum states.

Even more interesting possibilities are opened up by using graphene, a material consisting of a single layer of carbon atoms, which has attracted a lot of attention in the last few years. “In most materials, electrons may occupy two different quantum states at a given energy. The high symmetry of the graphene lattice allows for four different quantum states. This opens up new pathways for quantum information processing and storage” explains Florian Libisch from TU Wien. However, creating well-controlled artificial atoms in graphene turned out to be extremely challenging.

Florian Libisch, explaining the structure of graphene. Courtesy Technical University of Vienna

Florian Libisch, explaining the structure of graphene. Courtesy Technical University of Vienna

An Aug. 22, 2016 Technical University of Vienna press release (also on EurekAlert), which originated the news item, provides more detail,

There are different ways of creating artificial atoms: The simplest one is putting electrons into tiny flakes, cut out of a thin layer of the material. While this works for graphene, the symmetry of the material is broken by the edges of the flake which can never be perfectly smooth. Consequently, the special four-fold multiplicity of states in graphene is reduced to the conventional two-fold one.

Therefore, different ways had to be found: It is not necessary to use small graphene flakes to capture electrons. Using clever combinations of electrical and magnetic fields is a much better option. With the tip of a scanning tunnelling microscope, an electric field can be applied locally. That way, a tiny region is created within the graphene surface, in which low energy electrons can be trapped. At the same time, the electrons are forced into tiny circular orbits by applying a magnetic field. “If we would only use an electric field, quantum effects allow the electrons to quickly leave the trap” explains Libisch.

The artificial atoms were measured at the RWTH Aachen by Nils Freitag and Peter Nemes-Incze in the group of Professor Markus Morgenstern. Simulations and theoretical models were developed at TU Wien (Vienna) by Larisa Chizhova, Florian Libisch and Joachim Burgdörfer. The exceptionally clean graphene sample came from the team around Andre Geim and Kostya Novoselov from Manchester (GB) – these two researchers were awarded the Nobel Prize in 2010 for creating graphene sheets for the first time.

The new artificial atoms now open up new possibilities for many quantum technological experiments: “Four localized electron states with the same energy allow for switching between different quantum states to store information”, says Joachim Burgdörfer. The electrons can preserve arbitrary superpositions for a long time, ideal properties for quantum computers. In addition, the new method has the big advantage of scalability: it should be possible to fit many such artificial atoms on a small chip in order to use them for quantum information applications.

Here’s a link to and a citation for the paper,

Electrostatically Confined Monolayer Graphene Quantum Dots with Orbital and Valley Splittings by Nils M. Freitag, Larisa A. Chizhova, Peter Nemes-Incze, Colin R. Woods, Roman V. Gorbachev, Yang Cao, Andre K. Geim, Kostya S. Novoselov, Joachim Burgdörfer, Florian Libisch, and Markus Morgenstern. Nano Lett., Article ASAP DOI: 10.1021/acs.nanolett.6b02548 Publication Date (Web): July 28, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

Dexter Johnson in an Aug. 23, 2016 post on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website) provides some additional insight into the world of quantum dots,

Quantum dots made from semiconductor materials, like silicon, are beginning to transform the display market. While it is their optoelectronic properties that are being leveraged in displays, the peculiar property of quantum dots that allows their electrons to be forced into discrete quantum states has long held out the promise of enabling quantum computing.

If you have time to read it, Dexter’s post features an email interview with Florian Libisch where they further discuss quantum dots and quantum computing.

Improving fossil-fueled cars’ efficiency with graphene-based ballistic rectifier

UK and Chinese researchers have a developed a technology to make fuel use more efficient in fossil-fueled cars (from a June 2, 2016 news item on phys.org),

A graphene-based electrical nano-device has been created which could substantially increase the energy efficiency of fossil fuel-powered cars.

The nano-device, known as a ‘ballistic rectifier’, is able to convert heat which would otherwise be wasted from the car exhaust and engine body into a useable electrical current.

Parts of car exhausts can reach temperatures of 600 degrees Celsius. The recovered energy can then be used to power additional automotive features such as air conditioning and power steering, or be stored in the car battery.

The nano-rectifier was built by a team at The University of Manchester led by Professor Aimin Song and Dr. Ernie Hill, with a team at Shandong University. The device utilises graphene’s phenomenally high electron mobility, a property which determines how fast an electron can travel in a material and how fast electronic devices can operate.

A June 1, 2016 University of Manchester press release, which originated the news item, provides more detail,

The resulting device is the most sensitive room-temperature rectifier ever made. Conventional devices with similar conversion efficiencies require cryogenically low temperatures.

Even today’s most efficient internal combustion engines can only convert about 70% of energy burned from fossil fuels into the energy required to power a car. The rest of the energy created is often wasted through exhaust heat or cooling systems.

Greg Auton, who performed most of the experiment said: “Graphene has exceptional properties; it possesses the longest carrier mean free path of any electronic material at room temperature.

“Despite this, even the most promising applications to commercialise graphene in the electronics industry do not take advantage of this property. Instead they often try to tackle the the problem that graphene has no band gap.”

Professor Song who invented the concept of the ballistic rectifier said: “The working principle of the ballistic rectifier means that it does not require any band gap. Meanwhile, it has a single-layered planar device structure which is perfect to take the advantage of the high electron-mobility to achieve an extremely high operating speed.

“Unlike conventional rectifiers or diodes, the ballistic rectifier does not have any threshold voltage either, making it perfect for energy harvest as well as microwave and infrared detection”.

The Manchester-based group is now looking to scale up the research by using large wafer-sized graphene and perform high-frequency experiments. The resulting technology can also be applied to harvesting wasted heat energy in power plants.

Making rubber more rubbery for better condoms

A May 20, 2016 news item on Nanowerk announces some research on rubber from the University of Manchester (Note: A link has been removed),

In an article published in Carbon (“Graphene and water-based elastomers thin-film composites by dip-moulding”), Dr Aravind Vijayaraghavan and Dr Maria Iliut from Manchester have shown that adding a very small amount of graphene, the world’s thinnest and strongest material, to rubber films can increase both their strength and the elasticity by up to 50%. Thin rubber films are ubiquitous in daily life, used in everything from gloves to condoms.

A May 20, 2016 University of Manchester press release (also on EurekAlert), which originated the news item, provides more detail,

In their experiments, the scientists tested two kinds of rubbery materials – natural rubber, comprised of a material called polyisoprene, and a man-made rubber called polyurethane. To these, they added graphene of different kinds, amounts and size.

In most cases, it they observed that the resulting composite material could be stretched to a greater degree and with greater force before it broke. Indeed, adding just one tenth of one percent of graphene was all it took to make the rubber 50% stronger.

Dr Vijayaraghavan, who leads the Nano-functional Materials Group, explains “A composite is a material which contains two parts, a matrix which is soft and light and a filler which is strong. Taken together, you get something which is both light and strong. This is the principle behind carbon fibre composites used in sports cars, or Kevlar composites used in body armour.

“In this case, we have made a composite of rubber, which is soft and stretchy but fragile, with graphene and the resulting material is both stronger and stretchier.”

Dr Maria Iliut, a research associate in Dr Vijayaraghavan’s group, describes how this material is produced: “We use a form of graphene called graphene oxide, which unlike graphene is stable as a dispersion in water. The rubber materials are also in a form that is stable in water, allowing us to combine them before forming thin films with a process called dip moulding.”

“The important thing here is that because these films are so thin, we need a strengthening filler which is also very thin. Fortunately, graphene is both the thinnest and strongest material we know of.”

The project emerged from a call by the Bill & Melinda Gates Foundation, to develop a more desirable condom. [my Nov. 22, 2013 post features the grant announcement and Dr. Vijayaraghavan’s research plans] According to Dr Vijayaraghavan, this composite material has tremendous implications in daily life.

He adds “Our thinking was that if we could make the rubber used in condoms stronger and stretchier, then you could use that to make even thinner condoms which would feel better without breaking.

“Similar arguments can be made for using this material to make better gloves, sportswear, medical devices and so on. We are seeing considerable industrial interest in this area and we hope more companies will want to get involved in the commercial opportunities this research could create.”

Here’s a link to and a citation for the paper,

Graphene and water-based elastomers thin-film composites by dip-moulding by Maria Iliut, Claudio Silva, Scott Herrick, Mark McGlothlin, Aravind Vijayaraghavan. Carbon doi:10.1016/j.carbon.2016.05.032 Available online 14 May 2016

This paper is open access.

 

Calming a synapse (part of a neuron) with graphene flakes

As we continue to colonize our own brains, there’s more news of graphene and neurons (see my Feb. 1, 2016 post featuring research from the same team in Italy featured in this post). A May 10, 2016 news item on ScienceDaily highlights work that could be used for epilepsy,

Innovative graphene technology to buffer the activity of synapses– this is the idea behind a recently-published study in the journal ACS Nano coordinated by the International School for Advanced Studies in Trieste (SISSA) and the University of Trieste. In particular, the study showed how effective graphene oxide flakes are at interfering with excitatory synapses, an effect that could prove useful in new treatments for diseases like epilepsy.

I guess the press release took a while to make its way through translation, here’s more from the April 10, 2016 SISSA (International School for Advanced Studies) press release (also on EurekAlert),

The laboratory of SISSA’s Laura Ballerini in collaboration with the University of Trieste, the University of Manchester and the University of Castilla -la Mancha, has discovered a new approach to modulating synapses. This methodology could be useful for treating diseases in which electrical nerve activity is altered. Ballerini and Maurizio Prato (University of Trieste) are the principal investigators of the project within the European flagship on graphene, a far-reaching 10-year international collaboration (one billion euros in funding) that studies innovative uses of the material.

Traditional treatments for neurological diseases generally include drugs that act on the brain or neurosurgery. Today however, graphene technology is showing promise for these types of applications, and is receiving increased attention from the scientific community. The method studied by Ballerini and colleagues uses “graphene nano-ribbons” (flakes) which buffer activity of synapses simply by being present.

“We administered aqueous solutions of graphene flakes to cultured neurons in ‘chronic’ exposure conditions, repeating the operation every day for a week. Analyzing functional neuronal electrical activity, we then traced the effect on synapses” says Rossana Rauti, SISSA researcher and first author of the study.

In the experiments, size of the flakes varied (10 microns or 80 nanometers) as well as the type of graphene: in one condition graphene was used, in another, graphene oxide. “The ‘buffering’ effect on synaptic activity happens only with smaller flakes of graphene oxide and not in other conditions,” says Ballerini. “The effect, in the system we tested, is selective for the excitatory synapses, while it is absent in inhibitory ones”

A Matter of Size

What is the origin of this selectivity? “We know that in principle graphene does not interact chemically with synapses in a significant way- its effect is likely due to the mere presence of synapses,” explains SISSA researcher and one of the study’s authors, Denis Scaini. “We do not yet have direct evidence, but our hypothesis is that there is a link with the sub-cellular organization of the synaptic space.”

A synapse is a contact point between one neuron and another where the nervous electrical signal “jumps” between a pre and post-synaptic unit. [emphasis mine] There is a small gap or discontinuity where the electrical signal is “translated” by a neurotransmitter and released by pre-synaptic termination into the extracellular space and reabsorbed by the postsynaptic space, to be translated again into an electrical signal. The access to this space varies depending on the type of synapses: “For the excitatory synapses, the structure’s organization allows higher exposure for the graphene flakes interaction, unlike inhibitory synapses, which are less physically accessible in this experimental model,” says Scaini.

Another clue that distance and size could be crucial in the process is found in the observation that graphene performs its function only in the oxidized form. “Normal graphene looks like a stretched and stiff sheet while graphene oxide appears crumpled, and thus possibly favoring interface with the synaptic space, ” adds Rauti.

Administering graphene flake solutions leaves the neurons alive and intact. For this reason the team thinks they could be used in biomedical applications for treating certain diseases. “We may imagine to target a drug by exploiting the apparent flakes’ selectivity for synapses, thus targeting directly the basic functional unit of neurons”concludes Ballerini.

That’s a nice description of neurons, synapses, and neurotransmitters.

Here’s a link to and a citation for the paper,

Graphene Oxide Nanosheets Reshape Synaptic Function in Cultured Brain Networks by Rossana Rauti, Neus Lozano, Veronica León, Denis Scaini†, Mattia Musto, Ilaria Rago, Francesco P. Ulloa Severino, Alessandra Fabbro, Loredana Casalis, Ester Vázquez, Kostas Kostarelos, Maurizio Prato, and Laura Ballerini. ACS Nano, 2016, 10 (4), pp 4459–4471
DOI: 10.1021/acsnano.6b00130 Publication Date (Web): March 31, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

With over 150 partners from over 20 countries, the European Union’s Graphene Flagship research initiative unveils its work package devoted to biomedical technologies

An April 11, 2016 news item on Nanowerk announces the Graphene Flagship’s latest work package,

With a budget of €1 billion, the Graphene Flagship represents a new form of joint, coordinated research on an unprecedented scale, forming Europe’s biggest ever research initiative. It was launched in 2013 to bring together academic and industrial researchers to take graphene from the realm of academic laboratories into European society in the timeframe of 10 years. The initiative currently involves over 150 partners from more than 20 European countries. The Graphene Flagship, coordinated by Chalmers University of Technology (Sweden), is implemented around 15 scientific Work Packages on specific science and technology topics, such as fundamental science, materials, health and environment, energy, sensors, flexible electronics and spintronics.

Today [April 11, 2016], the Graphene Flagship announced in Barcelona the creation of a new Work Package devoted to Biomedical Technologies, one emerging application area for graphene and other 2D materials. This initiative is led by Professor Kostas Kostarelos, from the University of Manchester (United Kingdom), and ICREA Professor Jose Antonio Garrido, from the Catalan Institute of Nanoscience and Nanotechnology (ICN2, Spain). The Kick-off event, held in the Casa Convalescència of the Universitat Autònoma de Barcelona (UAB), is co-organised by ICN2 (ICREA Prof Jose Antonio Garrido), Centro Nacional de Microelectrónica (CNM-IMB-CSIC, CIBER-BBN; CSIC Tenured Scientist Dr Rosa Villa), and Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS; ICREA Prof Mavi Sánchez-Vives).

An April 11, 2016 ICN2 press release, which originated the news item, provides more detail about the Biomedical Technologies work package and other work packages,

The new Work Package will focus on the development of implants based on graphene and 2D-materials that have therapeutic functionalities for specific clinical outcomes, in disciplines such as neurology, ophthalmology and surgery. It will include research in three main areas: Materials Engineering; Implant Technology & Engineering; and Functionality and Therapeutic Efficacy. The objective is to explore novel implants with therapeutic capacity that will be further developed in the next phases of the Graphene Flagship.

The Materials Engineering area will be devoted to the production, characterisation, chemical modification and optimisation of graphene materials that will be adopted for the design of implants and therapeutic element technologies. Its results will be applied by the Implant Technology and Engineering area on the design of implant technologies. Several teams will work in parallel on retinal, cortical, and deep brain implants, as well as devices to be applied in the periphery nerve system. Finally, The Functionality and Therapeutic Efficacy area activities will centre on development of devices that, in addition to interfacing the nerve system for recording and stimulation of electrical activity, also have therapeutic functionality.

Stimulation therapies will focus on the adoption of graphene materials in implants with stimulation capabilities in Parkinson’s, blindness and epilepsy disease models. On the other hand, biological therapies will focus on the development of graphene materials as transport devices of biological molecules (nucleic acids, protein fragments, peptides) for modulation of neurophysiological processes. Both approaches involve a transversal innovation environment that brings together the efforts of different Work Packages within the Graphene Flagship.

A leading role for Barcelona in Graphene and 2D-Materials

The kick-off meeting of the new Graphene Flagship Work Package takes place in Barcelona because of the strong involvement of local institutions and the high international profile of Catalonia in 2D-materials and biomedical research. Institutions such as the Catalan Institute of Nanoscience and Nanotechnology (ICN2) develop frontier research in a supportive environment which attracts talented researchers from abroad, such as ICREA Research Prof Jose Antonio Garrido, Group Leader of the ICN2 Advanced Electronic Materials and Devices Group and now also Deputy Leader of the Biomedical Technologies Work Package. Until summer 2015 he was leading a research group at the Technische Universität München (Germany).

Further Graphene Flagship events in Barcelona are planned; in May 2016 ICN2 will also host a meeting of the Spintronics Work Package. ICREA Prof Stephan Roche, Group Leader of the ICN2 Theoretical and Computational Nanoscience Group, is the deputy leader of this Work Package led by Prof Bart van Wees, from the University of Groningen (The Netherlands). Another Work Package, on optoelectronics, is led by Prof Frank Koppens from the Institute of Photonic Sciences (ICFO, Spain), with Prof Andrea Ferrari from the University of Cambridge (United Kingdom) as deputy. Thus a number of prominent research institutes in Barcelona are deeply involved in the coordination of this European research initiative.

Kostas Kostarelos, the leader of the Biomedical Technologies Graphene Flagship work package, has been mentioned here before in the context of his blog posts for The Guardian science blog network (see my Aug. 7, 2014 post for a link to his post on metaphors used in medicine).

Tempest in a teapot or a sign of things to come? UK’s National Graphene Institute kerfuffle

A scandal-in-the-offing, intellectual property, miffed academics, a chortling businessman, graphene, and much more make this a fascinating story.

Before launching into the main attractions, those unfamiliar with the UK graphene effort might find this background informal useful. Graphene, was first isolated at the University of Manchester in 2004 by scientists Andre Geim* and Konstantin Novoselov, Russian immigrants, both of whom have since become Nobel laureates and knights of the realm. The excitement in the UK and elsewhere is due to graphene’s extraordinary properties which could lead to transparent electronics, foldable/bendable electronics, better implants, efficient and inexpensive (they hope) water filters, and more. The UK government has invested a lot of money in graphene as has the European Union (1B Euros in the Graphene Flagship) in the hope that huge economic benefits will be reaped.

Dexter Johnson’s March 15, 2016 posting on his Nanoclast blog (on the IEEE [Institute for Electrical and Electronics Engineers] website) provides details about the situation (Note: Links have been removed),

A technology that, a year ago, was being lauded as the “first commercially viable consumer product” using graphene now appears to be caught up in an imbroglio over who owns its intellectual property rights. The resulting controversy has left the research institute behind the technology in a bit of a public relations quagmire.

The venerable UK publication The Sunday Times reported this week on what appeared to be a mutiny occurring at the National Graphene Institute (NGI) located at the University of Manchester. Researchers at the NGI had reportedly stayed away from working at the institute’s gleaming new $71 million research facility over fears that their research was going to end up in the hands of foreign companies, in particular a Taiwan-based company called BGT Materials.

The “first commercially viable consumer product” noted in Dexter’s posting was a graphene-based lightbulb which was announced by the NGI to much loud crowing in March 2015 (see my March 30, 2015 posting). The company producing the lightbulb was announced as “… Graphene Lighting PLC is a spin-out based on a strategic partnership with the National Graphene Institute (NGI) at The University of Manchester to create graphene applications.” There was no mention of BGT.

Dexter describes the situation from the BGT perspective (from his March 15, 2016 posting), Note: Links have been removed,

… BGT did not demur when asked by  the Times whether it owned the technology. In fact, Chung Ping Lai, BGT’s CEO, claimed it was his company that had invented the technology for the light bulb and not the NGI. The Times report further stated that Lai controls all the key patents and claims to be delighted with his joint venture with the university. “I believe in luck and I have had luck in Manchester,” Lai told the Times.

With companies outside the UK holding majority stakes in the companies spun out of the NGI—allowing them to claim ownership of the technologies developed at the institute—one is left to wonder what was the purpose of the £50 million (US $79 million) earmarked for graphene research in the UK more than four years ago? Was it to develop a local economy based around graphene—a “Graphene Valley”, if you will? Or was it to prop up the local construction industry through the building of shiny new buildings that reportedly few people occupy? That’s the charge leveled by Andre Geim, Nobel laureate for his discovery of graphene, and NGI’s shining star. Geim reportedly described the new NGI building as: “Money put in the British building industry rather than science.”

Dexter ends his March 15, 2016 posting with an observation  that will seem familiar to Canadians,

Now, it seems the government’s eagerness to invest in graphene research—or at least, the facilities for conducting that research—might have ended up bringing it to the same place as its previous lack of investment: the science is done in the UK and the exploitation of the technology is done elsewhere.

The March 13, 2016 Sunday Times article [ETA on April 3, 2016: This article is now behind a paywall] by Tom Harper, Jon Ungoed-Thomas and Michael Sheridan, which seems to be the source of Dexter’s posting, takes a more partisan approach,

ACADEMICS are boycotting a top research facility after a company linked to China was given access to lucrative confidential material from one of Britain’s greatest scientific breakthroughs.

Some scientists at Manchester University working on graphene, a wonder substance 200 times stronger than steel, refuse to work at the new £61m national institution, set up to find ways to exploit the material, amid concerns over a deal struck between senior university management and BGT Materials.

The academics are concerned that the National Graphene Institute (NGI), which was opened last year by George Osborne, the chancellor, and forms one of the key planks of his “northern powerhouse” industrial strategy, does not have the necessary safeguards to protect their confidential research, which could revolutionise the electronics, energy, health and building industries.

BGT, which is controlled by a Taiwanese businessman, subsequently agreed to work with a Chinese manufacturing company and university to develop similar graphene technology.

BGT says its work in Manchester has been successful and it is “offensive” and “untrue” to suggest that it would unfairly use intellectual property. The university say there is no evidence “whatsoever” of unfair use of confidential information. Manchester says it is understandable that some scientists are cautious about the collaborative environment of the new institute. But one senior academic said the arrangement with BGT had caused the university’s graphene research to descend into “complete anarchy”.

The academic said: “The NGI is a national facility, and why should we use it for a company, which is not even an English [owned] company? How much [intellectual property] is staying in England and how much is going to Taiwan?”

The row highlights concerns that the UK has dawdled in developing one of its greatest discoveries. Nearly 50% of ­graphene-related patents have been filed in China, and just 1% in Britain.

Manchester signed a £5m “research collaboration agreement” with BGT Materials in October 2013. Although the company is controlled by a Taiwanese businessman, Chung-ping Lai, the university does have a 17.5% shareholding.

Manchester claimed that the commercial deal would “attract a significant number of jobs to the city” and “benefit the UK economy”.

However, an investigation by The Sunday Times has established:

Only four jobs have been created as a result of the deal and BGT has not paid the full £5m due under the agreement after two projects were cancelled.

Pictures sent to The Sunday Times by a source at the university last month show that the offices at the NGI [National Graphene Institute], which can accommodate 120 staff, were deserted.

British-based businessmen working with graphene have also told The Sunday Times of their concerns about the institute’s information security. Tim Harper, a Manchester-based graphene entrepreneur, said: “We looked at locating there [at the NGI] but we take intellectual property extremely seriously and it is a problem locating in such a facility.

“If you don’t have control over your computer systems or the keys to your lab, then you’ve got a problem.”

I recommend reading Dexter’s post and the Sunday Times article as they provide some compelling insight into the UK situation vis à vis nanotechnology, science, and innovation.

*’Gheim’ corrected to ‘Geim’ on March 30, 2016.

Graphene like honey

Two teams have published results in Science magazine showing that graphene can flow like a liquid. The UK-Italian team has likened the movement to honey while the US team likened it to water (Feb. 18, 2016 posting). Here’s more about the honey from a Feb. 12, 2016 news item on Nanowerk (Note: A link has been removed),

Electrons which act like slow-pouring honey have been observed for the first time in graphene, prompting a new approach to fundamental physics.

Electrons are known to move through metals like bullets being reflected only by imperfections, but in graphene they move like in a very viscous liquid, University of Manchester researchers have found.

The possibility of a highly viscous flow of electrons in metals was predicted several decades ago but despite numerous efforts never observed, until now as reported in the journal Science (“Negative local resistance caused by viscous electron backflow in graphene”).

The observation and study of this effect allows better understanding of the counterintuitive behaviour of interacting particles, where the human knowledge and developed mathematical techniques are lacking.

A Feb. 11, 2016 University of Manchester press release, which originated the news item, offers more technical detail,

One-atom thick material graphene, first explored a decade ago by a team at The University of Manchester, is renowned for its many superlative properties and, especially, exceptionally high electrical conductivity.

It is widely believed that electrons in graphene can move ‘ballistically’, like bullets or billiard balls scattering only at graphene boundaries or other imperfections.

The reality is not quite so simple, as found by a Manchester group led by Sir Andre Geim in collaboration with Italian researchers led by Prof Marco Polini.

They observed that the electric current in graphene did not flow along the applied electric field, as in other materials, but travelled backwards forming whirlpools where circular currents appeared.Such behaviour is familiar for conventional liquids such as water which makes whirlpools when flowing around obstacles, for example, in rivers.

The scientists measured the viscosity of this strange new liquid in graphene, which consists not of water molecules but electrons. To the researchers surprise, the electron fluid can be 100 times more viscous than honey, even at room temperature.

The scientific breakthrough is important for understanding of how materials work at increasing smaller sizes required by the semiconducting industry because such whirlpools are more likely to appear at micro and nanoscale.

The observation also questions our current understanding of the physics of highly conductive metals, especially graphene itself.

The simultaneous existence of such seemingly incompatible properties, with electrons behaving like bullets and a liquid in the same material prompts a fundamental rethinking about our understanding of materials properties.

Professor Polini commented: “Giving decades long efforts to find even minor signs of a viscous flow in metals, we were flabbergasted that graphene exhibited not just some small blip on an experimental curve but the clear qualitative effect, a large backflow of electric current.”

Sir Andre Geim, who received a Nobel Prize for graphene, added: “Graphene cannot stop amazing us. Now we need to think long and hard how to connect such contradictory behaviour as ballistic motion of electrons, which is undoubtedly seen in graphene, with this new quantum weirdness arising from their collective motion. A strong adjustment of our understanding of the physics is due.”

Here’s a link to and a citation for the paper,

Negative local resistance caused by viscous electron backflow in graphene by D. A. Bandurin, I. Torre, R. Krishna Kumar, M. Ben Shalom, A. Tomadin, A. Principi, G. H. Auton, E. Khestanova, K. S. Novoselov, I. V. Grigorieva, L. A. Ponomarenko, A. K. Geim, M. Polini. Science  11 Feb 2016: pp. DOI: 10.1126/science.aad0201

This paper is behind a paywall.

Here’s an image supplied by the University of Manchester illustrating the discovery,

Courtesy University of Manchester

Courtesy University of Manchester

Wearable tech for Christmas 2015 and into 2016

This is a roundup post of four items to cross my path this morning (Dec. 17, 2015), all of them concerned with wearable technology.

The first, a Dec. 16, 2015 news item on phys.org, is a fluffy little piece concerning the imminent arrival of a new generation of wearable technology,

It’s not every day that there’s a news story about socks. But in November [2015], a pair won the Best New Wearable Technology Device Award at a Silicon Valley conference. The smart socks, which track foot landings and cadence, are at the forefront of a new generation of wearable electronics, according to an article in Chemical & Engineering News (C&EN), the weekly newsmagazine of the American Chemical Society [ACS].

That news item was originated by a Dec. 16, 2015 ACS news release on EurekAlert which adds this,

Marc S. Reisch, a senior correspondent at C&EN, notes that stiff wristbands like the popular FitBit that measure heart rate and the number of steps people take have become common. But the long-touted technology needed to create more flexible monitoring devices has finally reached the market. Developers have successfully figured out how to incorporate stretchable wiring and conductive inks in clothing fabric, program them to transmit data wirelessly and withstand washing.

In addition to smart socks, fitness shirts and shoe insoles are on the market already or are nearly there. Although athletes are among the first to gain from the technology, the less fitness-oriented among us could also benefit. One fabric concept product — designed not for covering humans but a car steering-wheel — could sense driver alertness and make roads safer.

Reisch’s Dec. 7, 2015 article (C&EN vol. 93, issue 48, pp. 28-90) provides more detailed information and market information such as this,

Materials suppliers, component makers, and apparel developers gathered at a printed-electronics conference in Santa Clara, Calif., within a short drive of tech giants such as Google and Apple, to compare notes on embedding electronics into the routines of daily life. A notable theme was the effort to stealthily [emphasis mine] place sensors on exercise shirts, socks, and shoe soles so that athletes and fitness buffs can wirelessly track their workouts and doctors can monitor the health of their patients.

“Wearable technology is becoming more wearable,” said Raghu Das, chief executive officer of IDTechEx [emphasis mine], the consulting firm that organized the conference. By that he meant the trend is toward thinner and more flexible devices that include not just wrist-worn fitness bands but also textiles printed with stretchable wiring and electronic sensors, thanks to advances in conductive inks.

Interesting use of the word ‘stealthy’, which often suggests something sneaky as opposed to merely secretive. I imagine what’s being suggested is that the technology will not impose itself on the user (i.e., you won’t have to learn how to use it as you did with phones and computers).

Leading into my second item, IDC (International Data Corporation), not to be confused with IDTechEx, is mentioned in a Dec. 17, 2015 news item about wearable technology markets on phys.org,

The global market for wearable technology is seeing a surge, led by watches, smart clothing and other connected gadgets, a research report said Thursday [Dec. 16, 2015].

IDC said its forecast showed the worldwide wearable device market will reach a total of 111.1 million units in 2016, up 44.4 percent from this year.

By 2019, IDC sees some 214.6 million units, or a growth rate averaging 28 percent.

A Dec. 17, 2015 IDC press release, which originated the news item, provides more details about the market forecast,

“The most common type of wearables today are fairly basic, like fitness trackers, but over the next few years we expect a proliferation of form factors and device types,” said Jitesh Ubrani , Senior Research Analyst for IDC Mobile Device Trackers. “Smarter clothing, eyewear, and even hearables (ear-worn devices) are all in their early stages of mass adoption. Though at present these may not be significantly smarter than their analog counterparts, the next generation of wearables are on track to offer vastly improved experiences and perhaps even augment human abilities.”

One of the most popular types of wearables will be smartwatches, reaching a total of 34.3 million units shipped in 2016, up from the 21.3 million units expected to ship in 2015. By 2019, the final year of the forecast, total shipments will reach 88.3 million units, resulting in a five-year CAGR of 42.8%.

“In a short amount of time, smartwatches have evolved from being extensions of the smartphone to wearable computers capable of communications, notifications, applications, and numerous other functionalities,” noted Ramon Llamas , Research Manager for IDC’s Wearables team. “The smartwatch we have today will look nothing like the smartwatch we will see in the future. Cellular connectivity, health sensors, not to mention the explosive third-party application market all stand to change the game and will raise both the appeal and value of the market going forward.

“Smartwatch platforms will lead the evolution,” added Llamas. “As the brains of the smartwatch, platforms manage all the tasks and processes, not the least of which are interacting with the user, running all of the applications, and connecting with the smartphone. Once that third element is replaced with cellular connectivity, the first two elements will take on greater roles to make sense of all the data and connections.”

Top Five Smartwatch Platform Highlights

Apple’s watchOS will lead the smartwatch market throughout our forecast, with a loyal fanbase of Apple product owners and a rapidly growing application selection, including both native apps and Watch-designed apps. Very quickly, watchOS has become the measuring stick against which other smartwatches and platforms are compared. While there is much room for improvement and additional features, there is enough momentum to keep it ahead of the rest of the market.

Android/Android Wear will be a distant second behind watchOS even as its vendor list grows to include technology companies (ASUS, Huawei, LG, Motorola, and Sony) and traditional watchmakers (Fossil and Tag Heuer). The user experience on Android Wear devices has been largely the same from one device to the next, leaving little room for OEMs to develop further and users left to select solely on price and smartwatch design.

Smartwatch pioneer Pebble will cede market share to AndroidWear and watchOS but will not disappear altogether. Its simple user interface and devices make for an easy-to-understand use case, and its price point relative to other platforms makes Pebble one of the most affordable smartwatches on the market.

Samsung’s Tizen stands to be the dark horse of the smartwatch market and poses a threat to Android Wear, including compatibility with most flagship Android smartphones and an application selection rivaling Android Wear. Moreover, with Samsung, Tizen has benefited from technology developments including a QWERTY keyboard on a smartwatch screen, cellular connectivity, and new user interfaces. It’s a combination that helps Tizen stand out, but not enough to keep up with AndroidWear and watchOS.

There will be a small, but nonetheless significant market for smart wristwear running on a Real-Time Operating System (RTOS), which is capable of running third-party applications, but not on any of these listed platforms. These tend to be proprietary operating systems and OEMs will use them when they want to champion their own devices. These will help within specific markets or devices, but will not overtake the majority of the market.

The company has provided a table with five-year CAGR (compound annual growth rate) growth estimates, which can be found with the Dec. 17, 2015 IDC press release.

Disclaimer: I am not endorsing IDC’s claims regarding the market for wearable technology.

For the third and fourth items, it’s back to the science. A Dec. 17, 2015 news item on Nanowerk, describes, in general terms, some recent wearable technology research at the University of Manchester (UK), Note: A link has been removed),

Cheap, flexible, wireless graphene communication devices such as mobile phones and healthcare monitors can be directly printed into clothing and even skin, University of Manchester academics have demonstrated.

In a breakthrough paper in Scientific Reports (“Highly Flexible and Conductive Printed Graphene for Wireless Wearable Communications Applications”), the researchers show how graphene could be crucial to wearable electronic applications because it is highly-conductive and ultra-flexible.

The research could pave the way for smart, battery-free healthcare and fitness monitoring, phones, internet-ready devices and chargers to be incorporated into clothing and ‘smart skin’ applications – printed graphene sensors integrated with other 2D materials stuck onto a patient’s skin to monitor temperature, strain and moisture levels.

Detail is provided in a Dec. 17, 2015 University of Manchester press release, which originated the news item, (Note: Links have been removed),

Examples of communication devices include:

• In a hospital, a patient wears a printed graphene RFID tag on his or her arm. The tag, integrated with other 2D materials, can sense the patient’s body temperature and heartbeat and sends them back to the reader. The medical staff can monitor the patient’s conditions wirelessly, greatly simplifying the patient’s care.

• In a care home, battery-free printed graphene sensors can be printed on elderly peoples’ clothes. These sensors could detect and collect elderly people’s health conditions and send them back to the monitoring access points when they are interrogated, enabling remote healthcare and improving quality of life.

Existing materials used in wearable devices are either too expensive, such as silver nanoparticles, or not adequately conductive to have an effect, such as conductive polymers.

Graphene, the world’s thinnest, strongest and most conductive material, is perfect for the wearables market because of its broad range of superlative qualities. Graphene conductive ink can be cheaply mass produced and printed onto various materials, including clothing and paper.

“Sir Kostya Novoselov

To see evidence that cheap, scalable wearable communication devices are on the horizon is excellent news for graphene commercial applications.

Sir Kostya Novoselov (tweet)„

The researchers, led by Dr Zhirun Hu, printed graphene to construct transmission lines and antennas and experimented with these in communication devices, such as mobile and Wifi connectivity.

Using a mannequin, they attached graphene-enabled antennas on each arm. The devices were able to ‘talk’ to each other, effectively creating an on-body communications system.

The results proved that graphene enabled components have the required quality and functionality for wireless wearable devices.

Dr Hu, from the School of Electrical and Electronic Engineering, said: “This is a significant step forward – we can expect to see a truly all graphene enabled wireless wearable communications system in the near future.

“The potential applications for this research are huge – whether it be for health monitoring, mobile communications or applications attached to skin for monitoring or messaging.

“This work demonstrates that this revolutionary scientific material is bringing a real change into our daily lives.”

Co-author Sir Kostya Novoselov, who with his colleague Sir Andre Geim first isolated graphene at the University in 2004, added: “Research into graphene has thrown up significant potential applications, but to see evidence that cheap, scalable wearable communication devices are on the horizon is excellent news for graphene commercial applications.”

Here’s a link to and a citation for the paper,

Highly Flexible and Conductive Printed Graphene for Wireless Wearable Communications Applications by Xianjun Huang, Ting Leng, Mengjian Zhu, Xiao Zhang, JiaCing Chen, KuoHsin Chang, Mohammed Aqeeli, Andre K. Geim, Kostya S. Novoselov, & Zhirun Hu. Scientific Reports 5, Article number: 18298 (2015) doi:10.1038/srep18298 Published online: 17 December 2015

This is an open access paper.

The next and final item concerns supercapacitors for wearable tech, which makes it slightly different from the other items and is why, despite the date, this is the final item. The research comes from Case Western Research University (CWRU; US) according to a Dec. 16, 2015 news item on Nanowerk (Note: A link has been removed),

Wearable power sources for wearable electronics are limited by the size of garments.

With that in mind, researchers at Case Western Reserve University have developed flexible wire-shaped microsupercapacitors that can be woven into a jacket, shirt or dress (Energy Storage Materials, “Flexible and wearable wire-shaped microsupercapacitors based on highly aligned titania and carbon nanotubes”).

A Dec. 16, 2015 CWRU news release (on EurekAlert), which originated the news item, provides more detail about a device that would make wearable tech more wearable (after all, you don’t want to recharge your clothes the same way you do your phone and other mobile devices),

By their design or by connecting the capacitors in series or parallel, the devices can be tailored to match the charge storage and delivery needs of electronics donned.

While there’s been progress in development of those electronics–body cameras, smart glasses, sensors that monitor health, activity trackers and more–one challenge remaining is providing less obtrusive and cumbersome power sources.

“The area of clothing is fixed, so to generate the power density needed in a small area, we grew radially-aligned titanium oxide nanotubes on a titanium wire used as the main electrode,” said Liming Dai, the Kent Hale Smith Professor of Macromolecular Science and Engineering. “By increasing the surface area of the electrode, you increase the capacitance.”

Dai and Tao Chen, a postdoctoral fellow in molecular science and engineering at Case Western Reserve, published their research on the microsupercapacitor in the journal Energy Storage Materials this week. The study builds on earlier carbon-based supercapacitors.

A capacitor is cousin to the battery, but offers the advantage of charging and releasing energy much faster.

How it works

In this new supercapacitor, the modified titanium wire is coated with a solid electrolyte made of polyvinyl alcohol and phosphoric acid. The wire is then wrapped with either yarn or a sheet made of aligned carbon nanotubes, which serves as the second electrode. The titanium oxide nanotubes, which are semiconducting, separate the two active portions of the electrodes, preventing a short circuit.

In testing, capacitance–the capability to store charge–increased from 0.57 to 0.9 to 1.04 milliFarads per micrometer as the strands of carbon nanotube yarn were increased from 1 to 2 to 3.

When wrapped with a sheet of carbon nanotubes, which increases the effective area of electrode, the microsupercapactitor stored 1.84 milliFarads per micrometer. Energy density was 0.16 x 10-3 milliwatt-hours per cubic centimeter and power density .01 milliwatt per cubic centimeter.

Whether wrapped with yarn or a sheet, the microsupercapacitor retained at least 80 percent of its capacitance after 1,000 charge-discharge cycles. To match various specific power needs of wearable devices, the wire-shaped capacitors can be connected in series or parallel to raise voltage or current, the researchers say.

When bent up to 180 degrees hundreds of times, the capacitors showed no loss of performance. Those wrapped in sheets showed more mechanical strength.

“They’re very flexible, so they can be integrated into fabric or textile materials,” Dai said. “They can be a wearable, flexible power source for wearable electronics and also for self-powered biosensors or other biomedical devices, particularly for applications inside the body.” [emphasis mine]

Dai ‘s lab is in the process of weaving the wire-like capacitors into fabric and integrating them with a wearable device.

So one day we may be carrying supercapacitors in our bodies? I’m not sure how I feel about that goal. In any event, here’s a link and a citation for the paper,

Flexible and wearable wire-shaped microsupercapacitors based on highly aligned titania and carbon nanotubes by Tao Chen, Liming Dai. Energy Storage Materials Volume 2, January 2016, Pages 21–26 doi:10.1016/j.ensm.2015.11.004

This paper appears to be open access.

Bicycle tyres, graphene, and a cycling revolution

Despite the wording in an Oct. 29, 2015 news item on Azonano you are not being invited to visit a factory (Note: A link has been removed),

Vittoria and Directa Plus host a unique opportunity to get an inside view in the factory where pristine Graphene is produced.

Not only will a select audience get a first-hand experience in seeing the blocking patent-protected end-to-end manufacturing process, they are exclusively selected to share the story of a material that is making it possible for Vittoria to lead a cycling revolution.

You are being invited to view this video,

An Oct. 26, 2015 Vittoria press announcement, which originated the news item, waxes eloquent about its graphene-producing partner, Directa Plus, and its new ‘graphene tyres’,

Directa Plus started its journey in 2005 [emphasis mine], in a time when a number of companies joined a race in blocking patents that would give them a huge head start in the market for recently isolated material Graphene.

With a philosophy of environmental neutrality, Directa Plus chose a unique clean direction that eventually gave them the edge in the bulk manufacturing of pristine Graphene nanoplatelets. At exactly the right time for both companies, the chairmen met each other at a function. When the application of Graphene became a logical next step, Vittoria offered the challenge to try and make this material work for cycling wheels and tires.

With continuous and significant investments, Vittoria is always seeking the cutting edge in cycling performance products through innovation. Through the Directa Plus-Vittoria partnership, both companies have unlocked a whole new level.

Unique Properties of Revolutionary Material Graphene

The guided tour immediately makes clear that the state of the art facilities of Directa Plus set the bar for next generation manufacturing. In a very white and clean environment, every step in the manufacturing process takes place in a very compact area and provide a different product with a dedicated purpose.

The company is extremely proud of the achievement to have zero impact on the environment. Both Vittoria and Directa Plus share an intense focus on quality, safety, health and environmental protection and this is clearly visible throughout the factory tour. After a close look at the overall production plant, the super-expansion process, the exfoliation and the output of 30 tons of Graphene end products in various shapes and forms, unique real-life applications are demonstrated.

One of the Graphene Plus’ products is a super-performant adsorbent towards hydrocarbons for water and soil purification. As demonstrated in the presence of the attendees, a highly polluted water tank is filtered with Graphene resulting in potable water.

Safety requirements prevent a live fireresistance demo, but Directa Plus shows a video that demonstrates the ability to treat a material with Graphene to achieve a completely non-flammable end result. Additional practical applications were illustrated through Vittoria best practices: commercial products, available for sale worldwide.

The Vittoria Best Practices: Carbon, Rubber, Special Applications

Vittoria introduced Graphene-enhanced carbon wheels for high performance road and MTB wheels in 2014. In close collaboration with Directa Plus, Vittoria will also soon introduce full carbon clinchers that can be mounted as a tubeless system.

In September this year, Vittoria announced a massive revision of its product range that includes the fastest road tire ever measured, as well as the best uncompromised competitive products for road racing in the market.

Furthermore, a highly innovative combination of Graphene and Vittoria’s 4C (4 compound) technology has enabled the introduction of more strength, more grip and greater durability for performance MTB tires. Vittoria even extended its newfound Graphene expertise to deliver fast-rolling and durable city tires that bring the greatly enhanced rubber properties to all consumers.

Perhaps the most remarkable achievement of all is the combined expertise of Directa Plus for
Graphene and the tire construction capabilities of Vittoria’s manufacturing facility Lion Tyres, dedicated to the special application of electric mountain bike tires. Again leveraging the 4C technology and specific Graphene-enhanced compounds, Vittoria has now developed 2 tires that can handle the electric engine torque as well as the roughest of terrains seemingly without effort.

No Compromise.

Effectively, the introduction of Graphene allows for natural material barriers of rubber to be removed, which means that there is no longer the need for compromises between speed, grip, durability and puncture resistance. All these features are now reaching their maximum possibilities.

Full carbon wheels will also reach new heights. With the application of Graphene, the natural properties of carbon are pushed way beyond natural limits in lateral stiffness, impact strength, weight reduction and heat dissipation, just to highlight a few key areas. The features of carbon are now extended to withstand the high pressure of tubeless mounted tires even under heavy braking circumstances without compromise.

In short, this is why Vittoria has started a cycling revolution.

Directa Plus started its graphene journey very early when you consider that the material was not successfully isolated until 2004 by Andre Geim and Konstantin (Kostya) Novosolov at the University of Manchester.