Category Archives: electronics

‘Genius’ grant (MacArthur Fellowship) for reseacher Mark Hersam and his work on carbon nanotubes and the next generation of electronics

It took a few minutes to figure out why Mark Hersam, professor at Northwestern University (Chicago, Illinois, US) is being featured in an Oct. 21, 2014 news item on Nanowerk,

One of the longstanding problems of working with nanomaterials–substances at the molecular and atomic scale–is controlling their size. When their size changes, their properties also change. This suggests that uniform control over size is critical in order to use them reliably as components in electronics.

Put another way, “if you don’t control size, you will have inhomogeneity in performance,” says Mark Hersam. “You don’t want some of your cell phones to work, and others not.”

Hersam, a professor of materials science engineering, chemistry and medicine at Northwestern University, has developed a method to separate nanomaterials by size, therefore providing a consistency in properties otherwise not available. Moreover, the solution came straight from the life sciences–biochemistry, in fact.

The technique, known as density gradient ultracentrifugation, is a decades-old process used to separate biomolecules. The National Science Foundation (NSF)-funded scientist theorized correctly that he could adapt it to separate carbon nanotubes, rolled sheets of graphene (a single atomic layer of hexagonally bonded carbon atoms), long recognized for their potential applications in computers and tablets, smart phones and other portable devices, photovoltaics, batteries and bioimaging.

The technique has proved so successful that Hersam and his team now hold two dozen pending or issued patents, and in 2007 established their own company, NanoIntegris, jump-started with a $150,000 NSF small business grant. The company has been able to scale up production by 10,000-fold, and currently has 700 customers in 40 countries.
“We now have the capacity to produce ten times the worldwide demand for this material,” Hersam says.

NSF supports Hersam with a $640,000 individual investigator grant awarded in 2010 for five years. Also, he directs Northwestern’s Materials Research Science and Engineering Center (MRSEC), which NSF funds, including support for approximately 30 faculty members/researchers.

Hersam also is a recent recipient of one of this year’s prestigious MacArthur fellowships, a $625,000 no-strings-attached award, popularly known as a “genius” grant. [emphases mine] These go to talented individuals who have shown extraordinary originality and dedication in their fields, and are meant to encourage beneficiaries to freely explore their interests without fear of risk-taking.

An Oct. 20, 2014 US National Science Foundation Discoveries article by Marlene Cimons, which originated the news item, describes Hersam’s research and his hopes for it in more detail,

The carbon nanotubes separation process, which Hersam developed, begins with a centrifuge tube. Into that, “we load a water based solution and introduce an additive which allows us to tune the buoyant density of the solution itself,” he explains.

“What we create is a gradient in the buoyant density of the aqueous solution, with low density at the top and high density at the bottom,” he continues. “We then load the carbon nanotubes and put it into the centrifuge, which drives the nanotubes through the gradient. The nanotubes move through the gradient until their density matches that of the gradient. The result is that the nanotubes form separated bands in the centrifuge tube by density. Since the density of the nanotube is a function of its diameter, this method allows separation by diameter.”

One property that distinguishes these materials from traditional semiconductors like silicon is that they are mechanically flexible. “Carbon nanotubes are highly resilient,” Hersam says. “That allows us to integrate electronics on flexible substrates, like clothing, shoes, and wrist bands for real time monitoring of biomedical diagnostics and athletic performance. These materials have the right combination of properties to realize wearable electronics.”

He and his colleagues also are working on energy technologies, such as solar cells and batteries “that can improve efficiency and reduce the cost of solar cells, and increase the capacity and reduce the charging time of batteries,” he says. “The resulting batteries and solar cells are also mechanically flexible, and thus can be integrated with flexible electronics.”

They likely even will prove waterproof. “It turns out that carbon nanomaterials are hydrophobic, so water will roll right off of them,” he says.

A Sept. 17, 2014 Northwestern University news release congratulates Hersam on his award while describing his response to the news and providing more information about his work as a researcher and teacher (Note: Links have been removed),

The phone call from the John D. and Catherine T. MacArthur Foundation delivering the very good news was so out of the blue that Hersam initially thought it was a joke.

“Then I went into shock, and, I think, to some extent I remain in shock,” said Hersam, who received the call in his Cook Hall office. “As time has gone on, I’ve appreciated, of course, that it’s a great honor and, more importantly, a great opportunity.”

A dedicated and popular teacher, Hersam is the Bette and Neison Harris Chair in Teaching Excellence and professor of materials science and engineering at the McCormick School of Engineering and Applied Science.

“There are very few awards that provide unrestricted resources, and this one does. No strings attached,” he said. “That’s a great opportunity for a researcher — to have that level of freedom.”

Hersam is one of 21 new MacArthur Fellows recognized today (Sept. 17) by the MacArthur Foundation for “extraordinary originality and dedication in their creative pursuits and a marked capacity for self-direction.”

“I am very grateful and thankful to the MacArthur Foundation, to current and previous members of my research group and to my colleagues and collaborators over the years,” Hersam said. “Scientific research is a team effort.”

Hersam views his principal job as that of an educator — a role in which he can have more impact on unsolved problems by harnessing the minds of hundreds of young scientists and engineers.

“I love to teach in the classroom, but I also believe that scientific research is a vehicle for teaching,” Hersam said. “Research exposes students to difficult unsolved problems, forcing them to be creative. I want them to come up with truly new ideas, not just regurgitate established concepts.”

Hersam, who joined Northwestern in 2000, also is professor of chemistry in the Weinberg College of Arts and Sciences, professor of medicine at the Northwestern University Feinberg School of Medicine and director of Northwestern’s Materials Research Center.

Taking an interdisciplinary approach that draws on techniques from materials science, physics, engineering and chemistry, Hersam has established himself as a leading experimentalist in the area of hybrid organic-inorganic materials, with a focus on the study of the electrical and optical properties of carbon and related nanomaterials.

Hersam and his research lab have been working primarily with carbon nanotubes and graphene, but the support of the MacArthur award will allow the lab to diversify its materials set to other elements in the periodic table.

Earlier this year Hersam testified before U.S. Congress to push for “coordinated, predictable and sustained federal funding” for nanotechnology research and development.

The MacArthur Foundation’s website hosts a video on its ‘Mark Hersam’ webpage,

Interestingly, Hersam, in the video, describes a carbon nanotube as a rolled up sheet of graphene (it’s also described that way on the Foundation’s ‘Hersam’ webpage),

Graphene, a single atomic layer of hexagonally bonded carbon atoms, and carbon nanotubes, rolled sheets of graphene in single or multiple layers, have long been recognized for their potential applications in electronics, photovoltaics, batteries, and bioimaging.

It’s a good way of describing carbon nanotubes but the odd thing is that carbon nanotubes were discovered in 1991 (Timeline of carbon nanotubes entry on Wikipedia and in The History of Carbon Nanotubes on nanogloss.com) before graphene was first isolated in 2004 (my Oct. 7, 2010 posting).

Bendable, stretchable, light-weight, and transparent: a new competitor in the competition for ‘thinnest electric generator’

An Oct. 15, 2014 Columbia University (New York, US) press release (also on EurekAlert), describes another contender for the title of the world’s thinnest electric generator,

Researchers from Columbia Engineering and the Georgia Institute of Technology [US] report today [Oct. 15, 2014] that they have made the first experimental observation of piezoelectricity and the piezotronic effect in an atomically thin material, molybdenum disulfide (MoS2), resulting in a unique electric generator and mechanosensation devices that are optically transparent, extremely light, and very bendable and stretchable.

In a paper published online October 15, 2014, in Nature, research groups from the two institutions demonstrate the mechanical generation of electricity from the two-dimensional (2D) MoS2 material. The piezoelectric effect in this material had previously been predicted theoretically.

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

Piezoelectricity of single-atomic-layer MoS2 for energy conversion and piezotronics by Wenzhuo Wu, Lei Wang, Yilei Li, Fan Zhang, Long Lin, Simiao Niu, Daniel Chenet, Xian Zhang, Yufeng Hao, Tony F. Heinz, James Hone, & Zhong Lin Wang. Nature (2014) doi:10.1038/nature13792 Published online 15 October 2014

This paper is behind a paywall. There is a free preview available with ReadCube Access.

Getting back to the Columbia University press release, it offers a general description of piezoelectricity and some insight into this new research on molybdenum disulfide,

Piezoelectricity is a well-known effect in which stretching or compressing a material causes it to generate an electrical voltage (or the reverse, in which an applied voltage causes it to expand or contract). But for materials of only a few atomic thicknesses, no experimental observation of piezoelectricity has been made, until now. The observation reported today provides a new property for two-dimensional materials such as molybdenum disulfide, opening the potential for new types of mechanically controlled electronic devices.

“This material—just a single layer of atoms—could be made as a wearable device, perhaps integrated into clothing, to convert energy from your body movement to electricity and power wearable sensors or medical devices, or perhaps supply enough energy to charge your cell phone in your pocket,” says James Hone, professor of mechanical engineering at Columbia and co-leader of the research.

“Proof of the piezoelectric effect and piezotronic effect adds new functionalities to these two-dimensional materials,” says Zhong Lin Wang, Regents’ Professor in Georgia Tech’s School of Materials Science and Engineering and a co-leader of the research. “The materials community is excited about molybdenum disulfide, and demonstrating the piezoelectric effect in it adds a new facet to the material.”

Hone and his research group demonstrated in 2008 that graphene, a 2D form of carbon, is the strongest material. He and Lei Wang, a postdoctoral fellow in Hone’s group, have been actively exploring the novel properties of 2D materials like graphene and MoS2 as they are stretched and compressed.

Zhong Lin Wang and his research group pioneered the field of piezoelectric nanogenerators for converting mechanical energy into electricity. He and postdoctoral fellow Wenzhuo Wu are also developing piezotronic devices, which use piezoelectric charges to control the flow of current through the material just as gate voltages do in conventional three-terminal transistors.

There are two keys to using molybdenum disulfide for generating current: using an odd number of layers and flexing it in the proper direction. The material is highly polar, but, Zhong Lin Wang notes, so an even number of layers cancels out the piezoelectric effect. The material’s crystalline structure also is piezoelectric in only certain crystalline orientations.

For the Nature study, Hone’s team placed thin flakes of MoS2 on flexible plastic substrates and determined how their crystal lattices were oriented using optical techniques. They then patterned metal electrodes onto the flakes. In research done at Georgia Tech, Wang’s group installed measurement electrodes on samples provided by Hone’s group, then measured current flows as the samples were mechanically deformed. They monitored the conversion of mechanical to electrical energy, and observed voltage and current outputs.

The researchers also noted that the output voltage reversed sign when they changed the direction of applied strain, and that it disappeared in samples with an even number of atomic layers, confirming theoretical predictions published last year. The presence of piezotronic effect in odd layer MoS2 was also observed for the first time.

“What’s really interesting is we’ve now found that a material like MoS2, which is not piezoelectric in bulk form, can become piezoelectric when it is thinned down to a single atomic layer,” says Lei Wang.

To be piezoelectric, a material must break central symmetry. A single atomic layer of MoS2 has such a structure, and should be piezoelectric. However, in bulk MoS2, successive layers are oriented in opposite directions, and generate positive and negative voltages that cancel each other out and give zero net piezoelectric effect.

“This adds another member to the family of piezoelectric materials for functional devices,” says Wenzhuo Wu.

In fact, MoS2 is just one of a group of 2D semiconducting materials known as transition metal dichalcogenides, all of which are predicted to have similar piezoelectric properties. These are part of an even larger family of 2D materials whose piezoelectric materials remain unexplored. Importantly, as has been shown by Hone and his colleagues, 2D materials can be stretched much farther than conventional materials, particularly traditional ceramic piezoelectrics, which are quite brittle.

The research could open the door to development of new applications for the material and its unique properties.

“This is the first experimental work in this area and is an elegant example of how the world becomes different when the size of material shrinks to the scale of a single atom,” Hone adds. “With what we’re learning, we’re eager to build useful devices for all kinds of applications.”

Ultimately, Zhong Lin Wang notes, the research could lead to complete atomic-thick nanosystems that are self-powered by harvesting mechanical energy from the environment. This study also reveals the piezotronic effect in two-dimensional materials for the first time, which greatly expands the application of layered materials for human-machine interfacing, robotics, MEMS, and active flexible electronics.

I see there’s a reference in that last paragraph to “harvesting mechanical energy from  the environment.” I’m not sure what they mean by that but I have written a few times about harvesting biomechanical energy. One of my earliest pieces is a July 12, 2010 post which features work by Zhong Lin Wang on harvesting energy from heart beats, blood flow, muscle stretching, or even irregular vibrations. One of my latest pieces is a Sept. 17, 2014 post about some work in Canada on harvesting energy from the jaw as you chew.

A final note, Dexter Johnson discusses this work in an Oct. 16, 2014 post on the Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website).

Replacing copper wire in motors?

Finnish researchers at Lappeenranta University of Technology (LUT) believe it may be possible to replace copper wire used in motors with spun carbon nanotubes. From an Oct. 15, 2014 news item on Azonano,

Lappeenranta University of Technology (LUT) introduces the first electrical motor applying carbon nanotube yarn. The material replaces copper wires in windings. The motor is a step towards lightweight, efficient electric drives. Its output power is 40 W and rotation speed 15000 rpm.

Aiming at upgrading the performance and energy efficiency of electrical machines, higher-conductivity wires are searched for windings. Here, the new technology may revolutionize the industry. The best carbon nanotubes (CNTs) demonstrate conductivities far beyond the best metals; CNT windings may have double the conductivity of copper windings.

”If we keep the design parameters unchanged only replacing copper with carbon nanotube yarns, the Joule losses in windings can be reduced to half of present machine losses. By lighter and more ecological CNT yarn, we can reduce machine dimensions and CO2 emissions in manufacturing and operation. Machines could also be run in higher temperatures,” says Professor Pyrhönen [Juha Pyrhönen], leading the prototype design at LUT.

An Oct. ??, 2014 (?) LUT press release, which originated the news item, further describes the work,

Traditionally, the windings in electrical machines are made of copper, which has the second best conductivity of metals at room temperature. Despite the high conductivity of copper, a large proportion of the electrical machine losses occur in the copper windings. For this reason, the Joule losses are often referred to as copper losses. The carbon nanotube yarn does not have a definite upper limit for conductivity (e.g. values of 100 MS/m have already been measured).

According to Pyrhönen, the electrical machines are so ubiquitous in everyday life that we often forget about their presence. In a single-family house alone there can be tens of electrical machines in various household appliances such as refrigerators, washing machines, hair dryers, and ventilators.

“In the industry, the number of electrical motors is enormous: there can be up to tens of thousands of motors in a single process industry unit. All these use copper in the windings. Consequently, finding a more efficient material to replace the copper conductors would lead to major changes in the industry,” tells Professor Pyrhönen.

There are big plans for this work according to the press release,

The prototype motor uses carbon nanotube yarns spun and converted into an isolated tape by a Japanese-Dutch company Teijin Aramid, which has developed the spinning technology in collaboration with Rice University, the USA. The industrial applications of the new material are still in their infancy; scaling up the production capacity together with improving the yarn performance will facilitate major steps in the future, believes Business Development Manager Dr. Marcin Otto from Teijin Aramid, agreeing with Professor Pyrhönen.

“There is a significant improvement potential in the electrical machines, but we are now facing the limits of material physics set by traditional winding materials. Superconductivity appears not to develop to such a level that it could, in general, be applied to electrical machines. Carbonic materials, however, seem to have a pole position: We expect that in the future, the conductivity of carbon nanotube yarns could be even three times the practical conductivity of copper in electrical machines. In addition, carbon is abundant while copper needs to be mined or recycled by heavy industrial processes.”

The researchers have produced this video about their research,

There’s a reference to some work done at Rice University (Texas, US) with Teijin Armid (Japanese-Dutch company) and Technion Institute (Israel) with spinning carbon nanotubes into threads that look like black cotton (you’ll see the threads in the video). It’s this work that has made the latest research in Finland possible. I have more about the the Rice/Teijin Armid/Technion CNT project in my Jan. 11, 2013 posting, Prima donna of nanomaterials (carbon nanotubes) tamed by scientists at Rice University (Texas, US), Teijin Armid (Dutch/Japanese company), and Technion Institute (based in Israel).

Silver nanoparticles: liquid on the outside, crystal on the inside

Research from the Massachusetts Institute of Technology (MIT) has revealed a new property of metal nanoparticles, in this case, silver. From an Oct. 12, 2014 news item on ScienceDaily,

A surprising phenomenon has been found in metal nanoparticles: They appear, from the outside, to be liquid droplets, wobbling and readily changing shape, while their interiors retain a perfectly stable crystal configuration.

The research team behind the finding, led by MIT professor Ju Li, says the work could have important implications for the design of components in nanotechnology, such as metal contacts for molecular electronic circuits.

The results, published in the journal Nature Materials, come from a combination of laboratory analysis and computer modeling, by an international team that included researchers in China, Japan, and Pittsburgh, as well as at MIT.

An Oct. 12, 2014 MIT news release (also on EurekAlert), which originated the news item, offers both more information about the research and a surprising comparison of nanometers to the width of a human hair,

The experiments were conducted at room temperature, with particles of pure silver less than 10 nanometers across — less than one-thousandth of the width of a human hair. [emphasis mine] But the results should apply to many different metals, says Li, senior author of the paper and the BEA Professor of Nuclear Science and Engineering.

Silver has a relatively high melting point — 962 degrees Celsius, or 1763 degrees Fahrenheit — so observation of any liquidlike behavior in its nanoparticles was “quite unexpected,” Li says. Hints of the new phenomenon had been seen in earlier work with tin, which has a much lower melting point, he says.

The use of nanoparticles in applications ranging from electronics to pharmaceuticals is a lively area of research; generally, Li says, these researchers “want to form shapes, and they want these shapes to be stable, in many cases over a period of years.” So the discovery of these deformations reveals a potentially serious barrier to many such applications: For example, if gold or silver nanoligaments are used in electronic circuits, these deformations could quickly cause electrical connections to fail.

It was a bit surprising to see the reference to 10 nanometers as being less than 1/1,000th (one/one thousandth) of the width of a human hair in a news release from MIT. Generally, a nanometer has been described as being anywhere from less than 1/50,000th to 1/120,000th of the width of a human hair with less than 1/100,000th being one of the most common descriptions. While it’s true that 10 nanometers is less than 1/1,000th of the width of a human hair, it seems a bit misleading when it could be described, in keeping with the more common description, as less than 1/10,000th.

Getting back to the research, the news release offers more details as to how it was conducted,

The researchers’ detailed imaging with a transmission electron microscope and atomistic modeling revealed that while the exterior of the metal nanoparticles appears to move like a liquid, only the outermost layers — one or two atoms thick — actually move at any given time. As these outer layers of atoms move across the surface and redeposit elsewhere, they give the impression of much greater movement — but inside each particle, the atoms stay perfectly lined up, like bricks in a wall.

“The interior is crystalline, so the only mobile atoms are the first one or two monolayers,” Li says. “Everywhere except the first two layers is crystalline.”

By contrast, if the droplets were to melt to a liquid state, the orderliness of the crystal structure would be eliminated entirely — like a wall tumbling into a heap of bricks.

Technically, the particles’ deformation is pseudoelastic, meaning that the material returns to its original shape after the stresses are removed — like a squeezed rubber ball — as opposed to plasticity, as in a deformable lump of clay that retains a new shape.

The phenomenon of plasticity by interfacial diffusion was first proposed by Robert L. Coble, a professor of ceramic engineering at MIT, and is known as “Coble creep.” “What we saw is aptly called Coble pseudoelasticity,” Li says.

Now that the phenomenon has been understood, researchers working on nanocircuits or other nanodevices can quite easily compensate for it, Li says. If the nanoparticles are protected by even a vanishingly thin layer of oxide, the liquidlike behavior is almost completely eliminated, making stable circuits possible.

There are some benefits to this insight (from the news release),

On the other hand, for some applications this phenomenon might be useful: For example, in circuits where electrical contacts need to withstand rotational reconfiguration, particles designed to maximize this effect might prove useful, using noble metals or a reducing atmosphere, where the formation of an oxide layer is destabilized, Li says.

The new finding flies in the face of expectations — in part, because of a well-understood relationship, in most materials, in which mechanical strength increases as size is reduced.

“In general, the smaller the size, the higher the strength,” Li says, but “at very small sizes, a material component can get very much weaker. The transition from ‘smaller is stronger’ to ‘smaller is much weaker’ can be very sharp.”

That crossover, he says, takes place at about 10 nanometers at room temperature — a size that microchip manufacturers are approaching as circuits shrink. When this threshold is reached, Li says, it causes “a very precipitous drop” in a nanocomponent’s strength.

The findings could also help explain a number of anomalous results seen in other research on small particles, Li says.

For more details about the various attempts to create smaller computer chips, you can read my July 11, 2014 posting about IBM and its proposed 7 nanometer chip where you will also find links to announcements and posts about Intel’s smaller chips and HP Labs’ attempt to recreate computers.

As for the research into liquid-like metallic (silver) nanoparticles, here’s a link to and a citation for the paper,

Liquid-like pseudoelasticity of sub-10-nm crystalline ​silver particle by Jun Sun, Longbing He, Yu-Chieh Lo, Tao Xu, Hengchang Bi, Litao Sun, Ze Zhang, Scott X. Mao, & Ju Li. Nature Materials (2014) doi:10.1038/nmat4105 Published online 12 October 2014

This paper is behind a paywall. There is a free preview via ReadCube Access.

Keeping your chef’s jackets clean and a prize for Teijin Aramid/Rice University

Australian start-up company, Fabricor Workwear launched a Kickstarter campaign on Sept. 18, 2014 to raise funds for a stain-proof and water-repellent chef’s jacket according to a Sept. 25, 2014 news item on Azonano,

An Australian startup is using a patented nanotechnology to create ‘hydrophobic’ chef jackets and aprons. Fabricor says this means uniforms that stay clean for longer, and saving time and money.

The company was started because cofounder and MasterChef mentor Adrian Li, was frustrated with keeping his chef jackets and aprons clean.

“As a chef I find it really difficult to keep my chef jacket white, and we like our jackets white,” Li said. …

The nanotechnology application works by modifying the fabric at a molecular level by permanently attaching hydrophobic ‘whiskers’ to individual fibres which elevate liquids, causing them to bead up and roll off.

The Fabricor: Stain-proof workwear for the hospitality industry Kickstarter campaign has this to say on its homepage (Note: Links have been removed),

Hi Kickstarters,

Thanks for taking the time check out our campaign.

Traditional chef jackets date back to the mid 19th century and since then haven’t changed much.

We’re tired of poor quality hospitality workwear that doesn’t last and hate spending our spare time and money washing or replacing our uniforms.

So we designed a range of stain-resistant Chef Jackets and Aprons using the world’s leading patented hydrophobic nanotechnology that repels water, dirt and oil.

Most stains either run off by themselves or can easily be rinsed off with a little water. This means they don’t need to be washed as often saving you time and money.

We’re really proud of what we’ve created and we hope you you’ll support us.

Adrian Li

Head Chef at Saigon Sally
Mentor on MasterChef Australia – Asian Street Food Challenge
Cofounder at Fabricor Workwear

At this point (Sept. 24, 2014), the campaign has raised approximately $2700US towards a $5000US goal and there are 22 days left to the campaign.

I did find more information at the Fabricor Workwear website in this Sept. 13, 2014 press release,

The fabric’s patented technology can extend the life of the apparel is because the apparel doesn’t have to be washed as often and can be washed in cooler temperatures, the company stated.

Fabricor’s products are not made with spray-application like many on the market which can destroy fabrics and contain carcinogenic chemical. Its hydrophobic properties are embedded into the weave during the production of the fabric.

Li said chefs spend too much money on chef jackets that are poorly designed and don’t last. The long-lasting fabric in Fabricor’s chef’s apparel retains its natural softness and breathability.

It seems to me that the claim about fewer washes can be made for all superhydrophobic textiles. As for carcinogenic chemicals in other superhydrophobic textiles, it’s the first I’ve heard of it, which may or may not be significant. I.e., I look at a lot of material but don’t focus on superhydrophobic textiles here and do not seek out research on risks specific to these textiles.

Teijin Aramid/Rice University

Still talking about textile fibres but on a completely different track, I received a news release this morning (Sept. 25, 2014) from Teijin Aramid about carbon nanotubes and fibres,

Researchers of Teijin Aramid, based in the Netherlands, and Rice University in the USA are awarded with the honorary ‘Paul Schlack Man-Made Fibers Prize’ for corporate-academic partnerships in fiber research. Their new super fibers are now driving innovation in aerospace, healthcare, automotive, and (smart) clothing.

The honorary Paul Schlack prize was granted by the European Man-made Fibers Association to Dr. Marcin Otto, Business Development Manager at Teijin Aramid and Prof. Dr. Matteo Pasquali from Rice University Texas, for the development of a new generation super fibers using carbon nanotubes (CNT). The new super fibers combine high thermal and electrical conductivity, as seen in metals, with the flexibility, robust handling and strength of textile fibers.

“The introduction of carbon nanotube fibers marked the beginning of a series of innovations in various industries”, says Marcin Otto, Business Development Manager at Teijin Aramid. “For example, CNT fibers can be lifesaving for heart patients: one string of CNT fiber in the cardiac muscle suffices to transmit vital electrical pulses to the heart. Or by replacing copper in data cables and light power cables by CNT fibers it’s possible to make satellites, aircraft and high end cars lighter and more robust at the same time.”

Since 1971, the Paul Schlack foundation annually grants one monetary prize to an individual young researcher for outstanding research in the field of fiber research, and an honorary prize to the leader(s) of excellent academic and corporate research partnerships to promote research at universities and research institutes.

For several years, leading researchers at Rice University and Teijin Aramid worked together on the development of CNT production. Teijin Aramid and Rice University published their research findings on carbon nanotubes fibers in the leading scientific journal, Science, beginning of 2013.

Teijin Aramid and some of its carbon nanotube projects have been mentioned here before, notably, in a Jan. 11, 2013 posting and in a Feb. 17, 2014.

Good luck on the Kickstarter campaign and congratulations on the award!

Canadian researchers harvest energy from chewing

Who knew that jaw movements have proved to be amongst the most promising activities for energy-harvesting? Apparently, scientists know and are coming up with ways to enjoy the harvest. From a Sept. 16, 2014 news item on Nanowerk,

A chin strap that can harvest energy from jaw movements has been created by a group of researchers in Canada.

It is hoped that the device can generate electricity from eating, chewing and talking, and power a number of small-scale implantable or wearable electronic devices, such as hearing aids, cochlear implants, electronic hearing protectors and communication devices.

An Institute of Physics (IOP) Sept. 16, 2014 news release (also on EurekAlert), which  generated the news item, explains just why jaw movements are so exciting and how the researchers went about ‘harvesting’,

Jaw movements have proved to be one of the most promising candidates for generating electricity from human body movements, with researchers estimating that an average of around 7 mW of power could be generated from chewing during meals alone.

To harvest this energy, the study’s researchers, from Sonomax-ÉTS Industrial Research Chair in In-ear Technologies (CRITIAS) at École de technologie supérieure (ÉTS) in Montreal, Canada, created a chinstrap made from piezoelectric fibre composites (PFC).

PFC is a type of piezoelectric smart material that consists of integrated electrodes and an adhesive polymer matrix. The material is able to produce an electric charge when it stretches and is subjected to mechanical stress.

In their study, the researchers created an energy-harvesting chinstrap made from a single layer of PFC and attached it to a pair of earmuffs using a pair of elastic side straps. To ensure maximum performance, the chinstrap was fitted snugly to the user, so when the user’s jaw moved it caused the strap to stretch.

To test the performance of the device, the subject was asked to chew gum for 60 seconds while wearing the device; at the same time the researchers recorded a number of different parameters.

The maximum amount of power that could be harvested from the jaw movements was around 18 µW, but taking into account the optimum set-up for the head-mounted device, the power output was around 10 µW.

Co-author of the study Aidin Delnavaz said: “Given that the average power available from chewing is around 7 mW, we still have a long way to go before we perfect the performance of the device.

“The power level we achieved is hardly sufficient for powering electrical devices at the moment; however, we can multiply the power output by adding more PFC layers to the chinstrap. For example, 20 PFC layers, with a total thickness of 6 mm, would be able to power a 200 µW intelligent hearing protector.”

One additional motivation for pursuing this area of research is the desire to curb the current dependency on batteries, which are not only expensive to replace but also extremely damaging to the environment if they are not disposed of properly.

“The only expensive part of the energy-harvesting device is the single PFC layer, which costs around $20. Considering the price and short lifetime of batteries, we estimate that a self-powered hearing protector based on the proposed chinstrap energy-harvesting device will start to pay back the investment after three years of use,” continued Delnavaz.

“Additionally, the device could substantially decrease the environmental impact of batteries and bring more comfort to users.

“We will now look at ways to increase the number of piezoelectric elements in the chinstrap to supply the power that small electronic devices demand, and also develop an appropriate power management circuit so that a tiny, rechargeable battery can be integrated into the device.”

Here’s a look at the ‘smart chinstrap’,

Caption: This is the experimental set up of an energy harvesting chin strap. Credit: Smart Materials and Structures/IOP Publishing

Caption: This is the experimental set up of an energy harvesting chin strap.
Credit: Smart Materials and Structures/IOP Publishing

I don’t see anyone rushing to get a chinstrap soon. Hopefully they’ll find a way to address some of the design issues. In the meantime, here’s a link to and a citation for the paper,

Flexible piezoelectric energy harvesting from jaw movements by Aidin Delnavaz and Jérémie Voix. 2014 Smart Mater. Struct. 23 105020 doi:10.1088/0964-1726/23/10/105020

This is an open access paper.

Silicene in Saskatchewan (Canada)

There’s some very exciting news coming out of the province of Saskatchewan (Canada) about silicene, a material some view as a possible rival to graphene (although that’s problematic according to my Jan. 12, 2014 posting) while others (US National Argonne Laboratory) challenge its existence (my Aug. 1,  2014 posting).

The researchers in Saskatchewan seem quite confident in silicene’s existence according to a Sept. 9, 2014 news item on phys.org,

“Once a device becomes too small it falls prey to the strange laws of the quantum world,” says University of Saskatchewan researcher Neil Johnson, who is using the Canadian Light Source synchrotron to help develop the next generation of computer materials. Johnson is a member of Canada Research Chair Alexander Moewes’ group of graduate students studying the nature of materials using synchrotron radiation.

His work focuses on silicene, a recent and exciting addition to the class of two-dimensional materials. Silicene is made up of an almost flat hexagonal pattern of silicon atoms. Every second atom in each hexagonal ring is slightly lifted, resulting in a buckled sheet that looks the same from the top or the bottom.

A Sept. 9, 2014 Canadian Light Source news release, which originated the news item, provides background as to how Johnson started studying silicene and some details about the work,

In 2012, mere months before Johnson began to study silicene, it was discovered and first created by the research group of Prof. Guy Le Lay of Aix-Marseille University, using silver as a base for the thin film. The Le Lay group is the world-leader in silicene growth, and taught Johnson and his colleagues how to make it at the CLS themselves.

“I read the paper when the Le Lay announced they had made silicene, and within three or four months, Alex had arranged for us to travel down to the Advanced Light Source with these people who had made it for the first time,” says Johnson. It was an exciting collaboration for the young physicist.

“This paper had already been cited over a hundred times in a matter of months. It was a major paper, and we were going to measure this new material that no one had really started doing experiments on yet.”

The most pressing question facing silicene research was its potential as a semiconductor. Today, most electronics use silicon as a switch, and researchers looking for new materials to manage quantum effects in computing could easily use the 2-D version if it was also semiconducting.

Calculations had shown that because of the special buckling of silicene, it would have what’s called a Dirac cone – a special electronic structure that could allow researchers to tune the band gap, or the energy space between electron levels. The band gap is what makes a semiconductor: if the space is too small, the material is simply a conductor. Too large, and there is no conduction at all.

Since silicene has only ever been made on a silver base, the materials community also wondered if silicene would maintain its semiconducting properties in this condition. Though its atomic structure is slightly different than freestanding silicene, it was still predicted to have a band gap. However, silver is a metal, which may make the silicene act as a metal as well.

No one really knew how silicene would behave on its silver base.

To adapt the Le Lay group’s silicene-growing process to the equipment at the CLS took several days of work. Though their team had succeeded in silicene synthesis at the Advanced Light Source at Berkeley lab, they had no way to keep those samples under vacuum to prevent them from oxygen damage. Thanks to the work of fellow beamteam members Drs. David Muir and Israel Perez, samples grown at the CLS could be produced, transported and measured in a matter of hours without ever leaving a vacuum chamber.

Johnson grew the silicene sheets at the Resonant Elastic and Inelastic X-ray Scattering (REIXS), beamline, then transferred them in a vacuum to the XAS/XES endstation for analysis. Finally, Johnson could find the answer to the silicene question.

“I didn’t really know what to expect until I saw the XAS and XES on the same energy scale, and I thought to myself, that looks like a metal,” says Johnson.

And while that result is unfortunate for those searching for a new computing wonder material, it does provide some vital information to that search.

“Our result does help to guide the hunt for 2-D silicon in the future, suggesting that metallic substrates should be avoided at all costs,” Johnson explains. “We’re hopeful that we can grow a similar structure on other substrates, ideally ones that leave the semiconducting nature of silicene intact.”

That work is already in process, with Johnson and his colleagues planning to explore three other growing bases this summer, along with multilayers and nanoribbons of silicene.

Like the Dutch researchers in the Jan. 12, 2014 posting, Johnson finds that silicene is not serious competition for graphene (as regards to its electrical properties), but he does not challenge its existence. He does note problems with the silver substrate although he comes to a different conclusion than did the Argonne National Laboratory researchers (Aug. 1,  2014 posting).

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

The Metallic Nature of Epitaxial Silicene Monolayers on Ag(111) by Neil W. Johnson, Patrick Vogt, Andrea Resta, Paola De Padova, Israel Perez, David Muir, Ernst Z. Kurmaev, Guy Le Lay, and Alexander Moewes. Advanced Functional Materials Volume 24, Issue 33, pages 5253–5259, September 3, 2014 DOI: 10.1002/adfm.201400769 Article first published online: 10 JUN 2014

This paper is behind a paywall.

Buckydiamondoids steer electron flow

One doesn’t usually think about buckyballs (Buckminsterfullerenes) and diamondoids as being together in one molecule but that has not stopped scientists from trying to join them and, in this case, successfully. From a Sept. 9, 2014 news item on ScienceDaily,

Scientists have married two unconventional forms of carbon — one shaped like a soccer ball, the other a tiny diamond — to make a molecule that conducts electricity in only one direction. This tiny electronic component, known as a rectifier, could play a key role in shrinking chip components down to the size of molecules to enable faster, more powerful devices.

Here’s an illustration the scientists have provided,

Illustration of a buckydiamondoid molecule under a scanning tunneling microscope (STM). In this study the STM made images of the buckydiamondoids and probed their electronic properties.

Illustration of a buckydiamondoid molecule under a scanning tunneling microscope (STM). In this study the STM made images of the buckydiamondoids and probed their electronic properties.

A Sept. 9, 2014 Stanford University news release by Glenda Chui (also on EurekAlert), which originated the news item, provides some information about this piece of international research along with background information on buckyballs and diamondoids (Note: Links have been removed),

“We wanted to see what new, emergent properties might come out when you put these two ingredients together to create a ‘buckydiamondoid,'” said Hari Manoharan of the Stanford Institute for Materials and Energy Sciences (SIMES) at the U.S. Department of Energy’s SLAC National Accelerator Laboratory. “What we got was basically a one-way valve for conducting electricity – clearly more than the sum of its parts.”

The research team, which included scientists from Stanford University, Belgium, Germany and Ukraine, reported its results Sept. 9 in Nature Communications.

Many electronic circuits have three basic components: a material that conducts electrons; rectifiers, which commonly take the form of diodes, to steer that flow in a single direction; and transistors to switch the flow on and off. Scientists combined two offbeat ingredients – buckyballs and diamondoids – to create the new diode-like component.

Buckyballs – short for buckminsterfullerenes – are hollow carbon spheres whose 1985 discovery earned three scientists a Nobel Prize in chemistry. Diamondoids are tiny linked cages of carbon joined, or bonded, as they are in diamonds, with hydrogen atoms linked to the surface, but weighing less than a billionth of a billionth of a carat. Both are subjects of a lot of research aimed at understanding their properties and finding ways to use them.

In 2007, a team led by researchers from SLAC and Stanford discovered that a single layer of diamondoids on a metal surface can emit and focus electrons into a tiny beam. Manoharan and his colleagues wondered: What would happen if they paired an electron-emitting diamondoid with another molecule that likes to grab electrons? Buckyballs are just that sort of electron-grabbing molecule.

Details are then provided about this specific piece of research (from the Stanford news release),

For this study, diamondoids were produced in the SLAC laboratory of SIMES researchers Jeremy Dahl and Robert Carlson, who are world experts in extracting the tiny diamonds from petroleum. The diamondoids were then shipped to Germany, where chemists at Justus-Liebig University figured out how to attach them to buckyballs.

The resulting buckydiamondoids, which are just a few nanometers long, were tested in SIMES laboratories at Stanford. A team led by graduate student Jason Randel and postdoctoral researcher Francis Niestemski used a scanning tunneling microscope to make images of the hybrid molecules and measure their electronic behavior. They discovered that the hybrid is an excellent rectifier: The electrical current flowing through the molecule was up to 50 times stronger in one direction, from electron-spitting diamondoid to electron-catching buckyball, than in the opposite direction. This is something neither component can do on its own.

While this is not the first molecular rectifier ever invented, it’s the first one made from just carbon and hydrogen, a simplicity researchers find appealing, said Manoharan, who is an associate professor of physics at Stanford. The next step, he said, is to see if transistors can be constructed from the same basic ingredients.

“Buckyballs are easy to make – they can be isolated from soot – and the type of diamondoid we used here, which consists of two tiny cages, can be purchased commercially,” he said. “And now that our colleagues in Germany have figured out how to bind them together, others can follow the recipe. So while our research was aimed at gaining fundamental insights about a novel hybrid molecule, it could lead to advances that help make molecular electronics a reality.”

Other research collaborators came from the Catholic University of Louvain in Belgium and Kiev Polytechnic Institute in Ukraine. The primary funding for the work came from U.S. the Department of Energy Office of Science (Basic Energy Sciences, Materials Sciences and Engineering Divisions).

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

Unconventional molecule-resolved current rectification in diamondoid–fullerene hybrids by Jason C. Randel, Francis C. Niestemski,    Andrés R. Botello-Mendez, Warren Mar, Georges Ndabashimiye, Sorin Melinte, Jeremy E. P. Dahl, Robert M. K. Carlson, Ekaterina D. Butova, Andrey A. Fokin, Peter R. Schreiner, Jean-Christophe Charlier & Hari C. Manoharan. Nature Communications 5, Article number: 4877 doi:10.1038/ncomms5877 Published 09 September 2014

This paper is open access. The scientists provided not only a standard illustration but a pretty picture of the buckydiamondoid,

Caption: An international team led by researchers at SLAC National Accelerator Laboratory and Stanford University joined two offbeat carbon molecules -- diamondoids, the square cages at left, and buckyballs, the soccer-ball shapes at right -- to create "buckydiamondoids," center. These hybrid molecules function as rectifiers, conducting electrons in only one direction, and could help pave the way to molecular electronic devices. Credit: Manoharan Lab/Stanford University

Caption: An international team led by researchers at SLAC National Accelerator Laboratory and Stanford University joined two offbeat carbon molecules — diamondoids, the square cages at left, and buckyballs, the soccer-ball shapes at right — to create “buckydiamondoids,” center. These hybrid molecules function as rectifiers, conducting electrons in only one direction, and could help pave the way to molecular electronic devices.
Credit: Manoharan Lab/Stanford University

Nanoscale light confinement without metal (photonic circuits) at the University of Alberta (Canada)

To be more accurate, this is a step forward towards photonic circuits according to an Aug. 20, 2014 news item on Azonano,

The invention of fibre optics revolutionized the way we share information, allowing us to transmit data at volumes and speeds we’d only previously dreamed of. Now, electrical engineering researchers at the University of Alberta are breaking another barrier, designing nano-optical cables small enough to replace the copper wiring on computer chips.

This could result in radical increases in computing speeds and reduced energy use by electronic devices.

“We’re already transmitting data from continent to continent using fibre optics, but the killer application is using this inside chips for interconnects—that is the Holy Grail,” says Zubin Jacob, an electrical engineering professor leading the research. “What we’ve done is come up with a fundamentally new way of confining light to the nano scale.”

At present, the diameter of fibre optic cables is limited to about one thousandth of a millimetre. Cables designed by graduate student Saman Jahani and Jacob are 10 times smaller—small enough to replace copper wiring still used on computer chips. (To put that into perspective, a dime is about one millimetre thick.)

An Aug. 19, 2014 University of Alberta news release by Richard Cairney (also on EurekAlert), which originated the news item, provides more technical detail and information about funding,

 Jahani and Jacob have used metamaterials to redefine the textbook phenomenon of total internal reflection, discovered 400 years ago by German scientist Johannes Kepler while working on telescopes.

Researchers around the world have been stymied in their efforts to develop effective fibre optics at smaller sizes. One popular solution has been reflective metallic claddings that keep light waves inside the cables. But the biggest hurdle is increased temperatures: metal causes problems after a certain point.

“If you use metal, a lot of light gets converted to heat. That has been the major stumbling block. Light gets converted to heat and the information literally burns up—it’s lost.”

Jacob and Jahani have designed a new, non-metallic metamaterial that enables them to “compress” and contain light waves in the smaller cables without creating heat, slowing the signal or losing data. …

The team’s research is funded by the Natural Sciences and Engineering Research Council of Canada and the Helmholtz-Alberta Initiative.

Jacob and Jahani are now building the metamaterials on a silicon chip to outperform current light confining strategies used in industry.

Given that this work is being performed at the nanoscale and these scientists are located within the Canadian university which houses Canada’s National Institute of Nanotechnology (NINT), the absence of any mention of the NINT comes as a surprise (more about this organization after the link to the researchers’ paper).

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

Transparent subdiffraction optics: nanoscale light confinement without metal by Saman Jahani and Zubin Jacob. Optica, Vol. 1, Issue 2, pp. 96-100 (2014) http://dx.doi.org/10.1364/OPTICA.1.000096

This paper is open access.

In a search for the NINT’s website I found this summary at the University of Alberta’s NINT webpage,

The National Institute for Nanotechnology (NINT) was established in 2001 and is operated as a partnership between the National Research Council and the University of Alberta. Many NINT researchers are affiliated with both the National Research Council and University of Alberta.

NINT is a unique, integrated, multidisciplinary institute involving researchers from fields such as physics, chemistry, engineering, biology, informatics, pharmacy, and medicine. The main focus of the research being done at NINT is the integration of nano-scale devices and materials into complex nanosystems that can be put to practical use. Nanotechnology is a relatively new field of research, so people at NINT are working to discover “design rules” for nanotechnology and to develop platforms for building nanosystems and materials that can be constructed and programmed for a particular application. NINT aims to increase knowledge and support innovation in the area of nanotechnology, as well as to create work that will have long-term relevance and value for Alberta and Canada.

The University of Alberta’s NINT webpage also offers a link to the NINT’s latest rebranded website, The failure to mention the NINT gets more curious when looking at a description of NINT’s programmes one of which is hybrid nanoelectronics (Note: A link has been removed),

Hybrid NanoElectronics provide revolutionary electronic functions that may be utilized by industry through creating circuits that operate using mechanisms unique to the nanoscale. This may include functions that are not possible with conventional circuitry to provide smaller, faster and more energy-efficient components, and extend the development of electronics beyond the end of the roadmap.

After looking at a list of the researchers affiliated with the NINT, it’s apparent that neither Jahani or Jacob are part of that team. Perhaps they have preferred to work independently of the NINT ,which is one of the Canada National Research Council’s institutes.

Cyborgs (a presentation) at the American Chemical Society’s 248th meeting

There will be a plethora of chemistry news online over the next few days as the American Society’s (ACS) 248th meeting in San Francisco, CA from Aug. 10 -14, 2014 takes place. Unexpectedly, an Aug. 11, 2014 news item on Azonano highlights a meeting presentation focused on cyborgs,

No longer just fantastical fodder for sci-fi buffs, cyborg technology is bringing us tangible progress toward real-life electronic skin, prosthetics and ultraflexible circuits. Now taking this human-machine concept to an unprecedented level, pioneering scientists are working on the seamless marriage between electronics and brain signaling with the potential to transform our understanding of how the brain works — and how to treat its most devastating diseases.

An Aug. 10, 2014 ACS news release on EurekAlert provides more detail about the presentation (Note: Links have been removed),

“By focusing on the nanoelectronic connections between cells, we can do things no one has done before,” says Charles M. Lieber, Ph.D. “We’re really going into a new size regime for not only the device that records or stimulates cellular activity, but also for the whole circuit. We can make it really look and behave like smart, soft biological material, and integrate it with cells and cellular networks at the whole-tissue level. This could get around a lot of serious health problems in neurodegenerative diseases in the future.”

These disorders, such as Parkinson’s, that involve malfunctioning nerve cells can lead to difficulty with the most mundane and essential movements that most of us take for granted: walking, talking, eating and swallowing.

Scientists are working furiously to get to the bottom of neurological disorders. But they involve the body’s most complex organ — the brain — which is largely inaccessible to detailed, real-time scrutiny. This inability to see what’s happening in the body’s command center hinders the development of effective treatments for diseases that stem from it.

By using nanoelectronics, it could become possible for scientists to peer for the first time inside cells, see what’s going wrong in real time and ideally set them on a functional path again.

For the past several years, Lieber has been working to dramatically shrink cyborg science to a level that’s thousands of times smaller and more flexible than other bioelectronic research efforts. His team has made ultrathin nanowires that can monitor and influence what goes on inside cells. Using these wires, they have built ultraflexible, 3-D mesh scaffolding with hundreds of addressable electronic units, and they have grown living tissue on it. They have also developed the tiniest electronic probe ever that can record even the fastest signaling between cells.

Rapid-fire cell signaling controls all of the body’s movements, including breathing and swallowing, which are affected in some neurodegenerative diseases. And it’s at this level where the promise of Lieber’s most recent work enters the picture.

In one of the lab’s latest directions, Lieber’s team is figuring out how to inject their tiny, ultraflexible electronics into the brain and allow them to become fully integrated with the existing biological web of neurons. They’re currently in the early stages of the project and are working with rat models.

“It’s hard to say where this work will take us,” he says. “But in the end, I believe our unique approach will take us on a path to do something really revolutionary.”

Lieber acknowledges funding from the U.S. Department of Defense, the National Institutes of Health and the U.S. Air Force.

I first covered Lieber’s work in an Aug. 27, 2012 posting  highlighting some good descriptions from Lieber and his colleagues of their work. There’s also this Aug. 26, 2012 article by Peter Reuell in the Harvard Gazette (featuring a very good technical description for someone not terribly familiar with the field but able to grasp some technical information while managing their own [mine] ignorance). The posting and the article provide details about the foundational work for Lieber’s 2014 presentation at the ACS meeting.

Lieber will be speaking next at the IEEE (Institute for Electrical and Electronics Engineers) 14th International Conference on Nanotechnology sometime between August 18 – 21, 2014 in Toronto, Ontario, Canada.

As for some of Lieber’s latest published work, there’s more information in my Feb. 20, 2014 posting which features a link to a citation for the paper (behind a paywall) in question.