Monthly Archives: September 2013

Accelerator-on-a-chip at Stanford University’s SLAC National Accelerator Laboratory

For anyone who’s ever seen a picture of the accelerators at CERN’s (European Particle Physics Laboratory) Large Hadron Collider, the notion of an accelerator-on-a-chip seems unbelievable. Scientists at Stanford’s SLAC National Accelerator Laboratory thought otherwise according to a Sept. 27, 2013 SLAC news release (also on EurekAlert),

In an advance that could dramatically shrink particle accelerators for science and medicine, researchers used a laser to accelerate electrons at a rate 10 times higher than conventional technology in a nanostructured glass chip smaller than a grain of rice.

“We still have a number of challenges before this technology becomes practical for real-world use, but eventually it would substantially reduce the size and cost of future high-energy particle colliders for exploring the world of fundamental particles and forces,” said Joel England, the SLAC physicist who led the experiments. “It could also help enable compact accelerators and X-ray devices for security scanning, medical therapy and imaging, and research in biology and materials science.”

Because it employs commercial lasers and low-cost, mass-production techniques, the researchers believe it will set the stage for new generations of “tabletop” accelerators.

At its full potential, the new “accelerator on a chip” could match the accelerating power of SLAC’s 2-mile-long linear accelerator in just 100 feet, and deliver a million more electron pulses per second. [emphasis mine]

The news release goes on to describe how the researchers have achieved a more efficient acceleration,

Particles are generally accelerated in two stages. First they are boosted to nearly the speed of light. Then any additional acceleration increases their energy, but not their speed; this is the challenging part.

In the accelerator-on-a-chip experiments, electrons are first accelerated to near light-speed in a conventional accelerator. Then they are focused into a tiny, half-micron-high channel within a fused silica glass chip just half a millimeter long. The channel had been patterned with precisely spaced nanoscale ridges. Infrared laser light shining on the pattern generates electrical fields that interact with the electrons in the channel to boost their energy.

The researchers’ have produced an animation which illustrates their work,

Caption: This animation explains how the accelerator on a chip uses infrared laser light to accelerate electrons to increasingly higher energies. Credit:  (Greg Stewart/SLAC)

Here’s a citation for and a link to the  research paper (‘near final version as of Sept. 30, 2013),

Demonstration of electron acceleration in a laser-driven dielectric microstructure by E. A. Peralta, K. Soong, R. J. England, E. R. Colby, Z. Wu, B. Montazeri, C. McGuinness, J. McNeur, K. J. Leedle, D. Walz, E. B. Sozer, B. Cowan, B. Schwartz, G. Travish, & R. L. Byer. Nature (2013) doi:10.1038/nature12664  Published online 27 September 2013

It is behind a paywall although you can get reading access via ReadCube.

Finally, here’s what the chip looks like,

Nanofabricated chips of fused silica just 3 millimeters long were used to accelerate electrons at a rate 10 times higher than conventional particle accelerator technology. (Brad Plummer/SLAC)

Nanofabricated chips of fused silica just 3 millimeters long were used to accelerate electrons at a rate 10 times higher than conventional particle accelerator technology. (Brad Plummer/SLAC)

Opposite world: developing anti-adhesion surfaces

The power of the metaphor/analogy is demonstrated in a Sept. 24, 2013 news item on ScienceDaily where they’ve mentioned insects in the context of anti-adhesion—the opposite of how insects are usually referenced, i.e., how well they stick to surfaces and the search for better adhesives. Or you could put it down to lazy reading on my part as it took me a minute or so to make sense of what I was reading (from the news item),

Beetles, cockroaches, and ants will have a harder time walking up the sides of buildings or air conditioners in the future — thanks to the bio-inspired, anti-adhesive surfaces Prof. Dr. Thomas Speck, Dr. Bettina Prüm, and Dr. Holger Bohn are developing together with the Plant Biomechanics Group of the University of Freiburg. The team studied plant surfaces in order to determine what influence cell form and microstructure as well as surface chemistry exert on the adhesion behavior of insects.

The Sept. 24, 2013 University of Freiburg (Germany) press release,which originated the news item, describes the research and the new anti-adhesive surface in more detail,

The researchers conducted adhesion experiments in which Colorado potato beetles walked across differently structured plant surfaces as well as replicas made of synthetic resins. The team used a highly sensitive sensor to measure the traction forces of the beetles on various surfaces. They discovered that wavy or strongly curved cells can increase the adhesive powers of beetles, whereas microstructures composed of wax crystals or cuticular folds reduce them. The latter are tiny folds in the cuticle, a protective layer on the surface of the leaf resembling polyester. The beetles had the hardest time walking on surfaces with cuticular folds with a height and width of approximately 0.5 micrometers and a spacing of between 0.5 and 1.5 micrometers. “That is the perfect anti-adhesion surface. The insects slip off of it much easier than off glass,” says project director Thomas Speck. The cuticular folds reduce the contact area between the adhesive hairs on the beetles’ legs and the plant surface. Unlike on more coarsely structured surfaces, the beetle can’t dig its feet firmly into the cuticular folds. Thus, the microstructure of the surface has a stronger effect on the adhesion of the beetle than the cell form.

The team also took contact angle measurements to investigate the wettability of the various surfaces. The researchers used hydrophobic and hydrophilic artificial moldings of the microstructured plant surfaces in order to study the influence of the surface chemistry on surface wettability and the beetles’ walking behavior. Much like wax crystals, cuticular folds are very good at repelling water. In contrast to the wettability, which depends on both the microstructure and the surface chemistry, the walking behavior of the beetles is not influenced by the surface chemistry. This means that the beetle’s adhesive power depends solely on the physical microstructure of the surface.

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

Plant surfaces with cuticular folds and their replicas: Influence of microstructuring and surface chemistry on the attachment of a leaf beetle by Bettina Prüm, Holger Florian Bohn, Robin Seidel, Stephan Rubach, and Thomas Speck. Acta Biomaterialia Volume 9, Issue 5, May 2013, Pages 6360–6368

This paper is behind a paywall.

DARPA (US Defense Advanced Research Projects Agency) wants to crowdsource cheap brain-computer interfaces

The US Defense Advanced Research Projects Agency wants the DIY (or Maker community) to develop inexpensive brain-computer interfaces according to a Sept. 27, 2013 news item by John Hewitt on,

This past Saturday [Sept. 21, 2013], at the Maker Faire in New York, a new low-cost EEG recording front end was debuted at DARPA’s booth. Known as OpenBCI, the device can process eight channels of high quality EEG data, and interface it to popular platforms like Arduino. …

DARPA program manager William Casebeer said that his goal was to return next year to the Maker meeting with a device that costs under $30.

Adrianne Jeffries’ Sept. 22, 2013 article for The Verge provides more information (Note: Links have been removed),

A working prototype of a low-cost electroencephalography device funded by the US Defense Advanced Research Projects Agency (DARPA) made its debut in New York this weekend [Sept. 21 – 22, 2013], the first step in the agency’s effort to jumpstart a do-it-yourself revolution in neuroscience.
There are some products like those in the Neurosky lineup, which range from $99 to $130. But most neural monitoring tools are relatively expensive and proprietary, the OpenBCI [OpenBCI, an open source device built to capture signals from eight electrodes at a time] team explained, which makes it tough for the casual scientist, hacker, or artist to play with EEG. If neural monitoring were cheap and open, we’d start to see more science experiments, art projects, mind-controlled video games, and even serious research using brainwaves. You could use an at-home EEG to create a brain-powered keyboard, for example, Dr. Allen [Lindsey Allen, engineer for Creare;  OpenBCI was built by Creare and biofeedback scientist Joel Murphy, and the prototype was finished only two weeks ago] said, and learn how to type with your mind.

I have written about various brain-computer interfaces previously, the most recent being a Dec. 5, 2012 posting about Muse, a $199 brainwave computer controller.

Czech nanotechnology efforts in China

There’s a Sept. 27, 2013 news item about the Czech Republic’s latest technology mission to China on the Nanowerk website,

This week [Sept.  23 – 27, 2013], the representatives of Czech nanotechnology firms, two famous technical universities and CzechInvest took part in a technology mission to China, where they met Chinese counterparts and discussed the further strengthening of cooperation in the field of nanotechnology. This technology mission to China, together with activities of some Czech nanotechnology companies, which have also been extensively supported by the Czech embassy in Beijing in recent months, has brought new opportunities for investment and the further collaboration of highly innovative technologies originated in the Czech Republic.

The Sept. 25, 2013 Czechinvest news release, which originated the news item,  offers more details about the mission,

“The Czech Republic is a world leader in the field of nanotechnology, which has an impact on numerous industrial sectors and places major demands on research. Czech nanotechnology firms are highly respected on the Chinese market,” says Marian Piecha, CEO of CzechInvest.

Representatives of CzechInvest, the Technical University of Liberec, Brno University of Technology and the Czech nanotechnology firms NAFIGATE Corporation, Elmarco, ACT Nami and Noen are taking part in CHINanoForum 2013, which is being held from 24 to 27 September in Jiangsu province. Within the forum’s accompanying programme, CzechInvest and NAFIGATE Corporation conducted a seminar title Nanosolutions for Green Economy – Investment Opportunity in China on 24 September. On 27 September the Czech delegates and their Chinese counterparts will be at the Czech embassy in Beijing to discuss the topic of using nanotechnologies in water treatment, among other things.

“China offers tremendous space for introducing new high-tech products to the market,” says Ladislav Mareš, chairman of the board of directors of NAFIGATE Corporation. “This technology mission therefore has major significance for supporting Czech exports to the Chinese market. Presentation of the potential of Czech nanotechnologies is also a signal for Chinese investors.”

According to the news release, a memorandum of understanding will be signed,

Technological cooperation between the two countries will also be supported by the signing of a Memorandum of Understanding between the Technology Agency of the Czech Republic and the Suzhou Industrial Park Administrative Committee. The signing of the memorandum, which will facilitate cooperation between Czech and Chinese firms with a high technological profile, will be attended by representatives of CzechInvest and His Excellency Libor Sečka, the Czech ambassador in China.

Earlier this years,  in June 2013, Nafigate signed a letter of intent with its Chinese partner, Guodian Technology & Environment Group Corporation Limited, regarding the development of a green nanotechnology centre. From a June 21, 2013 news release on PR newswire,

In the last few days, Czech nanotechnology pioneers have been presenting possible ways of utilizing Czech nanotechnology with specific examples taken from the Clean Air Nanosolution and Clean Water Nanosolution projects to representatives of the most significant Chinese companies at the Embassy of the Czech Republic in Beijing. “There is a lot of interest in the new technology because it solves fundamental problems in air and water cleaning. At the same time the Czech Republic is the world leader in the field of nanofibers and has much to offer China, from cooperation in research and development to putting specific innovative approaches into practice. Cooperation in this field could become an important new branch of mutual trade and scientific and technological exchanges and bring qualitative changes in the life of Chinese society,” said H. E. Mr. Libor Secka, Ambassador of the Czech Republic to the People’s Republic of China.

The signing of the Letter of Intent between NAFIGATE China (a subsidiary of the Czech company NAFIGATE Corporation JSC) and their Chinese partner Guodian Technology & Environment Group Corporation Limited (a subsidiary of one of the most prominent Chinese energy companies) is a significant milestone in Czech-Chinese cooperation in nanotechnology sector. Since January 2013 both companies have been preparing the foundation of the NANODEC (Nanofiber Development Center) project for the development of final applications for water and air cleaning.

The establishment of the center will be a major breakthrough with a global impact in the field of nanofiber applications. The aim of this initiative is to build a center of excellence which will utilize the best available worldwide know-how, the technological and infrastructural potential of one of the most significant Chinese companies and the potential of the market for new low carbon and green technologies. The Letter of Intent specifies the steps required to open the center according to the schedule in the last quarter of 2013.

For those interested in the overall nanotechnology scene in the Czech Republic, I found a 2012 article in the New York Times and a paper (2009?)  written for the National Information Centre For European Research (NICER) and located on the Organization of Economic Cooperation and Development.

Here’s some of what Jacy Meyer wrote for the New York Times in a May 22, 2012 article,

Industries based on nanotechnology are a rapidly growing niche in the economy of the Czech Republic, which, although small, is widely respected for its technical prowess. In February, the country had its own pavilion at the International Nanotechnology Trade Fair, Nanotech 2012, in Tokyo. Ten Czech companies took part.

One was Advanced Materials-JTJ, which produces photocatalytic coating materials incorporating titanium dioxide nanoparticles, known as FN coatings. The semi-transparent, odorless coatings have the unusual property of purifying the air around them — removing viruses, bacteria, toxins, cigarette smoke and more through a light-activated catalytic process.

Over the course of a year, “one square meter of FN-painted facade will clean and decontaminate over three million cubic meters of air,” or 106 million cubic feet, removing several kilograms of pollution, Mr. Prochazka [Jan Prochazka, Advanced Materials-JTJ’s chief executive] said.

As well as cleaning the air, the coating protects the painted surfaces from mold, fungus and the slow accumulation of dirt deposits that cause erosion and discoloring, he said.

The process, activated by ultraviolet light — that is, sunshine — is both environmentally friendly and cost-effective.

“For many people nano is a question mark, but really, everything is nano, except for gravel, sand and a few other materials,” Mr. Prochazka said in an interview in Prague. “Take a cup of water; you can’t imagine how many nanoparticles are inside.”

The National Information Centre For European Research (NICER) report titled, Czech Experience in the International Nanotechnology Cooperation, by Jitka Kubatova on the OECD website offers an overview of the public funding of R&D and much more,

the total (public + private) expenditure on R&D:

in 2005
42,2 billion CZK(€1,58 billion)
1,41% GDP (gross domestic product)

in 2006
49,9 billion CZK (€1,87 billion)
1,55% GDP

in 2007
54,3 billion CZK, (€2,03 billion)
1,53% GDP (p. 3 of the PDF)

Carbon nanotubes a second way: Cedric, the carbon nanotube computer

On the heels of yesterday’s(Sept. 26, 2013) posting about carbon nnanotubes as flexible gas sensors, I have this item about a computer fashioned from carbon nanotubes.

This wafer contains tiny computers using carbon nanotubes, a material that could lead to smaller, more energy-efficient processors. Courtesy Standford University

This wafer contains tiny computers using carbon nanotubes, a material that could lead to smaller, more energy-efficient processors. Courtesy Stanford University

To me this looks more like a ping pong bat than a computer wafer. Regardless, here’s more about it from a Sept. 25, 2013 news item by James Morgan for BBC (British Broadcasting Corporation) News online,

The first computer built entirely with carbon nanotubes has been unveiled, opening the door to a new generation of digital devices.

“Cedric” is only a basic prototype but could be developed into a machine which is smaller, faster and more efficient than today’s silicon models.

Nanotubes have long been touted as the heir to silicon’s throne, but building a working computer has proven awkward.

Cedric is the most complex carbon-based electronic system yet realised.

So is it fast? Not at all. It might have been in 1955.
The computer operates on just one bit of information, and can only count to 32.

“In human terms, Cedric can count on his hands and sort the alphabet. But he is, in the full sense of the word, a computer,” says co-author [of the paper published in Nature] Max Shulaker.

Tom Abate’s Sept. 26, 2013 article for Stanford Report provides more detail about carbon nanotubes, their potential for replacing silicon chips and associated problems,

“Carbon nanotubes [CNTs] have long been considered as a potential successor to the silicon transistor,” said Professor Jan Rabaey, a world expert on electronic circuits and systems at the University of California-Berkeley.

Why worry about a successor to silicon?

Such concerns arise from the demands that designers place upon semiconductors and their fundamental workhorse unit, those on-off switches known as transistors.

For decades, progress in electronics has meant shrinking the size of each transistor to pack more transistors on a chip. But as transistors become tinier, they waste more power and generate more heat – all in a smaller and smaller space, as evidenced by the warmth emanating from the bottom of a laptop.

Many researchers believe that this power-wasting phenomenon could spell the end of Moore’s Law, named for Intel Corp. co-founder Gordon Moore, who predicted in 1965 that the density of transistors would double roughly every two years, leading to smaller, faster and, as it turned out, cheaper electronics.

But smaller, faster and cheaper has also meant smaller, faster and hotter.

“CNTs could take us at least an order of magnitude in performance beyond where you can project silicon could take us,” Wong [another co-author of the paper]  said.

But inherent imperfections have stood in the way of putting this promising material to practical use.

First, CNTs do not necessarily grow in neat parallel lines, as chipmakers would like.

Over time, researchers have devised tricks to grow 99.5 percent of CNTs in straight lines. But with billions of nanotubes on a chip, even a tiny degree of misaligned tubes could cause errors, so that problem remained.

A second type of imperfection has also stymied CNT technology.

Depending on how the CNTs grow, a fraction of these carbon nanotubes can end up behaving like metallic wires that always conduct electricity, instead of acting like semiconductors that can be switched off.

Since mass production is the eventual goal, researchers had to find ways to deal with misaligned and/or metallic CNTs without having to hunt for them like needles in a haystack.

“We needed a way to design circuits without having to look for imperfections or even know where they were,” Mitra said.

The researchers have dubbed their solution an “imperfection-immune design,” from the Abate article,

To eliminate the wire-like or metallic nanotubes, the Stanford team switched off all the good CNTs. Then they pumped the semiconductor circuit full of electricity. All of that electricity concentrated in the metallic nanotubes, which grew so hot that they burned up and literally vaporized into tiny puffs of carbon dioxide. This sophisticated technique eliminated the metallic CNTs in the circuit.

Bypassing the misaligned nanotubes required even greater subtlety.

The Stanford researchers created a powerful algorithm that maps out a circuit layout that is guaranteed to work no matter whether or where CNTs might be askew.

“This ‘imperfections-immune design’ [technique] makes this discovery truly exemplary,” said Sankar Basu, a program director at the National Science Foundation.

The Stanford team used this imperfection-immune design to assemble a basic computer with 178 transistors, a limit imposed by the fact that they used the university’s chip-making facilities rather than an industrial fabrication process.

Their CNT computer performed tasks such as counting and number sorting. It runs a basic operating system that allows it to swap between these processes. In a demonstration of its potential, the researchers also showed that the CNT computer could run MIPS, a commercial instruction set developed in the early 1980s by then Stanford engineering professor and now university President John Hennessy.

Though it could take years to mature, the Stanford approach points toward the possibility of industrial-scale production of carbon nanotube semiconductors, according to Naresh Shanbhag, a professor at the University of Illinois at Urbana-Champaign and director of SONIC, a consortium of next-generation chip design research.

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

Carbon nanotube computer by Max M. Shulaker, Gage Hills, Nishant Patil, Hai Wei, Hong-Yu Chen, H.-S. Philip Wong, & Subhasish Mitra. Nature 501, 526–530 (26 September 2013) doi:10.1038/nature12502

This article is behind a paywall but you can gain temporary access via ReadCube.

Apply for Winter School at Center for Nanotechnology in Society at Arizona State University

The deadline to apply for Arizona State University’s Center for Nanotechnology in Society (CNS-ASU) Winter School  is Oct. 1, 2013 and thankfully the applications isn’t too onerous (a CV, a 500-word statement, and two references (names and contactinformation).

Here’s more about the school from the Aug. 27,2013 CNS-ASU call for applications,

CNS-ASU is an NSF funded center studying the societal implications of emerging technologies such as nanotechnology. The winter school is a week-long immersion into the research methods and tools used by CNS faculty and researchers.
The school is designed for graduate students, post-docs and junior faculty studying the societal questions surrounding emerging technologies and is a great opportunity to meet likeminded researchers, both domestic and international, along with many of our affiliated faculty from ASU, Georgia Tech and the University of Wisconsin – Madison.
The winter school takes place at Saguaro Lake Ranch, about an hour east of ASU’s Tempe campus. Participants are only expected to pay travel costs from their home institution. Local transportation and room and board are taken care of by CNS-ASU.

You can get more details about the school and about applying on the CNS-ASU Winter School 2014 webpage.

CNS-ASU Nanotechnology Winter School

Applications should be sent by email to with the subject: “Winter School.” Good luck!

OECD (Organization for Economic Cooperation and Development) makes recommendation regarding regulatory frameworks for nanomaterials.

A Sept. 26, 2013 news item on Nanowerk announces the latest OECD (Organization for Economic Cooperation and Development) recommendations on nanomaterial safety,

The OECD has recommended its Member Countries apply existing international and national chemical regulatory frameworks to manage the risks associated with manufactured nanomaterials.

The Sept. 20, 2013 OECD news release, which originated the news item, provides more details,

The Recommendation, approved by the Organisation’s governing Council, noted that these frameworks and other management systems may need to be adapted to take into account the specific properties of manufactured nanomaterials.

Manufactured nanomaterials are chemical particles that exhibit new characteristics in contrast to the same material without nanoscale features. These novel features offer possibilities for new commercial applications, such as solar cells using silicon nanocrystals to achieve higher efficiency. They also raise questions regarding potential unintended risks to humans and the environment. For example, new manufactured nanomaterials have applications in sunscreens and cosmetics, and so the potential risk from their exposure to consumers needs to be carefully assessed and managed.

The OECD has been working since 2006 to develop approaches for risk assessment for manufactured materials that are of high quality, science-based and internationally harmonised.

The Recommendation notes the importance of the OECD Test Guidelines for the Safety Testing of Chemicals, concluding that many of the existing guidelines are also suitable for the safety assessment of nanomaterials. At the same time, it recognises that some guidelines may need to be adapted to take into account the specific properties of nanomaterials. Work continues at OECD to achieve that.

An important consequence of this Recommendation is that much of the data collected as part of the safety assessment of nanomaterials will fall within the scope of the OECD system for the Mutual Acceptance of Data (MAD) in the Assessment of Chemicals. The OECD Mutual Acceptance of Data system is a multilateral agreement which saves governments and chemical producers around €150 million every year by allowing the results of a variety of non-clinical safety tests done on chemicals and chemical products, such as industrial chemicals and pesticides – and now nanomaterials – to be shared across OECD and other countries that adhere to the system.  Argentina, Brazil, India, Malaysia, Singapore, South Africa as well as all OECD countries are full adherents to the MAD system, and Thailand is a provisional adherent.

The extension of the scope of MAD to nanomaterials will considerably reduce the potential for non-tariff trade barriers between countries when marketing manufactured nanomaterials or products which include nanomaterials as well as allow for sharing the workload between countries in testing and assessing all the nanomaterials which are on the market. There will be a review of the Recommendation in three years to assess how it has been implemented in OECD countries and those partner countries which have adhered to it.

I find it odd the Working Party on Nanomaterialsis (or the Working Party on Manufacture Nanomaterials as it sometimes called) is not mentioned. This recommendation seems to have  arisen from the  Council on the Safety Testing and Assessment of Manufactured Nanomaterials. Canada is a member of the OECD and of its Working Party on Nanomaterials. I don’t know where we stand if anywhere on the Council on the Safety Testing and Assessment of Manufactured Nanomaterials. Perhaps I can check later when I have time.

Carbon nanotubes one way: gas The other way: flexible sensors*

A Sept. 24, 2013 Technische Universitaet Muenchen (TUM) press release (also on EurekAlert) promises that flexible sensors are on the horizon,

Carbon nanotube-based gas sensors created at TUM offer a unique combination of characteristics that can’t be matched by any of the alternative technologies. They rapidly detect and continuously respond to extremely small changes in the concentrations of gases including ammonia, carbon dioxide, and nitrogen oxide. They operate at room temperature and consume very little power. Furthermore, as the TUM researchers report in their latest papers, such devices can be fabricated on flexible backing materials through large-area, low-cost processes.

Thus it becomes realistic to envision plastic food wrap that incorporates flexible, disposable gas sensors, providing a more meaningful indicator of food freshness than the sell-by date. Measuring carbon dioxide, for example, can help predict the shelf life of meat. “Smart packaging” – assuming consumers find it acceptable and the devices’ non-toxic nature can be demonstrated – could enhance food safety and might also vastly reduce the amount of food that is wasted. Used in a different setting, the same sort of gas sensor could make it less expensive and more practical to monitor indoor air quality in real time.

Dexter Johnson in a Sept. 26, 2013 posting on Nanoclast (an IEEE [Institute of Electrical and Electronics Engineers] blog) warns (Note: Links have been removed),

While this sounds great, the obstacle preventing this from becoming a reality has always been cost. Thin-film sensory packaging may make sense for a high-cost item, but for an inexpensive grocery store product, it’s hard to justify an additional cost that may be as much as the product itself. I made this point nearly a decade ago in report I authored titled, “The Future of Nanotechnology in Printing and Packaging”.

This doesn’t even take into account the often biased opinion people have about nanotechnology in relation to food.

Dexter recommends the researchers focus their commercialization efforts on robotic skins and other high ticket applications.

In reading the description of how the researchers created these flexible sensors, Dexter’s concerns are brought int high relief,

The most basic building block for this technology is a single cylindrical molecule, a rolled-up sheet of carbon atoms that are linked in a honeycomb pattern. This so-called carbon nanotube could be likened to an unimaginably long garden hose: a hollow tube just a nanometer or so in diameter but perhaps millions of times as long as it is wide. Individual carbon nanotubes exhibit amazing and useful properties, but in this case the researchers are more interested in what can be done with them en masse.

Laid down in thin films, randomly oriented carbon nanotubes form conductive networks that can serve as electrodes; patterned and layered films can function as sensors or transistors. “In fact,” Prof. Lugli [Prof. Paolo Lugli, director of TUM’s Nanoelectronics Institute] explains, “the electrical resistivity of such films can be modulated by either an applied voltage (to provide a transistor action) or by the adsorption of gas molecules, which in turn is a signature of the gas concentration for sensor applications.” And as a basis for gas sensors in particular, carbon nanotubes combine advantages (and avoid shortcomings) of more established materials, such as polymer-based organic electronics and solid-state metal-oxide semiconductors. What has been lacking until now is a reliable, reproducible, low-cost fabrication method.

Spray deposition, supplemented if necessary by transfer printing, meets that need. An aqueous solution of carbon nanotubes looks like a bottle of black ink and can be handled in similar ways. Thus devices can be sprayed – from a computer-controlled robotic nozzle – onto virtually any kind of substrate, including large-area sheets of flexible plastic. There is no need for expensive clean-room facilities.

“To us it was important to develop an easily scalable technology platform for manufacturing large-area printed and flexible electronics based on organic semiconductors and nanomaterials,” Abdellah says. “To that end, spray deposition forms the core of our processing technology.”

Remaining technical challenges arise largely from application-specific requirements, such as the need for gas sensors to be selective as well as sensitive.

Here are citations for and links to three of the researchers’ papers,

Fabrication of carbon nanotube thin films on flexible substrates by spray deposition and transfer printing. Ahmed Abdelhalim, Alaa Abdellah, Giuseppe Scarpa, Paolo Lugli. Carbon, Vol. 61, September 2013, 72-79. DOI: 10.1016/j.carbon.2013.04.069

Flexible carbon nanotube-based gas sensors fabricated by large-scale spray deposition.
Alaa Abdellah, Zubair Ahmad, Philipp Köhler, Florin Loghin, Alexander Weise, Giuseppe Scarpa, Paolo Lugli. IEEE Sensors Journal, Vol. 13 Issue 10, October 2013, 4014-4021. DOI: 10.1109/JSEN.2013.2265775

Scalable spray deposition process for high performance carbon nanotube gas sensors. Alaa Abdellah, Ahmed Abdelhalim, Markus Horn, Giuseppe Scarpa, and Paolo Lugli. IEEE Transactions on Nanotechnology 12, 174-181, 2013. DOI: 10.1109/TNANO.2013.2238248

All three papers are behind paywalls.

In one of those coincidences that take place from time to time, I wrote about an upcoming event taking place in the Guardian’s London offices, a panel discussion on nanotechnology and food,in a Sept.  26, 2013 posting.

* In the interest of some clarity the head was changed on March 13, 2015.

UK’s Guardian newspaper hosts panel discussion: Should we use nanotechnology to feed ourselves?

This can be a short one. Should you happen to be in London, UK on Wednesday, Oct. 9, 2012, you can join in a panel discussion to be held in the Guardian’s offices (registration required). Here’s more from a Sept. 22, 2013 news item on Nanowerk,

Global society faces a number of stark choices regarding how we produce and consume food. Quite simply, current practices are not sustainable for the growing global population and trends observed in emerging economies of adopting a consumer-heavy Western lifestyle. We need to change.

This panel discussion, on Wednesday, October 9, 2013 at 6 pm, chaired by The Guardian’s Science and Environment Correspondent, Alok Jha, will discuss the contribution nanotechnologies can make to this, and the potential benefits and risks that go hand-in-hand.

Full details can be found here on the event registration page on the Guardian website,

The Guardian, in association with the Nanopinion Project, are delighted to offer readers the chance to attend an evening seminar on Wednesday 9 October, held at the Guardian offices in London.

There will be a panel discussion, chaired by the Guardian’s Science and Environment Correspondent, Alok Jha, to consider the contribution nanotechnologies can make to food production and security, and the potential benefits and risks that go hand-in-hand.

The discussion will reflect on the societal impacts that new technology solutions may have and will include representatives from industry, academia, NGOs and government agencies.

We will be discussing:

• Where are nanotechnologies are being used in the food chain?

• What can we expect in the future?

• What scenarios are likely from using or not using nanotechnologies?

• What are the alternatives?

• How are things different around the globe?

• What are the impacts of different nanomaterials on the environment?

• What about consumer confidence – who has looked at this?

The discussion will then be followed by a Q&A where delegates will have the opportunity to gain further insight from our panel of experts. The seminar will be reported through the Guardian’s online channels to encourage continued discussion and awareness of the key issues among the broader public.

Simply register your details below and you could win one of 20 places to this stimulating event.

Good luck and for those who can’t be bothered to scroll up,  here’s the registration page again. One final thought, it would be nice to know who their experts will be.