Tag Archives: Dexter Johnson

Carbon nanotube commercialization report from the US National Nanotechnology Initiative

Apparently a workshop on the topic commercializing carbon nanotubes was held in Washington, DC. in Sept. 2014. A March 12, 2015 news item on Nanowerk (originated by  March 12, 2015 US National Nanotechnology Initiative news release on EurekAlert) announces the outcome of that workshop (Note: Links have been removed),

The National Nanotechnology Initiative today published the proceedings of a technical interchange meeting on “Realizing the Promise of Carbon Nanotubes: Challenges, Opportunities, and the Pathway to Commercialization” (pdf), held at the National Aeronautics and Space Administration (NASA) Headquarters on September 15, 2014. This meeting brought together some of the Nation’s leading experts in carbon nanotube materials to identify, discuss, and report on technical barriers to the production of carbon nanotube (CNT)-based bulk and composite materials with properties that more closely match those of individual CNTs and to explore ways to overcome these barriers.

The outcomes of this meeting, as detailed in this report, will help inform the future directions of the NNI Nanotechnology Signature Initiative “Sustainable Nanomanufacturing: Creating the Industries of the Future”, which was launched in 2010 to accelerate the development of industrial-scale methods for manufacturing functional nanoscale systems.

The Technical Interchange Proceedings ‘Realizing the Promise of Carbon Nanotubes: Challenges, Opportunities, and the Pathway to Commercialization‘ (30 pp. PDF) describes areas for improvement in its executive summary,

A number of common themes and areas requiring focused attention were identified:

● Increased efforts devoted to manufacturing, quality control, and scale-up are needed. The development of a robust supply of CNT bulk materials with well-controlled properties would greatly enhance commercialization and spur use in a broad range of applications.
● Improvements are needed in the mechanical and electrical properties of CNT-based bulk materials (composites, sheets, and fibers) to approach the properties of individual CNTs. The development of bulk materials with properties nearing ideal CNT values would accelerate widespread adoption of these materials.
● More effective use of simulation and modeling is needed to provide insight into the fundamentals of the CNT growth process. Theoretical insight into the fundamentals of the growth process will inform the development of processes capable of producing high-quality material in quantity.
● Work is needed to help develop an understanding of the properties of bulk CNT-containing materials at longer length scales. Longer length scale understanding will enable the development of predictive models of structure–process–properties relationships and structural design technology tailored to take advantage of CNT properties.
● Standard materials and protocols are needed to guide the testing of CNT-based products for commercial applications. Advances in measurement methods are also required to characterize bulk CNT material properties and to understand the mechanism(s) of failure to help ensure material reliability.
● Life cycle assessments are needed for gauging commercial readiness. Life cycle assessments should include energy usage, performance lifetime, and degradation or disposal of CNT-based products.
● Collaboration to leverage resources and expertise is needed to advance commercialization of CNT-based products. Coordinated, focused efforts across academia, government laboratories, and industry to target grand challenges with support from public–private partnerships would accelerate efforts to provide solutions to overcome these technical barriers.

This meeting identified a number of the technical barriers that need to be overcome to make the promise of carbon nanotubes a reality. A more concerted effort is needed to focus R&D activities towards addressing these barriers and accelerating commercialization. The outcomes from this meeting will inform the future directions of the NNI Nanomanufacturing Signature Initiative and provide specific areas that warrant broader focus in the CNT research community. [p. vii print; p. 9 PDF]

This report, in its final section, explains the basis for the interest in and the hopes for carbon nanotubes,

Improving the electrical and mechanical properties of bulk carbon nanotube materials (yarns, fibers, wires, sheets, and composites) to more closely match those of individual carbon nanotubes will enable a revolution in materials that will have a broad impact on U.S. industries, global competitiveness, and the environment. Use of composites reinforced with high-strength carbon nanotube fibers in terrestrial and air transportation vehicles could enable a 25% reduction in their overall weight, reduce U.S. oil consumption by nearly 6 million barrels per day by 2035 [42], and reduce worldwide consumption of petroleum and other liquid fuels by 25%. This would result in the reduction of CO2 emissions by as much as 3.75 billion metric tons per year. Use of carbon nanotube-based data and power cables would lead to further reductions in vehicle weight, fuel consumption, and CO2 emissions. For example, replacement of the copper wiring in a Boeing 777 with CNT data and power cables that are 50% lighter would enable a 2,000-pound reduction in airplane weight. Use of carbon nanotube wiring in power distribution lines would reduce transmission losses by approximately 41 billion kilowatt hours annually [42], leading to significant savings in coal and gas consumption and reductions in the electric power industry’s carbon footprint.

The impact of developing these materials on U.S. global competitiveness is also significant. For example, global demand for carbon fibers is expected to grow from 46,000 metric tons per year in 2011 to more than 153,000 metric tons in 2020 due to the exponential growth in the use of composites in commercial aircraft, automobiles, aerospace, and wind energy [43]. Ultrahigh-strength CNT fibers would be highly attractive in each of these applications because they offer the advantage of reduced weight and improved performance over conventional carbon fibers. [p. 10 print; p. 20 PDF]

As these things go, this is a very short document, which makes it a fast read, and it has a reference list, something I always find useful.

My colleague, Dexter Johnson in a March 17, 2015 posting on his Nanoclast blog (on the IEEE [Institute for Electrical and Electronics Engineers] website) provides some background information before launching into an analysis of the report’s recommendations (Note: Links have been removed),

In the last half-a-decade we have witnessed once-beloved carbon nanotubes (CNTs) slowly being eclipsed by graphene as the “wonder material” of the nanomaterial universe.

This changing of the guard has occurred primarily within the research community, where the amount of papers being published about graphene seems to be steadily increasing. But in terms of commercial development, CNTs still have a leg up on graphene, finding increasing use in creating light but strong composites. Nonetheless, the commercial prospects for CNTs have been taking hits recently, with some producers scaling down capacity because of lack of demand.

With this as the backdrop, the National Nanotechnology Initiative (NNI), famous for its estimate back in 2001 that the market for nanotechnology will be worth $1 trillion by 2015,  has released a report based on a meeting held last September. …

I recommend reading Dexter’s analysis.

Dunkin’ Donuts and nano titanium dioxide

It’s been a busy few days for titanium dioxide, nano and otherwise, as the news about its removal from powdered sugar in Dunkin’ Donuts products ripples through the nano blogosphere. A March 6, 2015 news item on Azonano kicks off the discussion with an announcement,

Dunkin’ Brands, the parent company of the Dunkin’ Donuts chain, has agreed to remove titanium dioxide, a whitening agent that is commonly a source of nanomaterials, from all powdered sugar used to make the company’s donuts. As a result of this progress, the advocacy group As You Sow has withdrawn a shareholder proposal asking Dunkin’ to assess and reduce the risks of using nanomaterials in its food products.

Here’s a brief recent history of Dunkin’ Donuts and nano titanium dioxide from my Aug. 21, 2014 posting titled, FOE, nano, and food: part two of three (the problem with research),

Returning to the ‘debate’, a July 11, 2014 article by Sarah Shemkus for a sponsored section in the UK’s Guardian newspaper highlights an initiative taken by an environmental organization, As You Sow, concerning titanium dioxide in Dunkin’ Donuts’ products (Note: A link has been removed),

The activists at environmental nonprofit As You Sow want you to take another look at your breakfast doughnut. The organization recently filed a shareholder resolution asking Dunkin’ Brands, the parent company of Dunkin’ Donuts, to identify products that may contain nanomaterials and to prepare a report assessing the risks of using these substances in foods.

Their resolution received a fair amount of support: at the company’s annual general meeting in May, 18.7% of shareholders, representing $547m in investment, voted for it. Danielle Fugere, As You Sow’s president, claims that it was the first such resolution to ever receive a vote. Though it did not pass, she says that she is encouraged by the support it received.

“That’s a substantial number of votes in favor, especially for a first-time resolution,” she says.

The measure was driven by recent testing sponsored by As You Sow, which found nanoparticles of titanium dioxide in the powdered sugar that coats some of the donut chain’s products. [emphasis mine] An additive widely used to boost whiteness in products from toothpaste to plastic, microscopic titanium dioxide has not been conclusively proven unsafe for human consumption. Then again, As You Sow contends, there also isn’t proof that it is harmless.

“Until a company can demonstrate the use of nanomaterials is safe, we’re asking companies either to not use them or to provide labels,” says Fugere. “It would make more sense to understand these materials before putting them in our food.”

As I understand it, Dunkin’ Donuts will be removing all titanium dioxide, nano-sized or other, from powdered sugar used in its products. It seems As You Sow’s promise to withdraw its July 2104 shareholder resolution is the main reason for Dunkin’ Donuts’ decision. While I was and am critical of Dunkin’ Donuts’ handling of the situation with As You Sow, I am somewhat distressed that the company seems to have acquiesced on the basis of research which is, at best, inconclusive.

Dr. Andrew Maynard, director of the University of Michigan Risk Science Centre, has written a substantive analysis of the current situation regarding nano titanium dioxide in a March 12, 2015 post on his 2020 Science blog (Note: Links have been removed),

Titanium dioxide (which isn’t the same thing as the metal titanium) is an inert, insoluble material that’s used as a whitener in everything from paper and paint to plastics. It’s the active ingredient in many mineral-based sunscreens. And as a pigment, is also used to make food products look more appealing.

Part of the appeal to food producers is that titanium dioxide is a pretty dull chemical. It doesn’t dissolve in water. It isn’t particularly reactive. It isn’t easily absorbed into the body from food. And it doesn’t seem to cause adverse health problems. It just seems to do what manufacturers want it to do – make food look better. It’s what makes the powdered sugar coating on donuts appear so dense and snow white. Titanium dioxide gives it a boost.

And you’ve probably been consuming it for years without knowing. In the US, the Food and Drug Administration allows food products to contain up to 1% food-grade titanium dioxide without the need to include it on the ingredient label. Help yourself to a slice of bread, a bar of chocolate, a spoonful of mayonnaise or a donut, and chances are you’ll be eating a small amount of the substance.

Andrew goes on to describe the concerns that groups such as You As Sow have (Note: Links have been removed),

For some years now, researchers have recognized that some powders become more toxic the smaller the individual particles are, and titanium dioxide is no exception. Pigment grade titanium dioxide – the stuff typically used in consumer products and food – contains particles around 200 nanometers in diameter, or around one five hundredth the width of a human hair. Inhale large quantities of these titanium dioxide particles (I’m thinking “can’t see your hand in front of your face” quantities), and your lungs would begin to feel it.

If the particles are smaller though, it takes much less material to cause the same effect.

But you’d still need to inhale very large quantities of the material for it to be harmful. And while eating a powdered donut can certainly be messy, it’s highly unlikely that you’re going to end up stuck in a cloud of titanium dioxide-tinted powdered sugar coating!

… Depending on what they are made of and what shape they are, research has shown that some nanoparticles are capable of getting to parts of the body that are inaccessible to larger particles. And some particles are more chemically reactive because of their small size. Some may cause unexpected harm simply because they are small enough to throw a nano-wrench into the nano-workings of your cells.

This body of research is why organizations like As You Sow have been advocating caution in using nanoparticles in products without appropriate testing – especially in food. But the science about nanoparticles isn’t as straightforward as it seems.

As Andrew notes,

First of all, particles of the same size but made of different materials can behave in radically different ways. Assuming one type of nanoparticle is potentially harmful because of what another type does is the equivalent of avoiding apples because you’re allergic to oysters.

He describes some of the research on nano titanium dioxide (Note: Links have been removed),

… In 2004 the European Food Safety Agency carried out a comprehensive safety review of the material. After considering the available evidence on the same materials that are currently being used in products like Dunkin’ Donuts, the review panel concluded that there no evidence for safety concerns.

Most research on titanium dioxide nanoparticles has been carried out on ones that are inhaled, not ones we eat. Yet nanoparticles in the gut are a very different proposition to those that are breathed in.

Studies into the impacts of ingested nanoparticles are still in their infancy, and more research is definitely needed. Early indications are that the gastrointestinal tract is pretty good at handling small quantities of these fine particles. This stands to reason given the naturally occurring nanoparticles we inadvertently eat every day, from charred foods and soil residue on veggies and salad, to more esoteric products such as clay-baked potatoes. There’s even evidence that nanoparticles occur naturally inside the gastrointestinal tract.

He also probes the issue’s, nanoparticles, be they titanium dioxide or otherwise, and toxicity, complexity (Note: Links have been removed),

There’s a small possibility that we haven’t been looking in the right places when it comes to possible health issues. Maybe – just maybe – there could be long term health problems from this seemingly ubiquitous diet of small, insoluble particles that we just haven’t spotted yet. It’s the sort of question that scientists love to ask, because it opens up new avenues of research. It doesn’t mean that there is an issue, just that there is sufficient wiggle room in what we don’t know to ask interesting questions.

… While there is no evidence of a causal association between titanium dioxide in food and ill health, some studies – but not all by any means – suggest that large quantities of titanium dioxide nanoparticles can cause harm if they get to specific parts of the body.

For instance, there are a growing number of published studies that indicate nanometer sized titanium dioxide particles may cause DNA damage at high concentrations if it can get into cells. But while these studies demonstrate the potential for harm to occur, they lack information on how much material is needed, and under what conditions, for significant harm. And they tend to be associated with much larger quantities of material than anyone is likely to be ingesting on a regular basis.

They are also counterbalanced by studies that show no effects, indicating that there is still considerable uncertainty over the toxicity or otherwise of the material. It’s as if we’ve just discovered that paper can cause cuts, but we’re not sure yet whether this is a minor inconvenience or potentially life threatening. In the case of nanoscale titanium dioxide, it’s the classic case of “more research is needed.”

I strongly suggest reading Andrew’s post in its entirety either here on the University of Michigan website or here on The Conversation website.

Dexter Johnson in a March 11, 2015 post on his Nanoclast blog also weighs in on the discussion. He provides a very neat summary of the issues along with these observations (Note Links have been removed),

With decades of TiO2 being in our food supply and no reports of toxic reactions, it would seem that the threshold for proof is extremely high, especially when you combine the term “nano” with “asbestos”.

As You Sow makes sure to point out that asbestos is a nanoparticle. While the average diameter of an asbestos fiber is around 20 to 90 nm, their lengths varied between 200 nm and 200 micrometers.

The toxic aspect of asbestos was not its diameter, but its length. …

In addition to his summary Dexter highlights As You Sows attempt to link titanium dioxide nanoparticles to asbestos. I suggest reading his post for an informed description of what made asbestos so toxic (here) and why the linkage seems specious at this time.

For anyone interested in how As You Sow managed to introduce asbestos toxicity issues into a discussion about nano titanium dioxide and food products, there’s this from As You Sow’s FAQs (frequently asked questions) about nanomaterials in food page,

Why are nanomaterials in food important to investors?

When technology is used before ensuring that it is safe for humans and the environment, and before regulatory standards exist, companies can be exposed to significant financial, legal, and reputational risk. The limited studies that exist on nanomaterials, including nanoscale titanium dioxide*, have indicated that ingestion of these particles may pose health hazards.

The inaction of regulators does not protect companies, especially when the regulators themselves warn of the dangers of nanoparticles’ largely unknown risks. Draft guidance issued by the U.S. Food and Drug Administration raises questions about the safety of nanoparticles and demonstrates the general lack of knowledge about the technology and its effects. (1)

Asbestos litigation is a good example of the risks that can arise from using an emerging technology before it is proven safe. Use of asbestos (a nanomaterial) has created the longest, most expensive mass tort in national history with total U.S. costs now standing at over $250 billion. (2) If companies been asked to investigate and minimize or avoid risks prior to adopting asbestos technology, a sad and expensive chapter in worker harm could have been avoided.

* Titanium dioxide is a common pigment and FDA-approved food additive. It is used as a whitener, a dispersant, and a thickener.

While I don’t particularly appreciate fear-mongering as a tactic, the strategy of targeting investors and their concerns, seems to have helped As You Sow win its way.

Crumpling graphene to create a 3D structure and reflattening it afterwards

The reseaarchers at the University of Illinois College of Engineering are quite excited about a new technique for crumpling graphene as a Feb. 17, 2015 news item on ScienceDaily reports,

Researchers at the University of Illinois at Urbana-Champaign have developed a unique single-step process to achieve three-dimensional (3D) texturing of graphene and graphite. Using a commercially available thermally activated shape-memory polymer substrate, this 3D texturing, or “crumpling,” allows for increased surface area and opens the doors to expanded capabilities for electronics and biomaterials.

“Fundamentally, intrinsic strains on crumpled graphene could allow modulation of electrical and optical properties of graphene,” explained SungWoo Nam, an assistant professor of mechanical science and engineering at Illinois. “We believe that the crumpled graphene surfaces can be used as higher surface area electrodes for battery and supercapacitor applications. As a coating layer, 3D textured/crumpled nano-topographies could allow omniphobic/anti-bacterial surfaces for advanced coating applications.”

A Feb. 16, 2015 University of Illinois College of Engineering news release (also on EurekAlert), which originated the news item, describes the nature of graphene and what makes this technique so exciting,

Graphene—a single atomic layer of sp2-bonded carbon atoms—has been a material of intensive research and interest over recent years.  A combination of exceptional mechanical properties, high carrier mobility, thermal conductivity, and chemical inertness, make graphene a prime candidate material for next generation optoelectronic, electromechanical, and biomedical applications.

“In this study, we developed a novel method for controlled crumpling of graphene and graphite via heat-induced contractile deformation of the underlying substrate,” explained Michael Cai Wang, a graduate student and first author of the paper, “Heterogeneous, Three-Dimensional Texturing of Graphene,” which appeared in the journal Nano Letters. ”While graphene intrinsically exhibits tiny ripples in ambient conditions, we created large and tunable crumpled textures in a tailored and scalable fashion.”

“As a simpler, more scalable, and spatially selective method, this texturing of graphene and graphite exploits the thermally induced transformation of shape-memory thermoplastics, which has been previously applied to microfluidic device fabrication, metallic  film patterning, nanowire assembly, and robotic self-assembly applications,” added Nam, whose group has filed a patent for their novel strategy. “The thermoplastic nature of the polymeric substrate also allows for the crumpled graphene morphology to be arbitrarily re-flattened at the same elevated temperature for the crumpling process.”

“Due to the extremely low cost and ease of processing of our approach, we believe that this will be a new way to manufacture nanoscale topographies for graphene and many other 2D and thin-film materials.”

The researchers are also investigating the textured graphene surfaces for 3D sensor applications.

“Enhanced surface area will allow even more sensitive and intimate interactions with biological systems, leading to high sensitivity devices,” Nam said.

The funding agencies for this project were unexpectedly interesting (to me), from the news release,

Funding for this research was provided through the Air Force Office for Scientific Research, American Chemical Society and Brain Research Foundation. [emphasis mine] In addition to Wang, co-authors from Nam’s research group at Illinois include SungGyu Chun, Ryan Han, Ali Ashraf, and Pilgyu Kang.

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

Heterogeneous, Three-Dimensional Texturing of Graphene by Michael Cai Wang, SungGyu Chun, Ryan Steven Han, Ali Ashraf, Pilgyu Kang, and SungWoo Nam. Nano Lett., Article ASAP
DOI: 10.1021/nl504612y Publication Date (Web): February 10, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

Dexter Johnson has written a Feb. 20, 2015 post highlighting this work on his Nanoclast blog (on the Institute of Electrical and Electronics Engineers [IEEE] website).

FrogHeart and 2014: acknowledging active colleagues and saying good-bye to defunct blogs and hello to the new

It’s been quite the year. In Feb. 2014, TED offered me free livestreaming of the event in Vancouver. In March/April 2014, Google tweaked its search function and sometime in September 2014 I decided to publish two pieces per day rather than three with the consequence that the visit numbers for this blog are lower than they might otherwise have been. More about statistics and traffic to this blog will be in the post I usually publish just the new year has started.

On other fronts, I taught two courses (Bioelectronics and Nanotechnology, the next big idea) this year for Simon Fraser University (Vancouver, Canada) in its Continuing Studies (aka Lifelong Learning) programmes. I also attended a World Congress on Alternatives to Animal Testing in the Life Sciences in Prague. The trip, sponsored by SEURAT-1 (Safety Evaluation Ultimately Replacing Animal Testing), will result in a total of five stories, the first having been recently (Dec. 26, 2014) published. I’m currently preparing a submission for the International Symposium on Electronic Arts being held in Vancouver in August 2015 based on a project I have embarked upon, ‘Steep’. Focused on gold nanoparticles, the project is Raewyn Turner‘s (an artist from New Zealand) brainchild. She has kindly opened up the project in such a way that I too can contribute. There are two other members of the Steep project, Brian Harris, an electrical designer, who works closely with Raewyn on a number of arts projects and there’s Mark Wiesner as our science consultant. Wiesner is a professor of civil and environmental engineering,at Duke University in North Carolina.

There is one other thing which you may have noticed, I placed a ‘Donate’ button on the blog early in 2014.

Acknowledgements, good-byes, and hellos

Dexter Johnson on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website) remains a constant in the nano sector of the blogosphere where he provides his incisive opinions and context for the nano scene.

David Bruggeman on his Pasco Phronesis blog offers valuable insight into the US science policy scene along with a lively calendar of art/science events and an accounting of the science and technology guests on late night US television.

Andrew Maynard archived his 2020 Science blog in July 2014 but he does continue writing and communication science as director of the University of Michigan Risk Science Center. Notably, Andrew continues to write, along with other contributors, on the Risk Without Borders blog at the University of Michigan.

Sadly, Cientifica, a emerging technologies business consultancy, where Tim Harper published a number of valuable white papers, reports, and blog postings is no longer with us. Happily, Tim continues with an eponymous website where he blogs and communicates about various business interests, “I’m currently involved in graphene, nanotechnology, construction, heating, and biosensing, working for a UK public company, as well as organisations ranging from MIT [Massachusetts Institute of Technology] to the World Economic Forum.” Glad to you’re back to blogging Tim. I missed your business savvy approach and occasional cheekiness!

I was delighted to learn of a new nano blog, NanoScéal, this year and relieved to see they’re hanging in. Their approach is curatorial where they present a week of selected nano stories. I don’t think a lot of people realize how much work a curatorial approach requires. Bravo!

Sir Martyn Poliakoff and the Periodic Table of Videos

Just as I was wondering what happened to the Periodic Table of Videos (my April 25, 2011 post offers a description of the project) Grrl Scientist on the Guardian science blog network offers information about one of the moving forces behind the project, Martyn Poliakoff in a Dec. 31, 2014 post,

This morning [Dec. 31, 2014], I was most pleased to learn that Martyn Poliakoff, professor of chemistry at the University of Nottingham, was awarded a bachelor knighthood by the Queen. So pleased was I that I struggled out of bed (badly wrecked back), my teeth gritted, so I could share this news with you.

Now Professor Poliakoff — who now is more properly known as Professor SIR Martyn Poliakoff — was awarded one of the highest civilian honours in the land, and his continued online presence has played a significant role in this.

“I think it may be the first time that YouTube has been mentioned when somebody has got a knighthood, and so I feel really quite proud about that. And I also really want to thank you YouTube viewers who have made this possible through your enthusiasm for chemistry.”

As for the Periodic Table of Videos, the series continues past the 118 elements currently identified to a include discussions on molecules.

Science Borealis, the Canadian science blog aggregator, which I helped to organize (albeit desultorily), celebrated its first full year of operation. Congratulations to all those who worked to make this project such a success that it welcomed its 100th blog earlier this year. From a Sept. 24, 2014 news item on Yahoo (Note: Links have been removed),

This week the Science Borealis team celebrated the addition of the 100th blog to its roster of Canadian science blog sites! As was recently noted in the Council of Canadian Academies report on Science Culture, science blogging in Canada is a rapidly growing means of science communication. Our digital milestone is one of many initiatives that are bringing to fruition the vision of a rich Canadian online science communication community.

The honour of being syndicated as the 100th blog goes to Spider Bytes, by Catherine Scott, an MSc [Master of Science] student at Simon Fraser University in Burnaby, British Columbia. …

As always, it’s been a pleasure and privilege writing and publishing this blog. Thank you all for your support whether it comes in the form of reading it, commenting, tweeting,  subscribing, and/or deciding to publish your own blog. May you have a wonderful and rewarding 2015!

Projecting beams of light from contact lenses courtesy of Princeton University (US)

Princeton University’s 3D printed contact lenses with LED (light-emitting diodes) included are not meant for use by humans or other living beings but they are a flashy demonstration. From a Dec. 10, 2014 news item on phys.org,

As part of a project demonstrating new 3-D printing techniques, Princeton researchers have embedded tiny light-emitting diodes into a standard contact lens, allowing the device to project beams of colored light.

Michael McAlpine, the lead researcher, cautioned that the lens is not designed for actual use—for one, it requires an external power supply. Instead, he said the team created the device to demonstrate the ability to “3-D print” electronics into complex shapes and materials.

“This shows that we can use 3-D printing to create complex electronics including semiconductors,” said McAlpine, an assistant professor of mechanical and aerospace engineering. “We were able to 3-D print an entire device, in this case an LED.”

A Dec. 9, 2014 Princeton University news release by John Sullivan, which originated the news item, describes the 3D lens, the objectives for this project, and an earlier project involving a ‘bionic ear’ in more detail (Note: Links have been removed),

The hard contact lens is made of plastic. The researchers used tiny crystals, called quantum dots, to create the LEDs that generated the colored light. Different size dots can be used to generate various colors.

“We used the quantum dots [also known as nanoparticles] as an ink,” McAlpine said. “We were able to generate two different colors, orange and green.”

The contact lens is also part of an ongoing effort to use 3-D printing to assemble diverse, and often hard-to-combine, materials into functioning devices. In the recent past, a team of Princeton professors including McAlpine created a bionic ear out of living cells with an embedded antenna that could receive radio signals.

Yong Lin Kong, a researcher on both projects, said the bionic ear presented a different type of challenge.

“The main focus of the bionic ear project was to demonstrate the merger of electronics and biological materials,” said Kong, a graduate student in mechanical and aerospace engineering.

Kong, the lead author of the Oct. 31 [2014] article describing the current work in the journal Nano Letters, said that the contact lens project, on the other hand, involved the printing of active electronics using diverse materials. The materials were often mechanically, chemically or thermally incompatible — for example, using heat to shape one material could inadvertently destroy another material in close proximity. The team had to find ways to handle these incompatibilities and also had to develop new methods to print electronics, rather than use the techniques commonly used in the electronics industry.

“For example, it is not trivial to pattern a thin and uniform coating of nanoparticles and polymers without the involvement of conventional microfabrication techniques, yet the thickness and uniformity of the printed films are two of the critical parameters that determine the performance and yield of the printed active device,” Kong said.

To solve these interdisciplinary challenges, the researchers collaborated with Ian Tamargo, who graduated this year with a bachelor’s degree in chemistry; Hyoungsoo Kim, a postdoctoral research associate and fluid dynamics expert in the mechanical and aerospace engineering department; and Barry Rand, an assistant professor of electrical engineering and the Andlinger Center for Energy and the Environment.

McAlpine said that one of 3-D printing’s greatest strengths is its ability to create electronics in complex forms. Unlike traditional electronics manufacturing, which builds circuits in flat assemblies and then stacks them into three dimensions, 3-D printers can create vertical structures as easily as horizontal ones.

“In this case, we had a cube of LEDs,” he said. “Some of the wiring was vertical and some was horizontal.”

To conduct the research, the team built a new type of 3-D printer that McAlpine described as “somewhere between off-the-shelf and really fancy.” Dan Steingart, an assistant professor of mechanical and aerospace engineering and the Andlinger Center, helped design and build the new printer, which McAlpine estimated cost in the neighborhood of $20,000.

McAlpine said that he does not envision 3-D printing replacing traditional manufacturing in electronics any time soon; instead, they are complementary technologies with very different strengths. Traditional manufacturing, which uses lithography to create electronic components, is a fast and efficient way to make multiple copies with a very high reliability. Manufacturers are using 3-D printing, which is slow but easy to change and customize, to create molds and patterns for rapid prototyping.

Prime uses for 3-D printing are situations that demand flexibility and that need to be tailored to a specific use. For example, conventional manufacturing techniques are not practical for medical devices that need to be fit to a patient’s particular shape or devices that require the blending of unusual materials in customized ways.

“Trying to print a cellphone is probably not the way to go,” McAlpine said. “It is customization that gives the power to 3-D printing.”

In this case, the researchers were able to custom 3-D print electronics on a contact lens by first scanning the lens, and feeding the geometric information back into the printer. This allowed for conformal 3-D printing of an LED on the contact lens.

Here’s what the contact lens looks like,

Michael McAlpine, an assistant professor of mechanical and aerospace engineering at Princeton, is leading a research team that uses 3-D printing to create complex electronics devices such as this light-emitting diode printed in a plastic contact lens. (Photos by Frank Wojciechowski)

Michael McAlpine, an assistant professor of mechanical and aerospace engineering at Princeton, is leading a research team that uses 3-D printing to create complex electronics devices such as this light-emitting diode printed in a plastic contact lens. (Photos by Frank Wojciechowski)

Also, here’s a link to and a citation for the research paper,

3D Printed Quantum Dot Light-Emitting Diodes by Yong Lin Kong, Ian A. Tamargo, Hyoungsoo Kim, Blake N. Johnson, Maneesh K. Gupta, Tae-Wook Koh, Huai-An Chin, Daniel A. Steingart, Barry P. Rand, and Michael C. McAlpine. Nano Lett., 2014, 14 (12), pp 7017–7023 DOI: 10.1021/nl5033292 Publication Date (Web): October 31, 2014

Copyright © 2014 American Chemical Society

This paper is behind a paywall.

I’m always a day behind for Dexter Johnson’s postings on the Nanoclast blog (located on the IEEE [institute of Electrical and Electronics Engineers]) so I didn’t see his Dec. 11, 2014 post about these 3Dprinted LED[embedded contact lenses until this morning (Dec. 12, 2014). In any event, I’m excerpting his very nice description of quantum dots,

The LED was made out of the somewhat exotic nanoparticles known as quantum dots. Quantum dots are a nanocrystal that have been fashioned out of semiconductor materials and possess distinct optoelectronic properties, most notably fluorescence, which makes them applicable in this case for the LEDs of the contact lens.

“We used the quantum dots [also known as nanoparticles] as an ink,” McAlpine said. “We were able to generate two different colors, orange and green.”

I encourage you to read Dexter’s post as he provides additional insights based on his long-standing membership within the nanotechnology community.

Graphene not so impermeable after all

I saw the news last week but it took reading Dexter Johnson’s Dec. 2, 2014 post for me to achieve a greater understanding of why graphene’s proton permeability is such a big deal and of the tensions underlying graphene research in the UK.

Let’s start with the news, from a Nov. 26, 2014 news item on Nanowerk (Note: A link has been removed),

Published in the journal Nature (“Proton transport through one-atom-thick crystals”), the discovery could revolutionise fuel cells and other hydrogen-based technologies as they require a barrier that only allow protons – hydrogen atoms stripped off their electrons – to pass through.

In addition, graphene membranes could be used to sieve hydrogen gas out of the atmosphere, where it is present in minute quantities, creating the possibility of electric generators powered by air.

A Nov. 26, 2014 University of Manchester news release, which originated the news item, describes the research in greater detail,

One-atom thick material graphene, first isolated and explored in 2004 by a team at The University of Manchester, is renowned for its barrier properties, which has a number of uses in applications such as corrosion-proof coatings and impermeable packaging.

For example, it would take the lifetime of the universe for hydrogen, the smallest of all atoms, to pierce a graphene monolayer.

Now a group led by Sir Andre Geim tested whether protons are also repelled by graphene. They fully expected that protons would be blocked, as existing theory predicted as little proton permeation as for hydrogen.

Despite the pessimistic prognosis, the researchers found that protons pass through the ultra-thin crystals surprisingly easily, especially at elevated temperatures and if the films were covered with catalytic nanoparticles such as platinum.

The discovery makes monolayers of graphene, and its sister material boron nitride, attractive for possible uses as proton-conducting membranes, which are at the heart of modern fuel cell technology. Fuel cells use oxygen and hydrogen as a fuel and convert the input chemical energy directly into electricity. Without membranes that allow an exclusive flow of protons but prevent other species to pass through, this technology would not exist.

Despite being well-established, fuel-cell technology requires further improvements to make it more widely used. One of the major problems is a fuel crossover through the existing proton membranes, which reduces their efficiency and durability.

The University of Manchester research suggests that the use of graphene or monolayer boron nitride can allow the existing membranes to become thinner and more efficient, with less fuel crossover and poisoning. This can boost competitiveness of fuel cells.

The Manchester group also demonstrated that their one-atom-thick membranes can be used to extract hydrogen from a humid atmosphere. They hypothesise that such harvesting can be combined together with fuel cells to create a mobile electric generator that is fuelled simply by hydrogen present in air.

Marcelo Lozada-Hidalgo, a PhD student and corresponding author of this paper, said: “When you know how it should work, it is a very simple setup. You put a hydrogen-containing gas on one side, apply small electric current and collect pure hydrogen on the other side. This hydrogen can then be burned in a fuel cell.

“We worked with small membranes, and the achieved flow of hydrogen is of course tiny so far. But this is the initial stage of discovery, and the paper is to make experts aware of the existing prospects. To build up and test hydrogen harvesters will require much further effort.”

Dr Sheng Hu, a postdoctoral researcher and the first author in this work, added: “It looks extremely simple and equally promising. Because graphene can be produced these days in square metre sheets, we hope that it will find its way to commercial fuel cells sooner rather than later”.

The work is an international collaboration involving groups from China and the Netherlands who supported theoretical aspects of this research. Marcelo Lozada-Hidalgo is funded by a PhD studentship programme between the National Council of Science and Technology of Mexico and The University of Manchester.

Here’s more about the research and its implications from Dexter Johnson’s Dec. 2, 2014 post on the Nanoclast blog on the IEEE (Institute of Electronics and Electrical Engineers) website (Note: Links have been removed),

This latest development alters the understanding of one of the key properties of graphene: that it is impermeable to all gases and liquids. Even an atom as small as hydrogen would need billions of years for it to pass through the dense electronic cloud of graphene.  In fact, it is this impermeability that has made it attractive for use in gas separation membranes.

But as Geim and his colleagues discovered, in research that was published in the journal Nature, monolayers of graphene and boron nitride are highly permeable to thermal protons under ambient conditions. So hydrogen atoms stripped of their electrons could pass right through the one-atom-thick materials.

The surprising discovery that protons could breach these materials means that that they could be used in proton-conducting membranes (also known as proton exchange membranes), which are central to the functioning of fuel cells. Fuel cells operate through chemical reactions involving hydrogen fuel and oxygen, with the result being electrical energy. The membranes used in the fuel cells are impermeable to oxygen and hydrogen but allow for the passage of protons.

Dexter goes into more detail about hydrogen fuel cells and why this discovery is so exciting. He also provides some insight into the UK’s graphene community (Note: A link has been removed),

While some have been frustrated that Geim has focused his attention on fundamental research rather than becoming more active in the commercialization of graphene, he may have just cracked open graphene’s greatest application possibility to date.

I recommend reading Dexter’s post if you want to learn more about fuel cell technology and the impact this discovery may have.

Richard Van Noorden’s Nov. 27, 2014 article for Nature provides another perspective on this work,

Fuel-cell experts say that the work is proof of principle, but are cautious about its immediate application. Factors such as to how grow a sufficiently clean, large graphene sheet, and its cost and lifetime, would have to be taken into account. “It may or may not be a better membrane for a fuel cell,” says Andrew Herring, a chemical engineer at the Colorado School of Mines in Golden.

Van Noorden also writes about another graphene discovery from last week, which won’t be featured here. Where graphene is concerned I have to draw a line or else this entire blog would be focused on that material alone.

Getting back back to permeability, graphene, and protons, here’s a link to and a citation for the research paper,

Proton transport through one-atom-thick crystals by S. Hu, M. Lozada-Hidalgo, F. C. Wang, A. Mishchenko, F. Schedin, R. R. Nair, E. W. Hill, D. W. Boukhvalov, M. I. Katsnelson, R. A. W. Dryfe, I. V. Grigorieva, H. A. Wu, & A. K. Geim. Nature (2014 doi:10.1038/nature14015 Published online 26 November 2014

This article is behind a paywall.

Super-capacitors on automobiles

Queensland University of Technology* (QUT; Australia) researchers are hopeful they can adapt supercapacitors in the form of a fine film tor use in electric vehicles making them more energy-efficient. From a Nov. 6, 2014 news item on ScienceDaily,

A car powered by its own body panels could soon be driving on our roads after a breakthrough in nanotechnology research by a QUT team.

Researchers have developed lightweight “supercapacitors” that can be combined with regular batteries to dramatically boost the power of an electric car.

The discovery was made by Postdoctoral Research Fellow Dr Jinzhang Liu, Professor Nunzio Motta and PhD researcher Marco Notarianni, from QUT’s Science and Engineering Faculty — Institute for Future Environments, and PhD researcher Francesca Mirri and Professor Matteo Pasquali, from Rice University in Houston, in the United States.

A Nov. 6, 2014 QUT news release, which originated the news item, describes supercapacitors, the research, and the need for this research in more detail,

The supercapacitors – a “sandwich” of electrolyte between two all-carbon electrodes – were made into a thin and extremely strong film with a high power density.

The film could be embedded in a car’s body panels, roof, doors, bonnet and floor – storing enough energy to turbocharge an electric car’s battery in just a few minutes.

“Vehicles need an extra energy spurt for acceleration, and this is where supercapacitors come in. They hold a limited amount of charge, but they are able to deliver it very quickly, making them the perfect complement to mass-storage batteries,” he said.

“Supercapacitors offer a high power output in a short time, meaning a faster acceleration rate of the car and a charging time of just a few minutes, compared to several hours for a standard electric car battery.”

Dr Liu said currently the “energy density” of a supercapacitor is lower than a standard lithium ion (Li-Ion) battery, but its “high power density”, or ability to release power in a short time, is “far beyond” a conventional battery.

“Supercapacitors are presently combined with standard Li-Ion batteries to power electric cars, with a substantial weight reduction and increase in performance,” he said.

“In the future, it is hoped the supercapacitor will be developed to store more energy than a Li-Ion battery while retaining the ability to release its energy up to 10 times faster – meaning the car could be entirely powered by the supercapacitors in its body panels.

“After one full charge this car should be able to run up to 500km – similar to a petrol-powered car and more than double the current limit of an electric car.”

Dr Liu said the technology would also potentially be used for rapid charges of other battery-powered devices.

“For example, by putting the film on the back of a smart phone to charge it extremely quickly,” he said.

The discovery may be a game-changer for the automotive industry, with significant impacts on financial, as well as environmental, factors.

“We are using cheap carbon materials to make supercapacitors and the price of industry scale production will be low,” Professor Motta said.

“The price of Li-Ion batteries cannot decrease a lot because the price of Lithium remains high. This technique does not rely on metals and other toxic materials either, so it is environmentally friendly if it needs to be disposed of.”

A Nov. 10, 2014 news item on Azonano describes the Rice University (Texas, US) contribution to this work,

Rice University scientist Matteo Pasquali and his team contributed to two new papers that suggest the nano-infused body of a car may someday power the car itself.

Rice supplied high-performance carbon nanotube films and input on the device design to scientists at the Queensland University of Technology in Australia for the creation of lightweight films containing supercapacitors that charge quickly and store energy. The inventors hope to use the films as part of composite car doors, fenders, roofs and other body panels to significantly boost the power of electric vehicles.

A Nov. 7, 2014 Rice University news release, which originated the news item, offers a few technical details about the film being proposed for use as a supercapacitor on car panels,

Researchers in the Queensland lab of scientist Nunzio Motta combined exfoliated graphene and entangled multiwalled carbon nanotubes combined with plastic, paper and a gelled electrolyte to produce the flexible, solid-state supercapacitors.

“Nunzio’s team is making important advances in the energy-storage area, and we were glad to see that our carbon nanotube film technology was able to provide breakthrough current collection capability to further improve their devices,” said Pasquali, a Rice professor of chemical and biomolecular engineering and chemistry. “This nice collaboration is definitely bottom-up, as one of Nunzio’s Ph.D. students, Marco Notarianni, spent a year in our lab during his Master of Science research period a few years ago.”

“We built on our earlier work on CNT films published in ACS Nano, where we developed a solution-based technique to produce carbon nanotube films for transparent electrodes in displays,” said Francesca Mirri, a graduate student in Pasquali’s research group and co-author of the papers. “Now we see that carbon nanotube films produced by the solution-processing method can be applied in several areas.”

As currently designed, the supercapacitors can be charged through regenerative braking and are intended to work alongside the lithium-ion batteries in electric vehicles, said co-author Notarianni, a Queensland graduate student.

“Vehicles need an extra energy spurt for acceleration, and this is where supercapacitors come in. They hold a limited amount of charge, but with their high power density, deliver it very quickly, making them the perfect complement to mass-storage batteries,” he said.

Because hundreds of film supercapacitors are used in the panel, the electric energy required to power the car’s battery can be stored in the car body. “Supercapacitors offer a high power output in a short time, meaning a faster acceleration rate of the car and a charging time of just a few minutes, compared with several hours for a standard electric car battery,” Notarianni said.

The researchers foresee such panels will eventually replace standard lithium-ion batteries. “In the future, it is hoped the supercapacitor will be developed to store more energy than an ionic battery while retaining the ability to release its energy up to 10 times faster – meaning the car would be powered by the supercapacitors in its body panels,” said Queensland postdoctoral researcher Jinzhang Liu.

Here’s an image of graphene infused with carbon nantoubes used in the supercapacitor film,

A scanning electron microscope image shows freestanding graphene film with carbon nanotubes attached. The material is part of a project to create lightweight films containing super capacitors that charge quickly and store energy. Courtesy of Nunzio Motta/Queensland University of Technology - See more at: http://news.rice.edu/2014/11/07/supercharged-panels-may-power-cars/#sthash.0RPsIbMY.dpuf

A scanning electron microscope image shows freestanding graphene film with carbon nanotubes attached. The material is part of a project to create lightweight films containing super capacitors that charge quickly and store energy. Courtesy of Nunzio Motta/Queensland University of Technology

Here are links to and citations for the two papers published by the researchers,

Graphene-based supercapacitor with carbon nanotube film as highly efficient current collector by Marco Notarianni, Jinzhang Liu, Francesca Mirri, Matteo Pasquali, and Nunzio Motta. Nanotechnology Volume 25 Number 43 doi:10.1088/0957-4484/25/43/435405

High performance all-carbon thin film supercapacitors by Jinzhang Liu, Francesca Mirri, Marco Notarianni, Matteo Pasquali, and Nunzio Motta. Journal of Power Sources Volume 274, 15 January 2015, Pages 823–830 DOI: 10.1016/j.jpowsour.2014.10.104

Both articles are behind paywalls.

One final note, Dexter Johnson provides some insight into issues with graphene-based supercapacitors and what makes this proposed application attractive in his Nov. 7, 2014 post on the Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website; Note: Links have been removed),

The hope has been that someone could make graphene electrodes for supercapacitors that would boost their energy density into the range of chemical-based batteries. The supercapacitors currently on the market have on average an energy density around 28 Wh/kg, whereas a Li-ion battery holds about 200Wh/kg. That’s a big gap to fill.

The research in the field thus far has indicated that graphene’s achievable surface area in real devices—the factor that determines how many ions a supercapacitor electrode can store, and therefore its energy density—is not any better than traditional activated carbon. In fact, it may not be much better than a used cigarette butt.

Though graphene may not help increase supercapacitors’ energy density, its usefulness in this application may lie in the fact that its natural high conductivity will allow superconductors to operate at higher frequencies than those that are currently on the market. Another likely benefit that graphene will yield comes from the fact that it can be structured and scaled down, unlike other supercapacitor materials.

I recommend reading Dexter’s commentary in its entirety.

*’University of Queensland’ corrected to “Queensland University of Technology’ on Nov. 10, 2014 at 1335 PST.

NASA, super-black nanotechnology, and an International Space Station livestreamed event

A super-black nanotechnology-enabled coating (first mentioned here in a July 18, 2013 posting featuring work by John Hagopian, an optics engineer at the US National Aeronautics and Space Administration [NASA’s] Goddard Space Flight Center on this project) is about to be tested in outer space. From an Oct. 23, 2014 news item on Nanowerk,

An emerging super-black nanotechnology that is to be tested for the first time this fall on the International Space Station will be applied to a complex, 3-D component critical for suppressing stray light in a new, smaller, less-expensive solar coronagraph designed to ultimately fly on the orbiting outpost or as a hosted payload on a commercial satellite.

The super-black carbon-nanotube coating, whose development is six years in the making, is a thin, highly uniform coating of multi-walled nanotubes made of pure carbon about 10,000 times thinner than a strand of human hair. Recently delivered to the International Space Station for testing, the coating is considered especially promising as a technology to reduce stray light, which can overwhelm faint signals that sensitive detectors are supposed to retrieve.

An Oct. 24, 2014 NASA news release by Lori Keesey, which originated the news item, further describes the work being done on the ground simultaneous to the tests on the International Space Station,

While the coating undergoes testing to determine its robustness in space, a team at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, will apply the carbon-nanotube coating to a complex, cylindrically shaped baffle — a component that helps reduce stray light in telescopes.

Goddard optical engineer Qian Gong designed the baffle for a compact solar coronagraph that Principal Investigator Nat Gopalswamy is now developing. The goal is [to] build a solar coronagraph that could deploy on the International Space Station or as a hosted payload on a commercial satellite — a much-needed capability that could guarantee the continuation of important space weather-related measurements.

The effort will help determine whether the carbon nanotubes are as effective as black paint, the current state-of-the-art technology, for absorbing stray light in complex space instruments and components.

Preventing errant light is an especially tricky challenge for Gopalswamy’s team. “We have to have the right optical system and the best baffles going,” said Doug Rabin, a Goddard heliophysicist who studies diffraction and stray light in coronagraphs.

The new compact coronagraph — designed to reduce the mass, volume, and cost of traditional coronagraphs by about 50 percent — will use a single set of lenses, rather than a conventional three-stage system, to image the solar corona, and more particularly, coronal mass ejections (CMEs). These powerful bursts of solar material erupt and hurdle across the solar system, sometimes colliding with Earth’s protective magnetosphere and posing significant hazards to spacecraft and astronauts.

“Compact coronagraphs make greater demands on controlling stray light and diffraction,” Rabin explained, adding that the corona is a million times fainter than the sun’s photosphere. Coating the baffle or occulter with the carbon-nanotube material should improve the component’s overall performance by preventing stray light from reaching the focal plane and contaminating measurements.

The project is well timed and much needed, Rabin added.

Currently, the heliophysics community receives coronagraphic measurements from the Solar and Heliospheric Observatory (SOHO) and the Solar Terrestrial Relations Observatory (STEREO).

“SOHO, which we launched in 1995, is one of our Great Observatories,” Rabin said. “But it won’t last forever.” Although somewhat newer, STEREO has operated in space since 2006. “If one of these systems fails, it will affect a lot of people inside and outside NASA, who study the sun and forecast space weather. Right now, we have no scheduled mission that will carry a solar coronagraph. We would like to get a compact coronagraph up there as soon as possible,” Rabin added.

Ground-based laboratory testing indicates it could be a good fit. Testing has proven that the coating absorbs 99.5 percent of the light in the ultraviolet and visible and 99.8 percent in the longer infrared bands due to the fact that the carbon atoms occupying the tiny nested tubes absorb the light and prevent it from reflecting off surfaces, said Goddard optics engineer John Hagopian, who is leading the technology’s advancement. Because only a tiny fraction of light reflects off the coating, the human eye and sensitive detectors see the material as black — in this case, extremely black.

“We’ve made great progress on the coating,” Hagopian said. “The fact the coatings have survived the trip to the space station already has raised the maturity of the technology to a level that qualifies them for flight use. In many ways the external exposure of the samples on the space station subjects them to a much harsher environment than components will ever see inside of an instrument.”

Given the need for a compact solar coronagraph, Hagopian said he’s especially excited about working with the instrument team. “This is an important instrument-development effort, and, of course, one that could showcase the effectiveness of our technology on 3-D parts,” he said, adding that the lion’s share of his work so far has concentrated on 2-D applications.

By teaming with Goddard technologist Vivek Dwivedi, Hagopian believes the baffle project now is within reach. Dwivedi is advancing a technique called atomic layer deposition (ALD) that lays down a catalyst layer necessary for carbon-nanotube growth on complex, 3-D parts. “Previous ALD chambers could only hold objects a few millimeters high, while the chamber Vivek has developed for us can accommodate objects 20 times bigger; a necessary step for baffles of this type,” Hagopian said.

Other NASA researchers have flown carbon nanotubes on the space station, but their samples were designed for structural applications, not stray-light suppression — a completely different use requiring that the material demonstrate greater absorption properties, Hagopian said.

“We have extreme stray light requirements. Let’s see how this turns out,” Rabin said.

The researchers from NASA have kindly made available an image of a baffle prior to receiving its super-black coating,

This is a close-up view of a baffle that will be coated with a carbon-nanotube coating. Image Credit:  NASA Goddard/Paul Nikulla

This is a close-up view of a baffle that will be coated with a carbon-nanotube coating.
Image Credit: NASA Goddard/Paul Nikulla

There’s more information about the project in this August 12, 2014 NASA news release first announcing the upcoming test.

Serendipitously or not, NASA is hosting an interactive Space Technology Forum on Oct. 27, 2014 (this coming Monday) focusing on technologies being demonstrated on the International Space Station (ISS) according to an Oct. 20, 2014 NASA media advisory,

Media are invited to interact with NASA experts who will answer questions about technologies being demonstrated on the International Space Station (ISS) during “Destination Station: ISS Technology Forum” from 10 to 11 a.m. EDT (9 to 10 a.m. CDT [7 to 8 am PDT]) Monday, Oct. 27, at the U.S. Space & Rocket Center in Huntsville, Alabama.

The forum will be broadcast live on NASA Television and the agency’s website.

The Destination Station forums are a series of live, interactive panel discussions about the space station. This is the second in the series, and it will feature a discussion on how technologies are tested aboard the orbiting laboratory. Thousands of investigations have been performed on the space station, and although they provide benefits to people on Earth, they also prepare NASA to send humans farther into the solar system than ever before.

Forum panelists and exhibits will focus on space station environmental and life support systems; 3-D printing; Space Communications and Navigation (SCaN) systems; and Synchronized Position Hold, Engage, Reorient, Experimental Satellites (SPHERES).

The forum’s panelists are:
– Jeffrey Sheehy, senior technologist in NASA’s Space Technology Mission Directorate
– Robyn Gatens, manager for space station System and Technology Demonstration, and Environmental Control Life Support System expert
– Jose Benavides, SPHERES chief engineer
– Rich Reinhart, principal investigator for the SCaN Testbed
– Niki Werkeiser, project manager for the space station 3-D printer

During the forum, questions will be taken from the audience, including media, students and social media participants. Online followers may submit questions via social media using the hashtag, #asknasa. [emphasis mine] …

The “Destination Station: ISS Technology Forum” coincides with the 7th Annual Von Braun Memorial Symposium at the University of Alabama in Huntsville Oct. 27-29. Media can attend the three-day symposium, which features NASA officials, including NASA Administrator Charles Bolden, Associate Administrator for Human Exploration and Operation William Gerstenmaier and Assistant Deputy Associate Administrator for Exploration Systems Development Bill Hill. Jean-Jacques Dordain, director general of the European Space Agency, will be a special guest speaker. Representatives from industry and academia also will be participating.

For NASA TV streaming video, scheduling and downlink information, visit:

http://www.nasa.gov/nasatv

For more information on the International Space Station and its crews, visit:

http://www.nasa.gov/station

I have checked out the livestreaming/tv site and it appears that registration is not required for access. Sadly, I don’t see any the ‘super-black’ coating team members mentioned in the news release on the list of forum participants.

ETA Oct. 27, 2014: You can check out Dexter Johnson’s Oct. 24, 2014 posting on the Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website for a little more information

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).

Next supercapacitor: crumpled graphene?

An Oct. 3, 2014 news item on ScienceDaily features the use of graphene as a possible supercapacitor,

When someone crumples a sheet of paper, that usually means it’s about to be thrown away. But researchers have now found that crumpling a piece of graphene “paper” — a material formed by bonding together layers of the two-dimensional form of carbon — can actually yield new properties that could be useful for creating extremely stretchable supercapacitors to store energy for flexible electronic devices.

The finding is reported in the journal Scientific Reports by MIT’s {Massachusetts Institute of Technology] Xuanhe Zhao, an assistant professor of mechanical engineering and civil and environmental engineering, and four other authors. The new, flexible superconductors should be easy and inexpensive to fabricate, the team says.

An Oct. 3, 2014 MIT news release by David Chandler (also on EurekAlert), which originated the news item, explains the technology at more length,

“Many people are exploring graphene paper: It’s a good candidate for making supercapacitors, because of its large surface area per mass,” Zhao says. Now, he says, the development of flexible electronic devices, such as wearable or implantable biomedical sensors or monitoring devices, will require flexible power-storage systems.

Like batteries, supercapacitors can store electrical energy, but they primarily do so electrostatically, rather than chemically — meaning they can deliver their energy faster than batteries can. Now Zhao and his team have demonstrated that by crumpling a sheet of graphene paper into a chaotic mass of folds, they can make a supercapacitor that can easily be bent, folded, or stretched to as much as 800 percent of its original size. The team has made a simple supercapacitor using this method as a proof of principle.

The material can be crumpled and flattened up to 1,000 times, the team has demonstrated, without a significant loss of performance. “The graphene paper is pretty robust,” Zhao says, “and we can achieve very large deformations over multiple cycles.” Graphene, a structure of pure carbon just one atom thick with its carbon atoms arranged in a hexagonal array, is one of the strongest materials known.

To make the crumpled graphene paper, a sheet of the material was placed in a mechanical device that first compressed it in one direction, creating a series of parallel folds or pleats, and then in the other direction, leading to a chaotic, rumpled surface. When stretched, the material’s folds simply smooth themselves out.

Forming a capacitor requires two conductive layers — in this case, two sheets of crumpled graphene paper — with an insulating layer in between, which in this demonstration was made from a hydrogel material. Like the crumpled graphene, the hydrogel is highly deformable and stretchable, so the three layers remain in contact even while being flexed and pulled.

Though this initial demonstration was specifically to make a supercapacitor, the same crumpling technique could be applied to other uses, Zhao says. For example, the crumpled graphene material might be used as one electrode in a flexible battery, or could be used to make a stretchable sensor for specific chemical or biological molecules.

Here is a link to and a citation for the paper,

Stretchable and High-Performance Supercapacitors with Crumpled Graphene Papers by Jianfeng Zang, Changyong Cao, Yaying Feng, Jie Liu, & Xuanhe Zhao. Scientific Reports 4, Article number: 6492 doi:10.1038/srep06492 Published 01 October 2014

This is an open access article.

ETA Oct. 8, 2014: Dexter Johnson of the Nanoclast blog on the IEEE (Institute of Electrical and Electronics Engineers) website has an Oct. 7, 2014 post where he comments about the ‘flexibility’ aspect of this work.