Category Archives: energy

Taking the baking out of aircraft manufacture

It seems that ovens are an essential piece of equipment when manufacturing aircraft parts but that may change if research from MIT (Massachusetts Institute of Technology) proves successful. An April 14, 2015 news item on ScienceDaily describes the current process and the MIT research,

Composite materials used in aircraft wings and fuselages are typically manufactured in large, industrial-sized ovens: Multiple polymer layers are blasted with temperatures up to 750 degrees Fahrenheit, and solidified to form a solid, resilient material. Using this approach, considerable energy is required first to heat the oven, then the gas around it, and finally the actual composite.

Aerospace engineers at MIT have now developed a carbon nanotube (CNT) film that can heat and solidify a composite without the need for massive ovens. When connected to an electrical power source, and wrapped over a multilayer polymer composite, the heated film stimulates the polymer to solidify.

The group tested the film on a common carbon-fiber material used in aircraft components, and found that the film created a composite as strong as that manufactured in conventional ovens — while using only 1 percent of the energy.

The new “out-of-oven” approach may offer a more direct, energy-saving method for manufacturing virtually any industrial composite, says Brian L. Wardle, an associate professor of aeronautics and astronautics at MIT.

“Typically, if you’re going to cook a fuselage for an Airbus A350 or Boeing 787, you’ve got about a four-story oven that’s tens of millions of dollars in infrastructure that you don’t need,” Wardle says. “Our technique puts the heat where it is needed, in direct contact with the part being assembled. Think of it as a self-heating pizza. … Instead of an oven, you just plug the pizza into the wall and it cooks itself.”

Wardle says the carbon nanotube film is also incredibly lightweight: After it has fused the underlying polymer layers, the film itself — a fraction of a human hair’s diameter — meshes with the composite, adding negligible weight.

An April 14, 2015 MIT news release, which originated the news item, describes the origins of the team’s latest research, the findings, and the implications,

Carbon nanotube deicers

Wardle and his colleagues have experimented with CNT films in recent years, mainly for deicing airplane wings. The team recognized that in addition to their negligible weight, carbon nanotubes heat efficiently when exposed to an electric current.

The group first developed a technique to create a film of aligned carbon nanotubes composed of tiny tubes of crystalline carbon, standing upright like trees in a forest. The researchers used a rod to roll the “forest” flat, creating a dense film of aligned carbon nanotubes.

In experiments, Wardle and his team integrated the film into airplane wings via conventional, oven-based curing methods, showing that when voltage was applied, the film generated heat, preventing ice from forming.

The deicing tests inspired a question: If the CNT film could generate heat, why not use it to make the composite itself?

How hot can you go?

In initial experiments, the researchers investigated the film’s potential to fuse two types of aerospace-grade composite typically used in aircraft wings and fuselages. Normally the material, composed of about 16 layers, is solidified, or cross-linked, in a high-temperature industrial oven.

The researchers manufactured a CNT film about the size of a Post-It note, and placed the film over a square of Cycom 5320-1. They connected electrodes to the film, then applied a current to heat both the film and the underlying polymer in the Cycom composite layers.

The team measured the energy required to solidify, or cross-link, the polymer and carbon fiber layers, finding that the CNT film used one-hundredth the electricity required for traditional oven-based methods to cure the composite. Both methods generated composites with similar properties, such as cross-linking density.

Wardle says the results pushed the group to test the CNT film further: As different composites require different temperatures in order to fuse, the researchers looked to see whether the CNT film could, quite literally, take the heat.

“At some point, heaters fry out,” Wardle says. “They oxidize, or have different ways in which they fail. What we wanted to see was how hot could this material go.”

To do this, the group tested the film’s ability to generate higher and higher temperatures, and found it topped out at over 1,000 F. In comparison, some of the highest-temperature aerospace polymers require temperatures up to 750 F in order to solidify.

“We can process at those temperatures, which means there’s no composite we can’t process,” Wardle says. “This really opens up all polymeric materials to this technology.”

The team is working with industrial partners to find ways to scale up the technology to manufacture composites large enough to make airplane fuselages and wings.

“There needs to be some thought given to electroding, and how you’re going to actually make the electrical contact efficiently over very large areas,” Wardle says. “You’d need much less power than you are currently putting into your oven. I don’t think it’s a challenge, but it has to be done.”

Gregory Odegard, a professor of computational mechanics at Michigan Technological University, says the group’s carbon nanotube film may go toward improving the quality and efficiency of fabrication processes for large composites, such as wings on commercial aircraft. The new technique may also open the door to smaller firms that lack access to large industrial ovens.

“Smaller companies that want to fabricate composite parts may be able to do so without investing in large ovens or outsourcing,” says Odegard, who was not involved in the research. “This could lead to more innovation in the composites sector, and perhaps improvements in the performance and usage of composite materials.”

It can be interesting to find out who funds the research (from the news release),

This research was funded in part by Airbus Group, Boeing, Embraer, Lockheed Martin, Saab AB, TohoTenax, ANSYS Inc., the Air Force Research Laboratory at Wright-Patterson Air Force Base, and the U.S. Army Research Office.

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

Impact of carbon nanotube length on electron transport in aligned carbon nanotube networks by Jeonyoon Lee, Itai Y. Stein, Mackenzie E. Devoe, Diana J. Lewis, Noa Lachman, Seth S. Kessler, Samuel T. Buschhorn, and Brian L. Wardle. Appl. Phys. Lett. 106, 053110 (2015);

This paper is behind a paywall.

Combining the best qualities of batteries and supercapacitors at the University of California at Los Angeles (UCLA)

There’s a reason why I’ve been feeling impatient about batteries and supercapacitors according to an April 2, 2015 news item on Nanowerk,

The dramatic rise of smartphones, tablets, laptops and other personal and portable electronics has brought battery technology to the forefront of electronics research. Even as devices have improved by leaps and bounds, the slow pace of battery development has held back technological progress.

Now, researchers at UCLA’s California NanoSystems Institute have successfully combined two nanomaterials to create a new energy storage medium that combines the best qualities of batteries and supercapacitors.

An April 1, 2015 UCLA news release, which originated the news item, describes the challenge and how the scientists addressed it (Note: A link has been removed),

Supercapacitors are electrochemical components that can charge in seconds rather than hours and can be used for 1 million recharge cycles. Unlike batteries, however, they do not store enough power to run our computers and smartphones.

The new hybrid supercapacitor stores large amounts of energy, recharges quickly and can last for more than 10,000 recharge cycles. The CNSI scientists also created a microsupercapacitor that is small enough to fit in wearable or implantable devices. Just one-fifth the thickness of a sheet of paper, it is capable of holding more than twice as much charge as a typical thin-film lithium battery.

The study, led by Richard Kaner, distinguished professor of chemistry and biochemistry and materials science and engineering, and Maher El-Kady, a postdoctoral scholar, was published in the Proceedings of the National Academy of Sciences.

“The microsupercapacitor is a new evolving configuration, a very small rechargeable power source with a much higher capacity than previous lithium thin-film microbatteries,” El-Kady said.

The new components combine laser-scribed graphene, or LSG — a material that can hold an electrical charge, is very conductive, and charges and recharges very quickly — with manganese dioxide, which is currently used in alkaline batteries because it holds a lot of charge and is cheap and plentiful. They can be fabricated without the need for extreme temperatures or the expensive “dry rooms” required to produce today’s supercapacitors.

“Let’s say you wanted to put a small amount of electrical current into an adhesive bandage for drug release or healing assistance technology,” Kaner said. “The microsupercapacitor is so thin you could put it inside the bandage to supply the current. You could also recharge it quickly and use it for a very long time.”

The researchers found that the supercapacitor could quickly store electrical charge generated by a solar cell during the day, hold the charge until evening and then power an LED overnight, showing promise for off-grid street lighting.

“The LSG–manganese-dioxide capacitors can store as much electrical charge as a lead acid battery, yet can be recharged in seconds, and they store about six times the capacity of state-of-the-art commercially available supercapacitors,” Kaner said. “This scalable approach for fabricating compact, reliable, energy-dense supercapacitors shows a great deal of promise in real-world applications, and we’re very excited about the possibilities for greatly improving personal electronics technology in the near future.”

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

Engineering three-dimensional hybrid supercapacitors and microsupercapacitors for high-performance integrated energy storage by Maher F. El-Kady, Melanie Ihns, Mengping Li, Jee Youn Hwang, Mir F. Mousavi, Lindsay Chaney, Andrew T. Lech, and Richard B. Kaner. Published online before print March 23, 2015, doi: 10.1073/pnas.1420398112 PNAS March 23, 2015

This paper is behind a paywall.

One last bit, Dexter Johnson in an April 3, 2015 post on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website) provides some insight into the research,

The story of graphene in supercapacitors can be represented by the old adage: its greatest strength is its greatest weakness. Of course, the name of the game in supercapacitor energy density is surface area. The greater the surface area, the greater number of ions you can store on the electrodes. While graphene has a theoretical surface area of 2630 square meters per gram, this density is only possible with a single, standalone graphene sheet.

But you can’t actually use a standalone sheet for the electrode of a supercapacitor because it will result in a very low volumetric capacitance. ….

So, while the 2-D characteristic of graphene may limit its usable surface area for supercapacitors, it does offer a way to make supercapacitors with small dimensions, something that would be impossible with activated carbon.

It is this strength that the CNSI researchers are aiming to exploit in their supercapacitor, which is small enough to be used as a wearable or implantable device. …

I recommend reading Dexter’s post in its entirety.

Stress makes quantum dots ‘breathe’

A March 19, 2015 news item on ScienceDaily describes some new research on quantum dots,

Researchers at the Department of Energy’s SLAC National Accelerator Laboratory watched nanoscale semiconductor crystals expand and shrink in response to powerful pulses of laser light. This ultrafast “breathing” provides new insight about how such tiny structures change shape as they start to melt — information that can help guide researchers in tailoring their use for a range of applications.

In the experiment using SLAC’s Linac Coherent Light Source (LCLS) X-ray laser, a DOE Office of Science User Facility, researchers first exposed the nanocrystals to a burst of laser light, followed closely by an ultrabright X-ray pulse that recorded the resulting structural changes in atomic-scale detail at the onset of melting.

“This is the first time we could measure the details of how these ultrasmall materials react when strained to their limits,” said Aaron Lindenberg, an assistant professor at SLAC and Stanford who led the experiment. The results were published March 12 [2015] in Nature Communications.

A March 18, 2015 SLAC news release, which originated the news item, provides a general description of quantum dots,

The crystals studied at SLAC are known as “quantum dots” because they display unique traits at the nanoscale that defy the classical physics governing their properties at larger scales. The crystals can be tuned by changing their size and shape to emit specific colors of light, for example.

So scientists have worked to incorporate them in solar panels to make them more efficient and in computer displays to improve resolution while consuming less battery power. These materials have also been studied for potential use in batteries and fuel cells and for targeted drug delivery.

Scientists have also discovered that these and other nanomaterials, which may contain just tens or hundreds of atoms, can be far more damage-resistant than larger bits of the same materials because they exhibit a more perfect crystal structure at the tiniest scales. This property could prove useful in battery components, for example, as smaller particles may be able to withstand more charging cycles than larger ones before degrading.

The news release then goes on to describe the latest research showing the dots ‘breathe’ (Note: A link has been removed),

In the LCLS experiment, researchers studied spheres and nanowires made of cadmium sulfide and cadmium selenide that were just 3 to 5 nanometers, or billionths of a meter, across. The nanowires were up to 25 nanometers long. By comparison, amino acids – the building blocks of proteins – are about 1 nanometer in length, and individual atoms are measured in tenths of nanometers.

By examining the nanocrystals from many different angles with X-ray pulses, researchers reconstructed how they change shape when hit with an optical laser pulse. They were surprised to see the spheres and nanowires expand in width by about 1 percent and then quickly contract within femtoseconds, or quadrillionths of a second. They also found that the nanowires don’t expand in length, and showed that the way the crystals respond to strain was coupled to how their structure melts.

In an earlier, separate study, another team of researchers had used LCLS to explore the response of larger gold particles on longer timescales.

“In the future, we want to extend these experiments to more complex and technologically relevant nanostructures, and also to enable X-ray exploration of nanoscale devices while they are operating,” Lindenberg said. “Knowing how materials change under strain can be used together with simulations to design new materials with novel properties.”

Participating researchers were from SLAC, Stanford and two of their joint institutes, the Stanford Institute for Materials and Energy Sciences (SIMES) and Stanford PULSE Institute; University of California, Berkeley; University of Duisburg-Essen in Germany; and Argonne National Laboratory. The work was supported by the DOE Office of Science and the German Research Council.

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

Visualization of nanocrystal breathing modes at extreme strains by Erzsi Szilagyi, Joshua S. Wittenberg, Timothy A. Miller, Katie Lutker, Florian Quirin, Henrik Lemke, Diling Zhu, Matthieu Chollet, Joseph Robinson, Haidan Wen, Klaus Sokolowski-Tinten, & Aaron M. Lindenberg. Nature Communications 6, Article number: 6577 doi:10.1038/ncomms7577 Published 12 March 2015

This paper is behind a paywall but there is a free preview available through ReadCube Access.

Speeding up the process for converting carbon dioxide into hydrocarbon fuel

This is a personal thrill; it’s the first time in seven years that I’ve received a press release directly from an institution in Asia.

A March 10, 2015 MANA, the International Center for Materials Nanoarchitectonics at NIMS (National Institute for Materials Science) press release announces and describes hydrocarbon fuel research from Japan and China first published online in Nov. 2014 and later in print in January 2015,

A combination of semiconductor catalysts, optimum catalyst shape, gold-copper co-catalyst alloy nanoparticles and hydrous hydrazine reducing agent enables an increase of hydrocarbon generation from CO2 by a factor of ten.

“Solar-energy-driven conversion of CO2 into hydrocarbon fuels can simultaneously generate chemical fuels to meet energy demand and mitigate rising CO2 levels,” explain Jinhua Ye and her colleagues at the International Center for Materials Nanoarchitectonics in their latest report. Now the research team have identified the conditions and catalysts that will maximise the yield of hydrocarbons from CO2, generating ten times previously reported production rates.

Carbon dioxide can be converted into a hydrocarbon by means of ‘reduction reactions’ -a type of reaction that involves reducing the oxygen content of a molecule, increasing the hydrogen content or increasing the electrons. In photocatalytic reduction of CO2 light activates the catalyst for the reaction.

Ye and his team introduced four approaches that each contributed to an increased reaction rate. First, they combined two known semiconductor photocatalysts strontium titanate (STO) and titania [titanium dioxide] (TiO2) – which led to the separation of the charges generated by light and hence a more effective photocatalyst. Second, the high surface area of the nanotubes was made greater by holes in the tube surfaces, which enhances catalysis by increasing the contact between the gases and catalysts. Third, the tubes were decorated with gold-copper (Au3Cu) nanoparticle co-catalysts to further enhance the catalysis, and fourth, they used hydrous hydrazine (N2H4•H2O) as the source of hydrogen.

Although the high hydrogen content of hydrous hydrazine is widely recognised in the context of hydrogen storage there are no previous reports of its use for reduction reactions. The researchers demonstrated that the reducing properties of hydrous hydrazine were so great that oxidation of the co-catalytic nanoparticles – a problem when water or hydrogen are used – was avoided.

The researchers conclude their report, “This opens a feasible route to enhance the photocatalytic efficiency, which also aids the development of photocatalysts and co-catalysts.”


The researchers on this project are associated with the following institutions:

International Center for Materials Nanoarchitectonics (MANA), and the Environmental Remediation Materials Unit,  National Institute for Materials Science (NIMS) 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan

Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo 060-0814, Japan

TU-NIMS Joint Research Center, School of Material Science and Engineering, Tianjin University 92 Weijin Road, Tianjin,  P.R. China

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

Photocatalytic Reduction of Carbon Dioxide by Hydrous Hydrazine over Au–Cu Alloy Nanoparticles Supported on SrTiO3/TiO2 Coaxial Nanotube Arrays by Dr. Qing Kang, Dr. Tao Wang, Dr. Peng Li, Dr. Lequan Liu, Dr. Kun Chang, Mu Li, and Prof. Jinhua Ye. Angewandte Chemie International Edition Volume 54, Issue 3, pages 841–845, January 12, 2015 DOI: 10.1002/anie.201409183 Article first published online: 24 NOV 2014

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This research is behind a paywall.

Hydro-Québec, lithium-ion batteries, and silicate-based nanoboxes

Hydro-Québec (Canada) is making a bit of a splash these days (this is the third mention within less than a week) on my blog, if nowhere else. The latest development was announced in a Feb. 24, 2015 news item on Nanowerk (Note: A link has been removed),

Researchers from Singapore’s Institute of Bioengineering and Nanotechnology (IBN) of A*STAR and Quebec’s IREQ (Hydro-Québec’s research institute) have synthesized silicate-based nanoboxes that could more than double the energy capacity of lithium-ion batteries as compared to conventional phosphate-based cathodes (“Synthesis of Phase-Pure Li2MnSiO4@C Porous Nanoboxes for High-Capacity Li-Ion Battery Cathodes”). This breakthrough could hold the key to longer-lasting rechargeable batteries for electric vehicles and mobile devices.

A Feb. 24, 2015 Hydro-Québec press release (also on Canadian News Wire), which originated the news item, describe the research and the relationship between the two institutions,

“IBN researchers have successfully achieved simultaneous control of the phase purity and nanostructure of Li2MnSiO4 for the first time,” said Professor Jackie Y. Ying, IBN Executive Director. “This novel synthetic approach would allow us to move closer to attaining the ultrahigh theoretical capacity of silicate-based cathodes for battery applications.”

“We are delighted to collaborate with IBN on this project. IBN’s expertise in synthetic chemistry and nanotechnology allows us to explore new synthetic approaches and nanostructure design to achieve complex materials that pave the way for breakthroughs in battery technology, especially regarding transportation electrification,” said Dr. Karim Zaghib, Director – Energy Storage and Conservation at Hydro-Québec.

Lithium-ion batteries are widely used to power many electronic devices, including smart phones, medical devices and electric vehicles. Their high energy density, excellent durability and lightness make them a popular choice for energy storage. Due to a growing demand for long-lasting, rechargeable lithium-ion batteries for various applications, significant efforts have been devoted to improving the capacity of these batteries. In particular, there is great interest in developing new compounds that may increase energy storage capacity, stability and lifespan compared to conventional lithium phosphate batteries.

The five-year research collaboration between IBN and Hydro-Québec was established in 2011. The researchers plan to further enhance their new cathode materials to create high-capacity lithium-ion batteries for commercialization.

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

Synthesis of phase-pure Li2MnSiO4@C porous nanoboxes for high-capacity Li-ion battery cathodes by Xian-Feng Yang, Jin-Hua Yang, Karim Zaghib, Michel L. Trudeau, and Jackie Y. Ying. Nano Energy Volume 12, March 2015, Pages 305–313 doi:10.1016/j.nanoen.2014.12.021

This paper is behind a paywall.

Here are my two most recent mentions of Hydro-Québec and lithium-ion batteries (both Grafoid and NanoXplore have deals with Hydro-Québec),

Investment in graphene (Grafoid), the Canadian government, and a 2015 federal election (Feb. 23, 2015)

NanoXplore: graphene and graphite in Québec (Canada) (Feb. 20, 2015)

NanoXplore: graphene and graphite in Québec (Canada)

For the second time this week I’m going to be mentioning the province of Québec (Canada) in relation to its ‘nanotechnology’ businesses (see: Cellulose nanocrystals (CNC), also known as nanocrystalline cellulose (NCC), and toxicity; some Celluforce news; anti-petroleum extremists posted on Feb. 19, 2015). A Feb. 20, 2015 news item on Azonano announces a graphene production facility in the Montréal area,

Group NanoXplore Inc., a Montreal-based company specialising in the production and application of graphene and its derivative materials, announced today that its graphene production facility is in full operation with a capacity of 3 metric tonnes per year. This is the largest graphene production capacity in Canada and, outside of China, one of the 5 largest in the world.

A Feb. 19, 2015 NanoXplore news release on MarketWire, which originated the news item, provides a bit more detail in amidst the promotional hype,

NanoXplore’s production process is unique and the core of the company’s competitive advantage. The proprietary process gently and efficiently creates pristine graphene from natural flake graphite without creating the crystalline defects that can limit performance. The process also functionalises the graphene material during production making subsequent mixing with a broad range of industrial materials simple and efficient. NanoXplore’s facility is routinely producing several standard grades of graphene as well as derivative products such as a unique graphite-graphene composite suitable for anodes in Li-ion batteries. [emphasis mine]

Another graphite connection in Québec

Interestingly, back in 2012 Hydro-Québec signed a deal with another Québec-based company, Focus Graphite (which owns a graphite deposit in the northeastern part of the province) to explore ways to produce more efficient lithium-ion batteries (my Nov 27, 2012 posting).

Getting back to the news release, it also provides a summary description of NanoXplore,

NanoXplore is a privately held advanced materials company focused on the large-scale production of high quality graphene and the integration of graphene into real world industrial products. NanoXplore achieves significant improvements in performance for its customers with very low levels of graphene because its material is of high quality (few defects, highly dispersible), because the production process can easily tune the dimensions of the graphene platelets, and because NanoXplore has specific expertise in dispersing graphene in a broad range of industrial materials. NanoXplore partners with its customers to integrate graphene into their products and processes, providing them with innovative products and a strong competitive advantage.

Graphite mines

NanoXplore, too, has some sort of relationship with a graphite mine or, in this case mining company, Mason Graphite (from the NanoXplore website’s Investors’ page),


Partnered with Canadian mining company Mason Graphite, NanoXplore has access to lower quartile graphite/graphene production costs as well as a stable, long term, large flake source of raw material. Local government bodies have embraced the graphite-graphene cluster. With production and R&D centrally located in Montreal, NanoXplore offers world class innovation and true intellectual property safety for its formulation partners.

By the way, Benoit Gascon, NanoXplore’s board chair (scroll down to the bottom  of the team list) is also Mason Graphite’s Chief Executive Officer (CEO). The company has recently announced a detailed study on large-scale production of value-added graphite products (from a Feb. 11, 2015 Mason Graphite news release),

Mason Graphite Inc. (“Mason Graphite” or the “Company”) (TSX VENTURE:LLG)(OTCQX:MGPHF) announces that it has initiated a detailed study for large scale processing of value-added graphite products.

Value-added processing includes micronization, additional purification, spheronization and coating, resulting in graphite products that are suitable for a wide range of electrochemical applications (including alkaline batteries, lithium-ion batteries and fuel cells), technical applications (including carbon brushes, brake linings, plastics and lubricants), and other specialized uses.

The development and validation of the fabrication processes for these graphite products will be carried out by the National Research Council of Canada (“NRC”) along with Hatch, and is expected to conclude by the end of 2015. Following initial scoping work, equipment trials and product testing, the Company intends to provide preliminary results and an updated work program by mid-2015.

The NRC is the Government of Canada’s premier research and technology organization. Hatch is an engineering firm located in Montreal which is already working closely with Mason Graphite on the development of the Lac Gueret Graphite Project.

Other parts of Canada and the graphite/graphene enterprise

NanoXplore and Focus Graphite are not the only companies with connections to a graphite mine in Québec. There’s also Vancouver (Canada)-based Lomiko Metals (mentioned here in an April 17, 2013 posting [for the first time]. A. Paul Gill, Lomiko’s CEO, seems to be pursuing a similar business strategy in that Lomiko, too, has a number of business alliances, e.g., the mine, a research and development laboratory, etc. Moving out of Québec, there is also a graphite mine in Ontario owned by Northern Graphite (my Feb. 6, 2012 posting). It seems Canadians in eastern Canada have a valuable resource in graphite flakes.

Cellulose nanocrystals (CNC), also known as nanocrystalline cellulose (NCC), and toxicity; some Celluforce news; anti-petroleum extremists

The February 2015 issue of Industrial Biotechnology is hosting a special in depth research section on the topic of cellulose nanotechnology. A Feb. 19, 2015 news item on features a specific article in the special section (Note: A link has been removed),

Novel nanomaterials derived from cellulose have many promising industrial applications, are biobased and biodegradable, and can be produced at relatively low cost. Their potential toxicity—whether ingested, inhaled, on contact with the skin, or on exposure to cells within the body—is a topic of intense discussion, and the latest evidence and insights on cellulose nanocrystal toxicity are presented in a Review article in Industrial Biotechnology.

Maren Roman, PhD, Virginia Tech, Blacksburg, VA, describes the preparation of cellulose nanocrystals (CNCs) and highlights the key factors that are an essential part of studies to assess the potential adverse health effects of CNCs by various types of exposure. In the article “Toxicity of Cellulose Nanocrystals: A Review” , Dr. Roman discusses the current literature on the pulmonary, oral, dermal, and cytotoxicity of CNCs, provides an in-depth view on their effects on human health, and suggests areas for future research.

There has been much Canadian investment both federal and provincial in cellulose nanocrystals (CNC). There’s also been a fair degree of confusion regarding the name. In Canada, which was a research leader initially, it was called nanocrystalline cellulose (NCC) but over time a new term was coined cellulose nanocrystals (CNC). The new name was more in keeping with the naming conventions for other nanoscale cellulose materials such as  cellulose nanofibrils, etc. Hopefully, this confusion will resolve itself now that Celluforce, a Canadian company, has trademarked NCC. (More about Celluforce later in this post.)

Getting back to toxicity and CNC, here’s a link to and a citation for Maron’s research paper,

Toxicity of Cellulose Nanocrystals: A Review by Roman Maren. Industrial Biotechnology. February 2015, 11(1): 25-33. doi:10.1089/ind.2014.0024.

The article is open access at this time. For anyone who doesn’t have the time to read it, here’s the conclusion,

Current studies of the oral and dermal toxicity of CNCs have shown a lack of adverse health effects. The available studies, however, are still very limited in number (two oral toxicity studies and three dermal toxicity studies) and in the variety of tested CNC materials (CelluForce’s NCC). Additional oral and dermal toxicity studies are needed to support the general conclusion that CNCs are nontoxic upon ingestion or contact with the skin. Studies of pulmonary and cytotoxicity, on the other hand, have yielded discordant results. The questions of whether CNCs have adverse health effects on inhalation and whether they elicit inflammatory or oxidative stress responses at the cellular level therefore warrant further investigation. The toxicity of CNCs will depend strongly on their physicochemical properties—in particular, surface chemistry, including particle charge, and degree of aggregation, which determines particle shape and dimensions. Therefore, these properties—which in turn depend strongly on the cellulose source, CNC preparation procedure, and post-processing or sample preparation methods, such as lyophilization, aerosolization, sonication, or sterilization—need to be carefully measured in the final samples.

Another factor that might affect the outcomes of toxicity studies are sample contaminants, such as endotoxins or toxic chemical impurities. Samples for exposure tests should therefore be carefully analyzed for such contaminants prior to testing. Ideally, because detection of toxic chemical contaminants may be difficult, control experiments should be carried out with suitable blanks from which the CNCs have been removed, for example by membrane filtration. Moreover, especially in cytotoxicity assessments, the effect of CNCs on pH and their aggregation in the cell culture medium need to be monitored. Only by careful particle characterization and exclusion of interfering factors will we be able to develop a detailed understanding of the potential adverse health effects of CNCs.

If I understand this rightly, CNC seems safe (more or less) when ingested orally (food/drink) or applied to the skin (dermal application) but inhalation seems problematic and there are indications that this could lead to inflammation of lung cells. Other conclusions suggest both the source for the cellulose and CNC preparation may affect its toxicity. I encourage you to read the whole research paper as this author provides good explanations of the terms and summaries of previous research, as well as, some very well considered research.

Here’s more about Industrial Biotechnology’s special research section in the February 2015 issue, from a Feb. 19, 2015 Mary Ann Liebert publishers press release (also on EurekAlert*),

The article is part of an IB IN DEPTH special research section entitled “Cellulose Nanotechnology: Fundamentals and Applications,” led by Guest Editors Jose Moran-Mirabal, PhD and Emily Cranston, PhD, McMaster University, Hamilton, Canada. In addition to the Review article by Dr. Roman, the issue includes Reviews by M. Rose, M. Babi, and J. Moran-Mirabal (“The Study of Cellulose Structure and Depolymerization Through Single-Molecule Methods”) and by X.F. Zhao and W.T. Winter (“Cellulose/cellulose-based nanospheres: Perspectives and prospective”); Original Research articles by A. Rivkin, T. Abitbol, Y. Nevo, et al. (“Bionanocomposite films from resilin-CBD bound to cellulose nanocrystals), and P. Criado, C. Fraschini, S. Salmieri, et al. (“Evaluation of antioxidant cellulose nanocrystals and applications in gellan gum films”); and the Overview article “Cellulose Nanotechnology on the Rise,” by Drs. Moran-Mirabal and Cranston.

Meanwhile Celluforce announces a $4M ‘contribution’ from Sustainable Development Technology Canada (SDTC), from a Feb. 16, 2015 Celluforce news release,

CelluForce welcomes the announcement by Sustainable Development Technology Canada (SDTC) of a contribution of $4.0 million to optimize the extraction process of Nanocrystaline Cellulose (NCC) from dry wood pulp and develop applications for its use in the oil and gas sector. The announcement was made in Quebec City today [Feb. 16, 2015] by the Honourable Greg Rickford, Minister of Natural Resources and Minister for the Federal Economic Development Initiative for Northern Ontario.

NCC is a fundamental building block of trees that can be extracted from the forest biomass and has unique properties that offer a wide range of potential applications. Measured in units as small as nanometres, these tiny structures have strength properties comparable to steel and will have uses in a variety of industrial sectors. In particular, NCC is touted as having the potential to significantly advance the oil and gas industry.

Our Government is positioning Canada as a global leader in the clean technology sector by supporting innovative projects aimed at growing our economy while contributing to a cleaner environment,” said the Honourable Greg Rickford, Canada’s Minister of Natural Resources. [emphasis mine] “By developing our resources responsibly, exploring next-generation transportation and advancing clean energy technology, the projects announced today will create jobs and improve innovation opportunities in Quebec and across Canada.”

“World-class research led to the development of this ground breaking extraction process and placed Canada at the leading edge of NCC research”, stated René Goguen, Acting President of CelluForce Inc. “This announcement by SDTC sets the stage for the pre-commercial development of applications that will not only support Canada’s forest sector but also the oil and gas sector, both of which are important drivers of the Canadian economy.”

This project will further improve and optimize the process developed by CelluForce to extract nanocrystalline cellulose (CelluForce NCC™) from dry wood pulp. In addition to improving the extraction process, this project will investigate additional applications for the oil-and-gas industry such as cementing using this renewable forestry resource.

There’s very little information in this news release other than the fact that CelluForce’s $4M doesn’t need to be repaid seeing it’s described as a ‘contribution’ rather than an investment. The difference between a contribution and a grant, which is what these funds used to be called, somewhat mystifies me unless this is a translation issue.

As for the news release content, it is remarkably scant. This $4M will be spent on improving the extraction process and on applications for the oil and gas industry. Neither the improvements nor the possible applications are described. Hopefully, the government has some means of establishing whether or not those funds (sorry, the contribution) were used for the purposes described.

I am glad to see this in this news release, “Our Government is positioning Canada as a global leader in the clean technology sector …” although I’m not sure how it fits with recent attempts to brand environmentalists as part of an ‘anti-petroleum’ movement as described in a Feb. 19, 2015 post by Glyn Moody for Techdirt (Note: A link has been removed),

As Techdirt has been warning for some time, one of the dangers with the flood of “anti-terrorist” laws and powers is that they are easily redirected against other groups for very different purposes. A story in the Globe and Mail provides another chilling reminder of how that works:

The RCMP [Royal Canadian Mounted Police] has labelled the “anti-petroleum” movement as a growing and violent threat to Canada’s security, raising fears among environmentalists that they face increased surveillance, and possibly worse, under the Harper government’s new terrorism legislation.

As the Globe and Mail article makes clear, environmentalists are now being considered as part of an “anti-petroleum” movement. That’s not just some irrelevant rebranding: it means that new legislation supposedly targeting “terrorism” can be applied.

It seems logically incoherent to me that the government wants clean tech while condemning environmentalists. Whether or not you buy climate change science (for the record, I do), you have to admit that we are running out of petroleum. At heart, both the government and the environmentalists have to agree that we need new sources for fuel. It doesn’t make any sense to spend valuable money, time, and resources on pursuing environmentalists.

This business about the ‘anti-petroleum’ movement reminds me of a copyright kerfuffle including James Moore, currently the Minister of Industry, and writer Cory Doctorow. Moore, Minister of Canadian Heritage at the time, at some sort of public event, labeled Doctorow as a ‘radical extremist’ regarding his (Doctorow’s) views on copyright. The comments achieved notoriety when it appeared that Moore and the organizers denied the comments ever took place. The organizers seemed to have edited the offending video and Moore made public denials. You can read more about the incident in my June 25, 2010 post. Here’s an excerpt from the post which may explain why I feel there is a similarity,

… By simultaneously linking individuals who use violence to achieve their ends (the usual application for the term ‘radical extremists’) to individuals who are debating, discussing, and writing commentaries critical of your political aims you render the term into a joke and you minimize the violence associated with it.

Although with ‘anti-petroleum’, it seems they could decide any dissension is a form of violence. It should be noted that in Canada the Ministry of Industry, is tightly coupled with the Ministry of Natural Resources since the Canadian economy has been and continues to be largely resource-based.

For anyone interested in CelluForce and NCC/CNC, here’s a sampling of my previous posts on the topic,

CelluForce (nanocrystalline cellulose) plant opens (Dec. 15, 2011)

Double honours for NCC (ArboraNano and CelluForce recognized) (May 25, 2012)

You say nanocrystalline cellulose, I say cellulose nanocrystals; CelluForce at Japan conference and at UK conference (Oct. 15, 2012)

Designing nanocellulose (?) products in Finland; update on Canada’s CelluForce (Oct. 3, 2013) Note: CelluForce stopped producing NCC due to a growing stockpile.

There’s a lot more about CNC on this blog* should you care to search. One final note, I gather there’s a new interim boss at CelluForce, René Goguen replacing Jean Moreau.

* EurekAlert link added Feb. 20, 2015.

* ‘on the CNC blog’ changed to ‘about CNC on this blog’ on March 4, 2015.

Kevlar-wrapped batteries on an airplane

Researchers at the University of Michigan are not trying to bulletproof lithium-ion batteries with kevlar. Rather, they’re trying prevent fires. From a Jan. 27, 2015 University of Michigan news release (also on EurekAlert),

New battery technology from the University of Michigan should be able to prevent the kind of fires that grounded Boeing 787 Dreamliners in 2013.

The innovation is an advanced barrier between the electrodes in a lithium-ion battery.

Made with nanofibers extracted from Kevlar, the tough material in bulletproof vests, the barrier stifles the growth of metal tendrils that can become unwanted pathways for electrical current.

A U-M team of researchers also founded Ann Arbor-based Elegus Technologies to bring this research from the lab to market. Mass production is expected to begin in the fourth quarter 2016.

“Unlike other ultra strong materials such as carbon nanotubes, Kevlar is an insulator,” said Nicholas Kotov, the Joseph B. and Florence V. Cejka Professor of Engineering. “This property is perfect for separators that need to prevent shorting between two electrodes.”

Lithium-ion batteries work by shuttling lithium ions from one electrode to the other. This creates a charge imbalance, and since electrons can’t go through the membrane between the electrodes, they go through a circuit instead and do something useful on the way.

But if the holes in the membrane are too big, the lithium atoms can build themselves into fern-like structures, called dendrites, which eventually poke through the membrane. If they reach the other electrode, the electrons have a path within the battery, shorting out the circuit. This is how the battery fires on the Boeing 787 are thought to have started.

“The fern shape is particularly difficult to stop because of its nanoscale tip,” said Siu On Tung, a graduate student in Kotov’s lab, as well as chief technology officer at Elegus. “It was very important that the fibers formed smaller pores than the tip size.”

While the widths of pores in other membranes are a few hundred nanometers, or a few hundred-thousandths of a centimeter, the pores in the membrane developed at U-M are 15-to-20 nanometers across. They are large enough to let individual lithium ions pass, but small enough to block the 20-to-50-nanometer tips of the fern-structures.

The researchers made the membrane by layering the fibers on top of each other in thin sheets. This method keeps the chain-like molecules in the plastic stretched out, which is important for good lithium-ion conductivity between the electrodes, Tung said.

“The special feature of this material is we can make it very thin, so we can get more energy into the same battery cell size, or we can shrink the cell size,” said Dan VanderLey, an engineer who helped found Elegus through U-M’s Master of Entrepreneurship program. “We’ve seen a lot of interest from people looking to make thinner products.”

Thirty companies have requested samples of the material.

Kevlar’s heat resistance could also lead to safer batteries as the membrane stands a better chance of surviving a fire than most membranes currently in use.

While the team is satisfied with the membrane’s ability to block the lithium dendrites, they are currently looking for ways to improve the flow of loose lithium ions so that batteries can charge and release their energy more quickly.

For anyone unfamiliar with the Boeing 787 Dreamliner fires, caused by lithium-ion batteries, these Boeing fires and others are mentioned in my May 29, 2013 post (Life-cycle assessment for electric vehicle lithium-ion batteries and nanotechnology is a risk analysis) scroll down about 50% of the way.

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

A dendrite-suppressing composite ion conductor from aramid nanofibres by Siu-On Tung, Szushen Ho, Ming Yang, Ruilin Zhang, & Nicholas A. Kotov. Nature Communications 6, Article number: 6152 doi:10.1038/ncomms7152 Published 27 January 2015

This paper is behind a paywall.

You can find out more about Elegus Technologies here.

A use for fullerenes—inside insulation plastic for high-voltage cables

A Jan. 27, 2015 news item on Nanowerk, describes research which suggests that there may a new use for buckminsterfullerenes (or what they’re calling ‘carbon nanoballs’),

Researchers at Chalmers University of Technology [Sweden] have discovered that the insulation plastic used in high-voltage cables can withstand a 26 per cent higher voltage if nanometer-sized carbon balls are added. This could result in enormous efficiency gains in the power grids of the future, which are needed to achieve a sustainable energy system.

The renewable energy sources of tomorrow will often be found far away from the end user. Wind turbines, for example, are most effective when placed out at sea. Solar energy will have the greatest impact on the European energy system if focus is on transport of solar power from North Africa and Southern Europe to Northern Europe.

“Reducing energy losses during electric power transmission is one of the most important factors for the energy systems of the future,” says Chalmers researcher Christian Müller. “The other two are development of renewable energy sources and technologies for energy storage.”

The Jan. 27, 2015 Chalmers University of Technology press release (also on EurekAlert) by Johanna Wilde, which originated the news item, provides more information about the research,

Together with colleagues from Chalmers and the company Borealis in Stenungsund, he [Müller] has found a powerful method for reducing energy losses in alternating current cables.  The results were recently published in Advanced Materials, a highly ranked scientific journal.

The researchers have shown that different variants of the C60 carbon ball, a nanomaterial in the fullerene molecular group, provide strong protection against breakdown of the insulation plastic used in high-voltage cables. Today the voltage in the cables has to be limited to prevent the insulation layer from getting damaged. The higher the voltage the more electrons can leak out into the insulation material, a process which leads to breakdown.

It is sufficient to add very small amounts of fullerene to the insulation plastic for it to withstand a voltage that is 26 per cent higher, without the material breaking down, than the voltage that plastic without the additive can withstand.

“Being able to increase the voltage to this extent would result in enormous efficiency gains in power transmission all over the world,” says Christian Müller. “A major issue in the industry is how transmission efficiency can be improved without making the power cables thicker, since they are already very heavy and difficult to handle.”

Using additives to protect the insulation plastic has been a known concept since the 1970s, but until now it has been unknown exactly what and how much to add. Consequently, additives are currently not used at all for the purpose, and the insulation material is manufactured with the highest possible degree of chemical purity.

In recent years, other researchers have experimented with fullerenes in the electrically conductive parts of high-voltage cables. Until now, though, it has been unknown that the substance can be beneficial for the insulation material.

The Chalmers researchers have now demonstrated that fullerenes are the best voltage stabilizers identified for insulation plastic thus far. This means they have a hitherto unsurpassed ability to capture electrons and thus protect other molecules from being destroyed by the electrons.

To arrive at these findings, the researchers tested a number of molecules that are also used within organic solar cell research at Chalmers. The molecules were tested using several different methods, and were added to pieces of insulation plastic used for high-voltage cables. The pieces of plastic were then subjected to an increasing electric field until they crackled. Fullerenes turned out to be the type of additive that most effectively protects the insulation plastic.

The press release includes some facts about buckyballs or buckminsterfullerenes or fullerenes or C60 or carbon nanoballs, depending on what you want to call them,

 Facts: Carbon ball C60

  • The C60 carbon ball is also called buckminsterfullerene. It consists of 60 carbon atoms that are placed so that the molecule resembles a nanometer-sized football. C60 is included in the fullerene molecular class.
  • Fullerenes were discovered in 1985, which resulted in the Nobel Prize in Chemistry in 1996. They have unique electronic qualities and have been regarded as very promising material for several applications. Thus far, however, there have been few industrial usage areas.
  • Fullerenes are one of the five forms of pure carbon that exist. The other four are graphite, graphene/carbon nanotubes, diamond and amorphous carbon, for example soot.

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

A New Application Area for Fullerenes: Voltage Stabilizers for Power Cable Insulation by Markus Jarvid, Anette Johansson, Renee Kroon, Jonas M. Bjuggren, Harald Wutzel, Villgot Englund, Stanislaw Gubanski, Mats R. Andersson, and Christian Müller. Advanced Materials DOI: 10.1002/adma.201404306 Article first published online: 12 DEC 2014

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Here’s an image of wind turbines, an example of equipment which could benefit greatly from better insulation.,

Images: Lina Bertling, Jan-Olof Yxell, Carolina Eek Jaworski, Anette Johansson, Markus Jarvid, Christian Müller

Images: Lina Bertling, Jan-Olof Yxell, Carolina Eek Jaworski, Anette Johansson, Markus Jarvid, Christian Müller

You can find this image and others by clicking on the Chalmers University press release link (assuming the page hasn’t been moved). You can find more information about Borealis (the company Müller is working with) here.

The perfect keyboard: it self-cleans and self-powers and it can identify its owner(s)

There’s a pretty nifty piece of technology being described in a Jan. 21, 2015 news item on Nanowerk, which focuses on the security aspects first (Note: A link has been removed),

In a novel twist in cybersecurity, scientists have developed a self-cleaning, self-powered smart keyboard that can identify computer users by the way they type. The device, reported in the journal ACS Nano (“Personalized Keystroke Dynamics for Self-Powered Human–Machine Interfacing”), could help prevent unauthorized users from gaining direct access to computers.

A Jan. 21, 2015 American Chemical Society (ACS) news release (also on EurekAlert), which originated the news item, continues with the keyboard’s security features before briefly mentioning the keyboard’s self-powering and self-cleaning capabilities,

Zhong Lin Wang and colleagues note that password protection is one of the most common ways we control who can log onto our computers — and see the private information we entrust to them. But as many recent high-profile stories about hacking and fraud have demonstrated, passwords are themselves vulnerable to theft. So Wang’s team set out to find a more secure but still cost-effective and user-friendly approach to safeguarding what’s on our computers.

The researchers developed a smart keyboard that can sense typing patterns — including the pressure applied to keys and speed — that can accurately distinguish one individual user from another. So even if someone knows your password, he or she cannot access your computer because that person types in a different way than you would. It also can harness the energy generated from typing to either power itself or another small device. And the special surface coating repels dirt and grime. The scientists conclude that the keyboard could provide an additional layer of protection to boost the security of our computer systems.

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

Personalized Keystroke Dynamics for Self-Powered Human–Machine Interfacing by Jun Chen, Guang Zhu, Jin Yang, Qingshen Jing, Peng Bai, Weiqing Yang, Xuewei Qi, Yuanjie Su, and Zhong Lin Wang. ACS Nano, Article ASAP DOI: 10.1021/nn506832w Publication Date (Web): December 30, 2014

Copyright © 2014 American Chemical Society

This paper is behind a paywall. I did manage a peek at the paper and found that the keyboard is able to somehow harvest the mechanical energy of typing and turn it into electricity so it can self-power. Self-cleaning is made possible by a nanostructure surface modification. An idle thought and a final comment. First, I wonder what happens if you want to or have to share your keyboard? Second, a Jan. 21, 2015 article about the intelligent keyboard by Luke Dormehl for Fast Company notes that the researchers are from the US and China and names two of the institutions involved in this collaboration, Georgia Institute of Technology and the Beijing Institute of Nanoenergy and Nanosystems,.

ETA Jan. 23, 2015: There’s a Georgia Institute of Technology Jan. 21, 2015 news release on EurekAlert about the intelligent keyboard which offers more technical details such as these,

Conventional keyboards record when a keystroke makes a mechanical contact, indicating the press of a specific key. The intelligent keyboard records each letter touched, but also captures information about the amount of force applied to the key and the length of time between one keystroke and the next. Such typing style is unique to individuals, and so could provide a new biometric for securing computers from unauthorized use.

In addition to providing a small electrical current for registering the key presses, the new keyboard could also generate enough electricity to charge a small portable electronic device or power a transmitter to make the keyboard wireless.

An effect known as contact electrification generates current when the user’s fingertips touch a plastic material on which a layer of electrode material has been coated. Voltage is generated through the triboelectric and electrostatic induction effects. Using the triboelectric effect, a small charge can be produced whenever materials are brought into contact and then moved apart.

“Our skin is dielectric and we have electrostatic charges in our fingers,” Wang noted. “Anything we touch can become charged.”

Instead of individual mechanical keys as in traditional keyboards, Wang’s intelligent keyboard is made up of vertically-stacked transparent film materials. Researchers begin with a layer of polyethylene terephthalate between two layers of indium tin oxide (ITO) that form top and bottom electrodes.

Next, a layer of fluorinated ethylene propylene (FEP) is applied onto the ITO surface to serve as an electrification layer that generates triboelectric charges when touched by fingertips. FEP nanowire arrays are formed on the exposed FEP surface through reactive ion etching.

The keyboard’s operation is based on coupling between contact electrification and electrostatic induction, rather than the traditional mechanical switching. When a finger contacts the FEP, charge is transferred at the contact interface, injecting electrons from the skin into the material and creating a positive charge.

When the finger moves away, the negative charges on the FEP side induces positive charges on the top electrode, and equal amounts of negative charges on the bottom electrode. Consecutive keystrokes produce a periodic electrical field that drives reciprocating flows of electrons between the electrodes. Though eventually dissipating, the charges remain on the FEP surface for an extended period of time.

Wang believes the new smart keyboard will be competitive with existing keyboards, in both cost and durability. The new device is based on inexpensive materials that are widely used in the electronics industry.