Tag Archives: graphene

Graphene-boron nitride material research from Rice University (US) and Polytechnique Montréal (Canada)

A Jan. 13, 2016 Rice University news release (also on EurekAlert) highlights computational research on hybrid material (graphene-boron nitride),

Developing novel materials from the atoms up goes faster when some of the trial and error is eliminated. A new Rice University and Montreal Polytechnic study aims to do that for graphene and boron nitride hybrids.

Rice materials scientist Rouzbeh Shahsavari and Farzaneh Shayeganfar, a postdoctoral researcher at Montreal Polytechnic (also known as École Polytechnique de Montréal or Polytechnique de Montréal), designed computer simulations that combine graphene, the atom-thick form of carbon, with either carbon or boron nitride nanotubes.

Their hope is that such hybrids can leverage the best aspects of their constituent materials. Defining the properties of various combinations would simplify development for manufacturers who want to use these exotic materials in next-generation electronics. The researchers found not only electronic but also magnetic properties that could be useful.

Shahsavari’s lab studies materials to see how they can be made more efficient, functional and environmentally friendly. They include macroscale materials like cement and ceramics as well as nanoscale hybrids with unique properties.

“Whether it’s on the macro- or microscale, if we can know specifically what a hybrid will do before anyone goes to the trouble of fabricating it, we can save cost and time and perhaps enable new properties not possible with any of the constituents,” Shahsavari said.

His lab’s computer models simulate how the intrinsic energies of atoms influence each other as they bond into molecules. For the new work, the researchers modeled hybrid structures of graphene and carbon nanotubes and of graphene and boron nitride nanotubes.

“We wanted to investigate and compare the electronic and potentially magnetic properties of different junction configurations, including their stability, electronic band gaps and charge transfer,” he said. “Then we designed three different nanostructures with different junction geometry.”

Two were hybrids with graphene layers seamlessly joined to carbon nanotubes. The other was similar but, for the first time, they modeled a hybrid with boron nitride nanotubes. How the sheets and tubes merged determined the hybrid’s properties. They also built versions with nanotubes sandwiched between graphene layers.

Graphene is a perfect conductor when its atoms align as hexagonal rings, but the material becomes strained when it deforms to accommodate nanotubes in hybrids. The atoms balance their energies at these junctions by forming five-, seven- or eight-member rings. These all induce changes in the way electricity flows across the junctions, turning the hybrid material into a valuable semiconductor.

The researchers’ calculations allowed them to map out a number of effects. For example, it turned out the junctions of the hybrid system create pseudomagnetic fields.

“The pseudomagnetic field due to strain was reported earlier for graphene, but not these hybrid boron nitride and carbon nanostructures where strain is inherent to the system,” Shahsavari said. He noted the effect may be useful in spintronic and nano-transistor applications.

“The pseudomagnetic field causes charge carriers in the hybrid to circulate as if under the influence of an applied external magnetic field,” he said. “Thus, in view of the exceptional flexibility, strength and thermal conductivity of hybrid carbon and boron nitride systems, we propose the pseudomagnetic field may be a viable way to control the electronic structure of new materials.”

All the effects serve as a road map for nanoengineering applications, Shahsavari said.

“We’re laying the foundations for a range of tunable hybrid architectures, especially for boron nitride, which is as promising as graphene but much less explored,” he said. “Scientists have been studying all-carbon structures for years, but the development of boron nitride and other two-dimensional materials and their various combinations with each other gives us a rich set of possibilities for the design of materials with never-seen-before properties.”

Shahsavari is an assistant professor of civil and environmental engineering and of materials science and nanoengineering.

###

Rice supported the research, and computational resources were provided by Calcul Quebec and Compute Canada.

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

Electronic and pseudomagnetic properties of hybrid carbon/boron-nitride nanomaterials via ab-initio calculations and elasticity theory by Farzaneh Shayeganfar and Rouzbeh Shahsavari. Carbon Volume 99, April 2016, Pages 523–532 doi:10.1016/j.carbon.2015.12.050

This paper is behind a paywall.

Here’s an image illustrating the hybrid material,

Caption: The calculated properties of a three-dimensional hybrid of graphene and boron nitride nanotubes would have pseudomagnetic properties, according to researchers at Rice University and Montreal Polytechnic. Credit: Shahsavari Lab/Rice University

Caption: The calculated properties of a three-dimensional hybrid of graphene and boron nitride nanotubes would have pseudomagnetic properties, according to researchers at Rice University and Montreal Polytechnic. Credit: Shahsavari Lab/Rice University

You gotta shake, shake, shake those nanomaterials out of the water

A team at Michigan Technological University (Michigan Tech) has developed a simple technique for clearing nanoparticles from water according to a Dec. 10, 2015 news item on Nanotechnology Now,

Nano implies small—and that’s great for use in medical devices, beauty products and smartphones—but it’s also a problem. The tiny nanoparticles, nanowires, nanotubes and other nanomaterials that make up our technology eventually find their way into water. The Environmental Protection Agency says more 1,300 commercial products use some kind of nanomaterial. And we just don’t know the full impact on health and the environment.

A Dec. 10, 2015 Michigan Tech news release, which originated the news item, describes the concept and the research in more detail,

“Look at plastic,” says Yoke Khin Yap, a professor of physics at Michigan Technological University. “These materials changed the world over the past decades—but can we clean up all the plastic in the ocean? We struggle to clean up meter-scale plastics, so what happens when we need to clean on the nano-scale?”

The method sounds like a salad dressing recipe: take water, sprinkle in nanomaterials, add oil and shake.

Water and oil don’t mix, of course, but shaking them together is what makes salad dressing so great. Only instead of emulsifying and capturing bits of shitake or basil in tiny olive oil bubbles, this mixture grabs nanomaterials.

Dongyan Zhang, a research professor of physics at Michigan Tech, led the experiments, which covered tests on carbon nanotubes, graphene, boron nitride nanotubes, boron nitride nanosheets and zinc oxide nanowires. Those are used in everything from carbon fiber golf clubs to sunscreen.

“These materials are very, very tiny, and that means if you try to remove them and clean them out of contaminated water, that it’s quite difficult,” Zhang says, adding that techniques like filter paper or meshes often don’t work.

What makes shaking work is the shape of one- and two-dimensional nanomaterials. As the oil and water separate after some rigorous shaking, the wires, tubes and sheets settle at the bottom of the oil, just above the water. The oils trap them. However, zero-dimensional nanomaterials, such as nanospheres do not get trapped.

The researchers, according to the news release, are attempting to anticipate the potential contamination of our water supply by nanomaterials and provide a solution before it happens,

We don’t have to wait until the final vote is in on whether nanomaterials have a positive or negative impact on people’s health and environmental health. With the simplicity of this technique, and how prolific nanomaterials are becoming, removing nanomaterials makes sense. Also, finding ways to effectively remove nanomaterials sooner rather than later could improve the technology’s market potential.

“Ideally for a new technology to be successfully implemented, it needs to be shown that the technology does not cause adverse effects to the environment,” Yap, Zhang and their co-authors write. “Therefore, unless the potential risks of introducing nanomaterials into the environment are properly addressed, it will hinder the industrialization of products incorporating nanotechnology.”

Purifying water and greening nanotechnology could be as simple as shaking a vial of water and oil.

Here’s a video about the research supplied by Michigan Tech,

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

A Simple and Universal Technique To Extract One- and Two-Dimensional Nanomaterials from Contaminated Water by Bishnu Tiwari, Dongyan Zhang, Dustin Winslow, Chee Huei Lee, Boyi Hao, and Yoke Khin Yap. ACS Appl. Mater. Interfaces, 2015, 7 (47), pp 26108–26116 DOI: 10.1021/acsami.5b07542 Publication Date (Web): November 9, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

Graphene and water (G20 Water commentary)

Tim Harper’s, Chief Executive Officer (CEO) of G2O Water, July 13, 2015 commentary was published on Nanotechnology Now. Harper, a longtime figure in the nanotechnology community (formerly CEO of Cientifica, an emerging technologies consultancy and current member of the World Economic Forum, not unexpectedly focused on water,

In the 2015 World Economic Forum’s Global Risks Report survey participants ranked Water Crises as the biggest of all risks, higher than Weapons of Mass Destruction, Interstate Conflict and the Spread of Infectious Diseases (pandemics). Our dependence on the availability of fresh water is well documented, and the United Nations World Water Development Report 2015 highlights a 40% global shortfall between forecast water demand and available supply within the next fifteen years. Agriculture accounts for much of the demand, up to 90% in most of the world’s least-developed countries, and there is a clear relationship between water availability, health, food production and the potential for civil unrest or interstate conflict.

The looming crisis is not limited to water for drinking or agriculture. Heavy metals from urban pollution are finding their way into the aquatic ecosystem, as are drug residues and nitrates from fertilizer use that can result in massive algal blooms. To date, there has been little to stop this accretion of pollutants and in closed systems such as lakes these pollutants are being concentrated with unknown long term effects.

Ten years ago, following discussions with former Israeli Prime Minister Shimon Peres, I organised a conference in Amsterdam called Nanowater to look at how nanotechnology could address global water issues. [emphasis mine] While the meeting raised many interesting points, and many companies proposed potential solutions, there was little subsequent progress.

Rather than a simple mix of one or two contaminants, most real world water can contain hundreds of different materials, and pollutants like heavy metals may be in the form of metal ions that can be removed, but are equally likely to be bound to other larger pieces of organic matter which cannot be simply filtered through nanopores. In fact the biggest obstacle to using nanotechnology in water treatment is the simple fact that small holes are easily blocked, and susceptibility to fouling means that most nanopore membranes quickly become barriers instead of filters.

Fortunately some recent developments in the ‘wonder material’ graphene may change the economics of water. One of the major challenges in the commercialisation of graphene is the ability to create large areas of defect-free material that would be suitable for displays or electronics, and this is a major research topic in Europe where the European Commission is funding graphene research to the tune of a billion euros. …

Tim goes on to describe some graphene-based solutions including a technology developed at the University of South Carolina, which is also mentioned in a July 16, 2015 G20 Water press release,

Fouling of nano/ultrafiltration membranes in oil/water separation is a longstanding issue and a major economic barrier for their widespread adoption. Currently membranes typically show severe fouling, resulting from the strong adhesion of oil on the membrane surface and/or oil penetration inside the membranes. This greatly degrades their performance and shortens service lifetime as well as increasing the energy usage.

G2O™s bio inspired approach uses graphene oxide (GO) for the fabrication of fully-recoverable membranes for high flux, antifouling oil/water separation via functional and structural mimicking of fish scales. The ultra-thin, amphiphilic, water-locking GO coating mimics the thin mucus layer covering fish scales, while the combination of corrugated GO flakes and intrinsic roughness of the porous supports successfully reproduces the hierarchical roughness of fish scales. Cyclic membrane performance evaluation tests revealed circa 100% membrane recovery by facile surface water flushing, establishing their excellent easy-to-recover capability.

The pore sizes can be tuned to specific applications such as water desalination, oil/water separation, storm water treatment and industrial waste water recovery. By varying the GO concentration in water, GO membranes with different thickness can be easily fabricated via a one-time filtration process.
G2O™s patented graphene oxide technology acts as a functional coating for modifying the surface properties of existing filter media resulting in:
Higher pure water flux;
High fouling resistance;
Excellent mechanical strength;
High chemical stability;
Good thermal stability;
Low cost.

We’re going through a water shortage here in Vancouver, Canada after a long spring season which distinguished itself with a lack of rain and the introduction of a heatwave extending into summer. It is by no means equivalent to the situation in many parts of the world but it does give even those of us who are usually waterlogged some insight into what it means when there isn’t enough water.

For more insight into water crises with a special focus on the Middle East (notice Harper mentioned Israel’s former Prime Minister Shimon Peres in his commentary), I have a Feb. 24, 2014 posting (Water desalination to be researched at Oman’s newly opened Nanotechnology Laboratory at Sultan Qaboos University) and a June 25, 2013 post (Nanotechnology-enabled water resource collaboraton between Israel and Chicago).

You can check out the World Economic Forum’s Outlook on the Global Agenda 2015 here.

The Outlook on the Global Agenda 2015 features an analysis of the Top 10 trends which will preoccupy our experts for the next 12-18 months as well as the key challenges facing the world’s regions, an overview of global leadership and governance, and the emerging issues that will define our future.

G20 Water can be found here.

Graphite research at Simon Fraser University (Vancouver, Canada) and NanoXplore’s (Montréal, Canada) graphene oxide production

Graphite

Simon Fraser University (SFU) announced a partnership with Ontario’s Sheridan College and three Canadian companies (Terrella Energy Systems, Alpha Technologies, and Westport Innovations) in a research project investigating low-cost graphite thermal management products. From an April 9, 2015 SFU news release,

Simon Fraser University is partnering with Ontario’s Sheridan College, and a trio of Canadian companies, on research aimed at helping the companies to gain market advantage from improvements on low-cost graphite thermal management products.

 

Graphite is an advanced engineering material with key properties that have potential applications in green energy systems, automotive components and heating ventilating air conditioning systems.

 

The project combines expertise from SFU’s Laboratory for Alternative Energy Conversion with Sheridan’s Centre for Advanced Manufacturing and Design Technologies.

 

With $700,000 in funding from the Natural Sciences and Engineering Research Council’s (NSERC) College and Community Innovation program, the research will help accelerate the development and commercialization of this promising technology, says project lead Majid Bahrami, an associate professor in SFU’s School of Mechatronics Systems Engineering (MSE) at SFU’s Surrey campus.

 

The proposed graphite products take aim at a strategic $40 billion/year thermal management products market, Bahrami notes. 

 

Inspired by the needs of the companies, Bahrami says the project has strong potential for generating intellectual property, leading to advanced manufacturing processes as well as new, efficient graphite thermal products.

 

The companies involved include:

 

Terrella Energy Systems, which recently developed a roll-embossing process that allows high-volume, cost-effective manufacturing of micro-patterned, coated and flexible graphite sheets;

 

Alpha Technologies, a leading telecom/electronics manufacturer, which is in the process of developing next-generation ‘green’ cooling solutions for their telecom/electronics systems;

 

Westport Innovations, which is interested in integrating graphite heat exchangers in their natural gas fuel systems, such as heat exchangers for heavy-duty trucks.

 

Bahrami, who holds a Canada Research Chair in Alternative Energy Conversion Systems, expects the project will also lead to significant training and future business and employment opportunities in the manufacturing and energy industry, as well as the natural resource sector and their supply chain.

 

“This project leverages previous federal government investment into world-class testing equipment, and SFU’s strong industrial relationships and entrepreneurial culture, to realize collective benefits for students, researchers, and companies,” says Joy Johnson, SFU’s VP Research. “By working together and pooling resources, SFU and its partners will continue to generate novel green technologies and energy conversion solutions.”

 

Fast Facts:

  • The goal of the NSERC College and Community Innovation program is to increase innovation at the community and/or regional level by enabling Canadian colleges to increase their capacity to work with local companies, particularly small and medium-sized enterprises (SMEs).
  • Canada is the fifth largest exporter of raw graphite.

I have mentioned graphite here before. Generally, it’s in relation to graphite mining deposits in Ontario and Québec, which seem to have been of great interest as a source for graphene production. A Feb. 20, 2015 posting was the the latest of those mentions and, coincidentally, it features NanoXplore and graphene, the other topic noted in the head for this posting.

Graphene and NanoXplore

An April 17, 2015 news item on Azonano makes a production announcement,

Group NanoXplore Inc., a Montreal-based company specialising in the production and application of graphene and its derivative materials, announced today that it is producing Graphene Oxide in industrial quantities. The Graphene Oxide is being produced in the same 3 metric tonne per year facility used to manufacture NanoXplore’s standard graphene grades and derivative products such as a unique graphite-graphene composite suitable for anodes in Li-ion batteries.

An April 16, 2015 NanoXplore news release on MarketWired, which originated the news item, describes graphene oxide and its various uses,

Graphene Oxide (GO) is similar to graphene but with significant amounts of oxygen introduced into the graphene structure. GO, unlike graphene, can be readily mixed in water which has led people to use GO in thin films, water-based paints and inks, and biomedical applications. GO is relatively simple to synthesise on a lab scale using a modified Hummers’ method, but scale-up to industrial production is quite challenging and dangerous. This is because the Hummers’ method uses strong oxidizing agents in a highly exothermic reaction which produces toxic and explosive gas. NanoXplore has developed a completely new and different approach to producing GO based upon its proprietary graphene production platform. This novel production process is completely safe and environmentally friendly and produces GO in volumes ranging from kilogram to tonne quantities.

“NanoXplore’s ability to produce industrially useful quantities of Graphene Oxide in a safe and scalable manner is a game changer, said Dr. Soroush Nazarpour, President and CEO of NanoXplore. “Mixing graphene with standard industrially materials is the key to bringing it to industrial markets. Graphene Oxide mixes extremely well with all water based solutions, and we have received repeated customer requests for water soluble graphene over the last two years”.

It sounds exciting but it would be helpful (for someone like me, who’s ignorant about these things) to know the graphene oxide market’s size. This would help me to contextualize the excitement.

You can find out more about NanoXplore here.

Converting light to electricity at femto speeds

This is a pretty remarkable (to me anyway) piece of research on speeding up the process of converting light to electricity. From an April 14, 2015 Institute of Photonic Science press release (also on EurekAlert but dated April 15, 2015),

The efficient conversion of light into electricity plays a crucial role in many technologies, ranging from cameras to solar cells. It also forms an essential step in data communication applications, since it allows for information carried by light to be converted into electrical information that can be processed in electrical circuits. Graphene is an excellent material for ultrafast conversion of light to electrical signals, but so far it was not known how fast graphene responds to ultrashort flashes of light.

The new device that the researchers developed is capable of converting light into electricity in less than 50 femtoseconds (a twentieth of a millionth of a millionth of a second). To do this, the researchers used a combination of ultrafast pulse-shaped laser excitation and highly sensitive electrical readout. As Klaas-Jan Tielrooij comments, “the experiment uniquely combined the ultrafast pulse shaping expertise obtained from single molecule ultrafast photonics with the expertise in graphene electronics. Facilitated by graphene’s nonlinear photo-thermoelectric response, these elements enabled the observation of femtosecond photodetection response times.”

The ultrafast creation of a photovoltage in graphene is possible due to the extremely fast and efficient interaction between all conduction band carriers in graphene. This interaction leads to a rapid creation of an electron distribution with an elevated electron temperature. Thus, the energy absorbed from light is efficiently and rapidly converted into electron heat. Next, the electron heat is converted into a voltage at the interface of two graphene regions with different doping. This photo-thermoelectric effect turns out to occur almost instantaneously, thus enabling the ultrafast conversion of absorbed light into electrical signals. As Prof. van Hulst states, “it is amazing how graphene allows direct non-linear detecting of ultrafast femtosecond (fs) pulses”.

The results obtained from the findings of this work, which has been partially funded by the EC Graphene Flagship, open a new pathway towards ultra-fast optoelectronic conversion. As Prof. Koppens comments, “Graphene photodetectors keep showing fascinating performances addressing a wide range of applications”.

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

Generation of photovoltage in graphene on a femtosecond timescale through efficient carrier heating by K. J. Tielrooij, L. Piatkowski, M. Massicotte, A. Woessner, Q. Ma, Y. Lee,  K. S. Myhro, C. N. Lau, P. Jarillo-Herrero, N. F. van Hulst & F. H. L. Koppens. Nature Nanotechnology (2015) doi:10.1038/nnano.2015.54 Published online 13 April 2015

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

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.

Cute, adorable roundworms help measure nanoparticle toxicity

Caption: Low-cost experiments to test the toxicity of nanomaterials focused on populations of roundworms. Rice University scientists were able to test 20 nanomaterials in a short time, and see their method as a way to determine which nanomaterials should undergo more extensive testing. Credit: Zhong Lab/Rice University

Caption: Low-cost experiments to test the toxicity of nanomaterials focused on populations of roundworms. Rice University scientists were able to test 20 nanomaterials in a short time, and see their method as a way to determine which nanomaterials should undergo more extensive testing.
Credit: Zhong Lab/Rice University

Until now, ‘cute’ and ‘adorable’ are not words I would have associated with worms of any kind or with Rice University, for that matter. It’s amazing what a single image can do, eh?

A Feb. 3, 2015 news item on Azonano describes how roundworms have been used in research investigating the toxicity of various kinds of nanoparticles,

The lowly roundworm is the star of an ambitious Rice University project to measure the toxicity of nanoparticles.

The low-cost, high-throughput study by Rice scientists Weiwei Zhong and Qilin Li measures the effects of many types of nanoparticles not only on individual organisms but also on entire populations.

A Feb. 2, 2015 Rice University news release (also on EurekAlert), which originated the news item, provides more details about the research,

The Rice researchers tested 20 types of nanoparticles and determined that five, including the carbon-60 molecules (“buckyballs”) discovered at Rice in 1985, showed little to no toxicity.

Others were moderately or highly toxic to Caenorhabditis elegans, several generations of which the researchers observed to see the particles’ effects on their health.

The results were published by the American Chemical Society journal Environmental Sciences and Technology. They are also available on the researchers’ open-source website.

“Nanoparticles are basically new materials, and we don’t know much about what they will do to human health and the health of the ecosystem,” said Li, an associate professor of civil and environmental engineering and of materials science and nanoengineering. “There have been a lot of publications showing certain nanomaterials are more toxic than others. So before we make more products that incorporate these nanomaterials, it’s important that we understand we’re not putting anything toxic into the environment or into consumer products.

“The question is, How much cost can we bear?” she said. “It’s a long and expensive process to do a thorough toxicological study of any chemical, not just nanomaterials.” She said that due to the large variety of nanomaterials being produced at high speed and at such a large scale, there is “an urgent need for high-throughput screening techniques to prioritize which to study more extensively.”

Rice’s pilot study proves it is possible to gather a lot of toxicity data at low cost, said Zhong, an assistant professor of biosciences, who has performed extensive studies on C. elegans, particularly on their gene networks. Materials alone for each assay, including the worms and the bacteria they consumed and the culture media, cost about 50 cents, she said.

The researchers used four assays to see how worms react to nanoparticles: fitness, movement, growth and lifespan. The most sensitive assay of toxicity was fitness. In this test, the researchers mixed the nanoparticles in solutions with the bacteria that worms consume. Measuring how much bacteria they ate over time served as a measure of the worms’ “fitness.”

“If the worms’ health is affected by the nanoparticles, they reproduce less and eat less,” Zhong said. “In the fitness assay, we monitor the worms for a week. That is long enough for us to monitor toxicity effects accumulated through three generations of worms.” C. elegans has a life cycle of about three days, and since each can produce many offspring, a population that started at 50 would number more than 10,000 after a week. Such a large number of tested animals also enabled the fitness assay to be highly sensitive.

The researchers’ “QuantWorm” system allowed fast monitoring of worm fitness, movement, growth and lifespan. In fact, monitoring the worms was probably the least time-intensive part of the project. Each nanomaterial required specific preparation to make sure it was soluble and could be delivered to the worms along with the bacteria. The chemical properties of each nanomaterial also needed to be characterized in detail.

The researchers studied a representative sampling of three classes of nanoparticles: metal, metal oxides and carbon-based. “We did not do polymeric nanoparticles because the type of polymers you can possibly have is endless,” Li explained.

They examined the toxicity of each nanoparticle at four concentrations. Their results showed C-60 fullerenes, fullerol (a fullerene derivative), titanium dioxide, titanium dioxide-decorated nanotubes and cerium dioxide were the least damaging to worm populations.

Their “fitness” assay confirmed dose-dependent toxicity for carbon black, single- and multiwalled carbon nanotubes, graphene, graphene oxide, gold nanoparticles and fumed silicon dioxide.

They also determined the degree to which surface chemistry affected the toxicity of some particles. While amine-functionalized multiwalled nanotubes proved highly toxic, hydroxylated nanotubes had the least toxicity, with significant differences in fitness, body length and lifespan.

A complete and interactive toxicity chart for all of the tested materials is available online.

Zhong said the method could prove its worth as a rapid way for drug or other companies to narrow the range of nanoparticles they wish to put through more expensive, dedicated toxicology testing.

“Next, we hope to add environmental variables to the assays, for example, to mimic ultraviolet exposure or river water conditions in the solution to see how they affect toxicity,” she said. “We also want to study the biological mechanism by which some particles are toxic to worms.”

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

A multi-endpoint, high-throughput study of nanomaterial toxicity in Caenorhabditis elegans by Sang-Kyu Jung, Xiaolei Qu, Boanerges Aleman-Meza, Tianxiao Wang, Celeste Riepe, Zheng Liu, Qilin Li, and Weiwei Zhong. Environ. Sci. Technol., Just Accepted Manuscript DOI: 10.1021/es5056462 Publication Date (Web): January 22, 2015
Copyright © 2015 American Chemical Society

Nanomaterial effects on C. elegans

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This heat map indicates whether a measurement for the nanomaterial-exposed worms is higher (yellow), or lower (blue) than the control worms. Black indicates no effects from nanomaterial exposure.

Clicking on colored blocks to see detailed experimental data.

The published paper is open access but you need an American Chemical Society site registration to access it. The researchers’ site is open access.

Nanoelectronics at the University of British Columbia (UBC located in Vancouver, Canada)

Hidden in a Jan. 9, 2014 University of British Columbia (UBC) announcement abut funding from Canada’s Natural Sciences and Engineering Research Council (NSERC) was some information about a nano electronics laboratory,

  • Flexible, efficient solar-battery nano-textile, led by Peyman Servati, funded for $514,000.
  • Bio-inspired soft epidermal and wearable nanofiber electronics for wireless health monitoring, led by Peyman Servati, funded for $516,000. [emphases mine]

Peryman Servati leads FEEL, the flexible electronics and energy lab according to his faculty bio page. The two FEEL project s listed in the announcement have received a total of $1.3* (corrected to $1.03M, Jan. 30, 2014) in funding, over 1/3* (it’s closer to 1/4; corrected Jan. 30, 2014)  of the $4.3M earmarked* (spelling corrected Jan. 30, 2014) for nine UBC projects. Here’s more about the lab’s current roster of four ‘research areas’ from the Research Projects webpage,

1. Transparent Electrodes for Photovoltaic (PV) Devices:

Solar energy, as a clean and renewable resource, is heavily untapped, mainly due to the high cost (>$2 per watt) and low conversion efficiency (~20% for silicon) of today’s PV devices. This project aims at reducing the manufacturing cost of PV devices, by finding a scalable transparent electrode for replacing metal fingers or indium tin oxide (ITO) electrodes of conventional devices. We deposit nanocomposite fibers (NFs) with embedded conductive nanotubes (NTs) and nanowires (NWs) using novel electrospinning process that provides multiscale ordering and alignment in the structure of the NF mesh, similar to veins of a leaf (below). The process is scalable to substrates including plastic, paper and fabric, in a roll-to-roll manufacturing system. Challenges for integration of the NF mesh with Si and thin-film PV panels are being investigated to achieve the required properties at low cost.

2. Nanowire (NW) Growth and Device Fabrication:

Semiconductor and metallic NWs have unique electrical and optical properties not present in the bulk. We grow different NWs with controlled morphology using chemical vapour deposition and other growth techniques. We also work on integration of these nanomaterials into large area electronic devices, including transistors, strain sensors, bio-sensors, photodetectors, and solar cells. Materials of interest include Si, Ge, ZnO, and GaAs.

3. Flexible Organic Solar Cells:

Organic semiconductors can be deposited at low temperature on a variety of substrates. We investigate the aging and annealing effects in these materials and how the morphology of these semiconductors and blends change with time. The goal is to improve efficiency and stability of these devices.

4. Modeling of Nanomaterials and Nanocomposites:

We investigate the electron transport and band structure of novel electronic materials such as nanowires, nanotubes and graphene using atomistic modeling and simulation. [emphasis mine] Our work points out the delicacy of the surface properties of silicon nanowires (NWs) (below) and the dependence of electronic properties on surface composition and reconstruction. In addition, we work on developing analytical models that connect properties of single nanostrucutres to the properties of materials and devices made by using a large number of these nanostrucutures.

My guess is that the two projects which have received money are being investigated via the lab’s four ‘research areas’.

I am glad to have found this nanoeletronics laboratory. Sadly, they’re not investigating the memristors which so fascinate me but I can now say with certainty that there’s at least one laboratory in Canada researching, the world’s currently trendiest nanomaterial, graphene.

Graphene and your sex life

This is a first, as far as I know, for graphene, which is usually discussed in the context of electronics. A research team at the University of Manchester (where it was first isolated by Andre Gerim and Kostya Novoselov in 2004) has won a research grant to develop condoms made of graphere, from the Nov. 22, 2013 news item on Azonano,

Wonder material graphene faces its stiffest challenge yet – providing thinner, stronger, safer and more desirable condoms.

Dr Aravind Vijayaraghavan and his team from The University of Manchester have received a Grand Challenges Explorations grant of $100,000 (£62,123) from the Bill and Melinda Gates Foundation to develop new composite nano-materials for next-generation condoms, containing graphene.

Dr Vijayaraghavan took on a challenge that had been presented to inventors around the world– to develop new technology that would make the condom more desirable for use, which could lead to an increase in condom use.

Here’s how the challenge was presented in March 2013 (from the Develop the Next Generation of Condom challenge webpage on the Grand Challenges (the Bill & Melinda Gates Foundation) website,

Male condoms are cheap, easy to manufacture, easy to distribute, and available globally, including in resource poor settings, through numerous well developed distribution channels.  The current rate of global production is 15 billion units/year with an estimated 750 million users and a steadily growing market. …

The one major drawback to more universal use of male condoms is the lack of perceived incentive for consistent use. The primary drawback from the male perspective is that condoms decrease pleasure as compared to no condom, creating a trade-off that many men find unacceptable, particularly given that the decisions about use must be made just prior to intercourse. …

Likewise, female condoms can be an effective method for prevention of unplanned pregnancy or HIV infection, but suffer from some of the same liabilities as male condoms, require proper insertion training and are substantially more expensive than their male counterparts. …

The Challenge: 

Condoms have been in use for about 400 years yet they have undergone very little technological improvement in the past 50 years. The primary improvement has been the use of latex as the primary material and quality control measures which allow for quality testing of each individual condom. Material science and our understanding of neurobiology has undergone revolutionary transformation in the last decade yet that knowledge has not been applied to improve the product attributes of one of the most ubiquitous and potentially underutilized products on earth. New concept designs with new materials can be prototyped and tested quickly.  Large-scale human clinical trials are not required. Manufacturing capacity, marketing, and distribution channels are already in place.

We are looking for a Next Generation Condom that significantly preserves or enhances pleasure, in order to improve uptake and regular use. Additional concepts that might increase uptake include attributes that increase ease-of-use for male and female condoms, for example better packaging or designs that are easier to properly apply. In addition, attributes that address and overcome cultural barriers are also desired.  Proposals must (i) have a testable hypothesis, (ii) include an associated plan for how the idea would be tested or validated, and (iii) yield interpretable and unambiguous data in Phase I, in order to be considered for Phase II funding.

A few examples of work that would be considered for funding:

  • Application of safe new materials that may preserve or enhance sensation;
  • Development and testing of new condom shapes/designs that may provide an improved user experience;
  • Application of knowledge from other fields (e.g. neurobiology, vascular biology) to new strategies for improving condom desirability.

The project’s team leader, Dr Vijayaraghavan had a few things to say about the possibilities for this composite material (graphene and latex) they are hoping to develop (from the Nov. 21, 2013 University of Manchester news release, which originated the news item on Azonano),

Dr Vijayaraghavan said: “This composite material will be tailored to enhance the natural sensation during intercourse while using a condom, which should encourage and promote condom use.

“This will be achieved by combining the strength of graphene with the elasticity of latex, to produce a new material which can be thinner, stronger, more stretchy, safer and, perhaps most importantly, more pleasurable.”

He also comments on the impact of this project: “Since its isolation in 2004, people have wondered when graphene will be used in our daily life. Currently, people imagine using graphene in mobile-phone screens, food packaging, chemical sensors, etc.

“If this project is successful, we might have a use for graphene which will literally touch our every-day life in the most intimate way.”

I wonder who will be testing these condoms when the time comes.

For anyone who wants to know more about the graphene story, there are these postings (excerpted from my Jan. 3, 2012 posting about their then newly acquired knighthoods): regarding Geim and Novoselov’s work and their Nobel prizes, “my Oct. 7, 2010 posting, which also features a video of a levitating frog (one of Geim’s favourite science stunts) and my Nov. 26, 2010 posting features a video demonstrating how you can make your own graphene sheets.”

One final note, I posted about the Canadian Grand Challenges funding (not be contused with the US-based Bill and Melinda Gates Foundation programme) in this Nov. 21, 2013 posting.

University of Cambridge makes waves with graphene piano

The news about the graphene piano (and anti-fraud lasers, etc.) is contained in a report from the University of Cambridge’s Cambridge Innovation and Knowledge Centre (CIKC), according to a Nov. 5, 2013 news item on phys.org (Note: A link has been removed),

Two prototypes – a detection device which users lasers to fight fraud, and a piano which demonstrates the potential of printed electronics – have been unveiled by Cambridge researchers.

A detection device which uses printed lasers to identify counterfeit goods has been developed by researchers, who say that it could help to make products more resistant to fraud.

The detector is one of a number of innovations covered in a new report by the Cambridge Innovation and Knowledge Centre (CIKC), which has been developing advanced manufacturing technologies for photonics and electronics.

The same document also outlines a new method for printing graphene, showing how the one atom-thick material could be used to make cheap, printed electronics. Using a graphene-based ink, researchers have demonstrated this by creating a transparent, flexible piano.

Here’s a video about the transparent piano produced at Cambridge,

The Nov. 5, 2013 University of Cambridge news release, which originated the news item, offers details about the piano and the graphene inks used to produce it,

The printed piano meanwhile demonstrates the potential of using graphene in real applications where printed electronics might be needed – such as heart monitors and other sensors.

The research team behind it, Drs Tawfique Hasan, Felice Torrisi and Prof Andrea Ferrari, at the Cambridge Graphene Centre, have developed a graphene-based ink. Like the material itself, this has a number of interesting properties, including flexibility, optical transparency, and electrical conductivity.

Other conductive inks are made from precious metals such as silver, which makes them very expensive to produce and process, whereas graphene is both cheap, environmentally stable, and does not require much processing after printing. Graphene ink is also superior to conductive polymers in terms of cost, stability and performance.

The piano, designed in collaboration with Novalia Limited, shows off the graphene ink’s potential. The keys of the transparent piano are made from graphene-based inks, which have been printed on to a plastic film. These keys, working as electrodes, are connected to a simple electronic circuit-board, a battery and speaker. When a person touches a graphene electrode, the amount of electrical charge held in the key changes. This is then detected and redirected by the circuit to the speaker, creating the musical note.

The same research team, in collaboration with Printed Electronics Limited, has developed a flexible prototype digital display. This display uses conventional printable materials, but with a transparent, electrically conductive graphene layer on top. The graphene layer is not only a flexible but also more conductive and transparent than the conventional polymer it replaces. These simple displays can be used in a wide range of smart packaging applications such as toys, labelling and board games.

“Both of these devices show how graphene could be printed on to a whole range of surfaces, which makes it ideal for printed electronics,” Dr Hasan, the lead researcher behind the prototypes, said. For example, it might eventually be possible to print electronics on to clothing and to make wearable patches to monitor people with health conditions, such as a heart problem.”

Another potential application is cheap, printable sensors, which could be used to track luggage around an airport to ensure it is loaded on to the correct plane, or to follow products across a production and supply chain.

For anyone who’d like to see the report and get information on the other projects discussed in it just click on the title: Advanced Manufacturing Technologies for Photonics and Electronics – Exploiting Molecular and Macromolecular Materials: Final Report.

*’Unviersity in headline changed to University 11:11 am PDT Nov. 7, 2013.