07 Nov 2013
Re-closable anticorrosion containers: The capsules open when they are reduced and potassium ions migrate into the polymer shell. As soon as the corrosion comes to a halt, the polymer is oxidised, the capsules close and release potassium ions again.
A particularly ingenious remedy for the problem of rust may be available soon. Scientists from the Max-Planck-Institut für Eisenforschung GmbH in Düsseldorf and the Max Planck Institute for Polymer Research in Mainz have succeeded in making two enormous strides towards developing a self-healing anticorrosion coating. In one study, they embedded a few 100-nanometre-sized polymer capsules containing anticorrosion payloads in a coating. They applied the coating to a metal and exposed the metal to corrosion through a crack in the coating. Thereupon, the capsules opened and released the protective payloads. As soon as the corrosive attack ended, the containers closed again. In the second study, the researchers encapsulated substances in nanocontainers that can heal small cracks and holes in the protective metal coating. The researchers thereby demonstrated that the containers were chemically altered and released the healing payloads when the corrosion process started. The containers then closed again at the end of the corrosive attack.
Human and animal skin is exemplary in many respects. Materials scientists are impressed above all by the way in which it heals itself when damaged. They would like to endow anticorrosion coatings with this very capacity, so that fine cracks and small holes in coatings do not spell disaster in the short or long term for the underlying metal. “We have made two breakthroughs in the quest for intelligent corrosion protection,” reports Michael Rohwerder, Leader of a Research Group at the Max-Planck-Institut für Eisenforschung.
Together with their colleagues from the Max Planck Institute for Polymer Research, the Düsseldorf-based researchers tested capsules made from the conductive polymer polyaniline as containers for anticorrosive substances. They had decorated the nanocapsules with metal nanoparticles to generate suitable electrical contact between the containers and the metal to which they applied the capsules as components in a coating. Through a defect in the protective coating, they exposed the metal to corrosion by trickling a drop of salty water onto the opening in the protective coating. The corrosive attack, however, had no effect, as the walls of the polymer capsules became porous, allowing the substances contained in them to escape, which then blocked the oxygen reduction process.
The electrochemical potential is the most reliable key for opening the capsules
“What is crucial here is to select the correct signal for opening the capsule wall,” says Michael Rohwerder. The capsules can thus be opened purely mechanically when the protective coating is scratched. Or they can react to a rising pH value, which can accompany the process of corrosion. However, the Max Planck team opted to exploit the electrochemical potential as a capsule opener that punctured the polyaniline cover through a process of chemical conversion. “This potential always falls when corrosion starts,” explains Rohwerder. “So it provides the most reliable signal for the capsules to open.” Moreover, electrical contact is required for the capsules to recognise the electrochemical alarm as well. This is provided by the metal nanoparticles between the capsule wall and the metal. The capsules detect when the corrosion has stopped through the same information channel, as the potential rises constantly at this point. The capsule wall then restructures itself and the pores are re-sealed.
The containers, in which the researchers enclosed payloads can be used to form a polymer skin. These payloads can polymerise in a defect and seal the crack or hole. However, in this study the scientists did not apply the capsules to a metal using a coating to test them for corrosion. They replicated the chemical conditions that exist at the beginning and end of the corrosion process with reducing and oxidising substances and opened or closed the capsules in this way. “We were able to repeat this redox process with the polyaniline capsules over 80 times,” says Daniel Crespy, a Research Group Leader at the Max Planck Institute for Polymer Research, who supervised the study.
Oily fluids can be encapsulated in a miniemulsion
The fact that the healing substances can be encapsulated in a targeted way is of particular interest from the chemist’s perspective. This is made possible by a technique developed by researchers working with Katharina Landfester at the Max Planck Institute for Polymer Research in Mainz. They produce an emulsion from an aqueous solution, in which drops of oil float. A process that only functions to a limited extent with milk – after a while the cream accumulates on the top – was perfected by the chemists. In their miniemulsion, not only are the drops of oil similarly small in size, but they remain, thanks to a few chemical tricks, almost completely stable.
Before Daniel Crespy and his colleagues finely emulsify the oily fluid in the aqueous solution by mixing it and using ultrasound, they add the components for the polymer capsules to it. The components only react to produce long chain molecules when the chemists trickle another chemical ingredient into the prepared emulsion, which dissolves in water and triggers the polymerisation precisely on the surface of the oil drops. “This is how we can encapsulate oily fluids in an aqueous environment,” says Daniel Crespy. However, despite sounding like a simple recipe, the finer details of process are actually very difficult to implement. During the polymerisation, the chemical milieu of the emulsion changes so that the drops of oil tend to aggregate and would normally accumulate on top of the water. “But we found a way of stabilising the emulsion,” says Crespy.
The anticorrosion substances must be made more effective
Moreover, it is not exactly easy to prove that the capsules only release the remedy for healing the defects in a coating when necessary. To this end, the researchers in Mainz had to isolate the capsules after each step, displace them with suitable solvents and examine them with the help of nuclear magnetic resonance spectroscopy, which provided information about the volumes of the substances contained in the capsules.
In the two recent studies, the team of researchers from Düsseldorf and Mainz endowed the nanocapsules with some of the functions that a self-healing corrosion coating would have to provide. “We now want to enclose the healing substances and the anticorrosion substances together in the same capsules,” says Crespy, as only both substances combined can provide comprehensive protection against the destruction caused by rust. Whereas the anticorrosion substances quickly stem the corrosion, like the initial halting of the blood flow in the case of injury, the healing substances restore the enduring anticorrosive effect of the coating. However, like a healing wound, they need more time to do their work. “Up to now, it has not been possible to encapsulate both substances under the same chemical conditions,” says Daniel Crespy. This is what he and his colleagues would like to achieve.
Michael Rohwerder has also identified two further challenges that must still be overcome before the self-healing anticorrosion system is complete. “First, we must identify inhibiting substances which are as effective, for example, as chromates,” says the scientist. Chromates still set the standard in terms of anticorrosion coatings at present; however, they are being banned in an increasing number of applications due to their toxicity. “Second, we must ensure that the healing substances reach a defect faster and in greater quantities,” says Rohwerder. Up to now, they have been held back by the fact that they are not very water-soluble; corrosion, however, only occurs when a defect is exposed to water. If the researchers succeed in making progress on these issues, it is entirely possible that metal coatings will be the equal of living skin when it comes to powers of self-healing.
Explore further: A self-healing protective coating for concrete
Animal and plant cells are prominent examples of how nature constructs ever-larger units in a targeted, preprogrammed manner using molecules as building blocks. In nanotechnology, scientists mimic this ‘bottom-up‘ technique by using the ability of suitably structured nano materials to ‘self-assemble‘ into higher order architectures. Applying this concept, polymer scientists from Bayreuth, Aachen, Jena, Mainz, and Helsinki have recently published an article in the prestigious journal Nature that describes a new principle for the self-assembly of patterned nanoparticles. This principle may have important implications for the fundamental understanding of such processes as well as future technologies.
Animal and plant cells are prominent examples of how nature constructs ever-larger units in a targeted, preprogrammed manner using molecules as building blocks. In nanotechnology, scientists mimic this ‘bottom-up’ technique by using the ability of suitably structured nano materials to ‘self-assemble’ into higher order architectures. Applying this concept, polymer scientists from Bayreuth, Aachen, Jena, Mainz, and Helsinki have recently published an article in the prestigious journal Nature that describes a new principle for the self-assembly of patterned nanoparticles. This principle may have important implications for the fundamental understanding of such processes as well as future technologies.
However, the process of self-assembly does not end with the nanoparticles. If the nanoparticles formed by each type of macromolecule were left to their own, spherical superstructures would result on the one hand and linear superstructures on the other. Müller’s team has developed and implemented a different approach. The nanoparticles with one and two bonding sites are mixed so that they aggregate together into a completely new superstructure in a process of co-assembly. In the final superstructure, the nanoparticles originating from the A-B-C molecules and nanoparticles formed by the A-D-C molecules alternate in a precisely defined pattern.
When viewed under a transmission electron microscope, the new superstructure bears a strong resemblance to a caterpillar larva, because it also consists of a series of clearly separate, regularly ordered sections. Müller’s research team has thus coined the term “caterpillar micelles” for such co-assembled superstructures.
The research findings recently published in Nature represent a breakthrough in the field of hierarchical structuring and nano-engineering as it allows creating new materials by self-assemble preprogrammed particles. This could be a game changer, because so far only top-down procedures, i.e., extracting a microstructure from a larger complex, are widely accepted structuring processes. “The limitations of this technique will become all too apparent in the near future,” explained Müller. “Only rarely is it possible to generate complex structures in the nanometer range.”
However, a bottom-up principle of self-assembly based on that employed in nature could well represent the best way forward. One factor that makes this particularly attractive is the large number of macromolecules, which are readily available as building blocks. They can be used to incorporate specific properties in the resultant superstructures, such as sensitivity to environmental stimuli (e.g. temperature, light, electric and magnetic fields, etc.) or give them the ability to be switched on and off at will. Possible applications include nanolithography and the delivery of drugs in which the time and site of release of active substances can be preprogrammed. Here, the similarity to the structural principles of animal and plant cells becomes apparent again, where various properties are compartmentalized into areas of limited space.
The macromolecules carrying diverse functional segments can be hundreds of times smaller than a micrometer. The superstructures that such macromolecules produce have correspondingly high resolution. “Future technologies – such as tailor-made artificial cells, transistors, or components for micro/nano-robotics – may benefit significantly from this particularly delicate structuring,” explained Müller. “The research findings we published in Nature do not yet have any immediate real-world applications. Nevertheless, the better we understand bottom-up processes starting with molecules in the nanometer range and moving on to the higher hierarchical levels in the micrometer range, the more likely future technologies will be within our grasp.” The caterpillar micelles are in no way the only superstructures that can be produced with the self-assembling nanoparticles. “Such soft nanoparticles can be combined with inorganic or biological nano- and microparticles to create previously unknown materials with specific functions. The number of possible combinations is practically endless,” concluded Müller.
07 Nov 2013
SAN MARCOS, Texas, Nov. 7, 2013 /PRNewswire/ – Quantum Materials Corp. announced today that it has provided Tetrapod Quantum Dots (TQD) to an advanced medical device manufacturer to optimize performance of an “engineered spectrum” quantum dot-enabled light source to better provide useful data to researchers and practitioners that has not been easily discernible until now.
David Doderer, Vice President of R&D, explained, “We are fulfilling specific requests for tetrapod quantum dots, in this case, to create tailored light for investigation of tissue. Differences between healthy and suspect tissue often can be better identified if the available fluorophores’ color combination is engineered for either true representation of color, or emphasized in the visible spectrum depending on the tissue type. I think our bespoke tetrapod quantum dots provide the depth of data necessary to highlight subtle differences that researchers and healthcare professionals need to efficiently understand disease and devise effective treatments.”
To achieve efficient healthcare in an increasingly demanding marketplace, the ability to get actionable information is crucial. Medical diagnostic assays currently count in the multi-millions per year and per country, and differences in tissues types at the cellular level are critically important for accuracy in results. Conventional organic dyes and other types of fluorophores are currently used for luminescence in assays by researchers, but they have limitations sometimes preventing clear distinctions in reading the data. Broad data sets can tend to obscure patterns that might become clear by removing these uncertainties.
Tetrapod quantum dots address this issue well for biochemical detection and biomedical device application by providing a broad array of colors, which translates to increased number of pieces in the data set, and also precise tune-ability and stability for high contrast and distinctive identification certainty. For biochemical detection, most typically in a rapid assay that provides a breadth of data in a single test kit, Quantum Materials has begun conversations with biotech researchers and companies needing narrow color emissions to provide clear identification when identifying particular targets by attaching to the desired organism or cell type when specifically functionalized.
As part of this effort, the Company is developing a suitable TQD film for medical devices while maintaining consistency in both uniformity and scalability. The Company believes this technology, one of several under review, could also successfully translate into Tetrapod Quantum Dot film applications such as general light applications, electronic displays and quantum dot solar cells.
Quantum Materials Corp. manufactures Tetrapod Quantum Dots for use in medical, display, solar energy and lighting applications through patent pending continuous-flow production process. Quantum dot semiconductors enable a new level of engineered performance in a wide array of established consumer and industrial products. QMC’s volume manufacturing methods enable consistent QD quality and scalable cost reductions to drive innovative discovery to commercial success.
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This press release contains forward-looking statements that involve risks and uncertainties concerning business, products, and financial results. Actual results may differ materially from the results predicted. More information about potential risk factors that could affect our business, products, and financial results are included in our annual report and in reports subsequently filed with the Securities and Exchange Commission (“SEC”). All documents are available through the SEC’s EDGAR System at http://www.sec.gov/ or www.QMCdots.com. We hereby disclaim any obligation to publicly update the information provided above, including forward-looking statements, to reflect subsequent events or circumstances.
Materials science and nanotechnology students at the University of Alberta have recently joined more than 70 universities across the world in becoming members of the internationally known Materials Research Society (MRS).
The newly established MRS chapter at the U of A is the first in Canada and will set an example for other universities in the country to follow, according to its founding member.
Rokib Hassan, PhD student and president of the U of A MRS chapter, said it’s becoming increasingly important for students to get involved with these global organizations, as they help foster a sense of leadership in their fields.
“What happens is the (students can) boost their research and commit to working with the materials research or nanotechnology communities,” he said.
“They’re trying to create a field or a platform for their students, so that they can become more passionate to pursue their interests or their research in the areas of materials research or nanotechnology.”
The idea to establish a chapter at the U of A came to Hassan when he travelled to Cancun for an MRS conference and saw the types of schools that were represented — some of the largest, most prestigious American universities had established chapters, he said, but no Canadian schools.
“I was quite shocked when I went there,” Hassan said. “I started thinking, ‘Why not from Canada?’ We are just beside the U.S., and if the U.S. are leading all the (research), why not Canada?”
Hassan said when he began the process of founding the U of A chapter, he received positive responses from the community, quickly gathering interested undergraduate students, graduate students and faculty members in a matter of weeks.
Going forward, the new chapter aims to host its own symposium next year, and eventually create undergraduate funding and a summer research program. Hassan said the chapter, like the ever-changing fields of nanotechnology and materials science, is looking to build the future.
“In the future, everything is coming up to the materials science and nanotechnology, if you think about making all the devices for your iPhone or smartphone,” he said.“Everything is coming into the materials science and nanotechnology (area).”
Researchers from the National Institute of Standards and Technology (NIST) have joined with an international team to engineer and measure a potentially important new class of nanostructured materials for microwave and advanced communication devices.
Based on NIST’s measurements, the new materials—a family of multilayered crystalline sandwiches—might enable a whole new class of compact, high-performance, high-efficiency components for devices such as cellular phones.*
Not a brick wall. Electron microscope image of a cross section of the newly characterized tunable microwave dielectric clearly shows the thick layers of strontium titanate “bricks” separated by thin “mortar lines” of strontium oxide that help promote the largely defect-free growth of the bricks.
Credit: TEM image courtesy David Mueller. Color added for clarity by Nathan Orloff. high resolution version
“These materials are an excellent example of what the Materials Genome Initiative refers to as ‘materials-by-design’,” says NIST physicist James Booth, one of the lead researchers. “Materials science is getting better and better at engineering complex structures at an atomic scale to create materials with previously unheard-of properties.”
The new multilayer crystals are so-called “tunable dielectrics,” the heart of electronic devices that, for example, enable cell phones to tune to a precise frequency, picking a unique signal out of the welter of possible ones.
Tunable dielectrics that work well in the microwave range and beyond—modern communications applications typically use frequencies around a few gigahertz—have been hard to make, according to NIST materials scientist Nathan Orloff. “People have created tunable microwave dielectrics for decades, but they’ve always used up way too much power.” These new materials work well up to 100 GHz, opening the door for the next generation of devices for advanced communications.
Modern cellphone dielectrics use materials that suffer from misplaced or missing atoms called “defects” within their crystal structure, which interfere with the dielectric properties and lead to power loss. One major feature of the new materials, says Orloff, is that they self-correct, reducing the effect of defects in the part of the crystal where it counts. “We refer to this material as having ‘perfect faults’,” he says. “When it’s being grown, one portion accommodates defects without affecting the good parts of the crystal. It’s able to correct itself and create perfect dielectric bricks that result in the rare combination of high tuning and low loss.”
The new material has layers of strontium oxide, believed to be responsible for the self-correcting feature, separating a variable number of layers of strontium titanate. Strontium titanate on its own is normally a pretty stable dielectric—not really tunable at all—but another bit of nanostructure wizardry solves that. The sandwich layers are grown as a thin crystalline film on top of a substrate material with a mismatched crystal spacing that produces strain within the strontium titanate structure that makes it a less stable dielectric—but one that can be tuned. “It’s like putting a queen-sized sheet on a king-sized bed,” says Orloff. “The combination of strain with defect control leads to the unique electronic properties.”
One key discovery by the research team was that, in addition to adding strain to the crystal sandwich, adding additional layers of strontium titanate in between the strontium oxide layers increased the room-temperature “tunability” performance of the structure, providing a new mechanism to control the material response. The material they reported on recently in the journal Nature has six layers of strontium titanate between each strontium oxide layer.
The new sandwich material performs so well as a tunable dielectric, over such a broad range of frequencies, that the NIST team led by Booth had to develop a new measurement technique—an array of test structures fabricated on top of the test film—just to measure its electronic characteristics. “We were able to characterize the performance of these materials as a function of frequency running from 10 hertz all the way up to 125 gigahertz. That’s the equivalent of measuring wavelengths from kilometers down to microns all with the same experimental set-up,” says Orloff, adding, “This material has a much lower loss and a much higher tunability for a given applied field then any material that we have seen.”
An international team of researchers contributed to the recent paper, representing, in addition to NIST, Cornell University, the University of Maryland, Pennsylvania State University, the Institute of Physics ASCR (Czech Republic), Universitat Politècnica de Catalunya (Spain), the Kavli Institute at Cornell for Nanoscale Science, Oak Ridge National Laboratory, the Leibniz Institute for Crystal Growth (Germany), The University of Texas at Austin and Temple University.
Contact: Michael Baum 301-975-2763
For additional perspective, see the Cornell University news story, “Tunable antenna could end dropped cell phone calls” at www.news.cornell.edu/stories/2013/10/tunable-antenna-could-end-dropped-cell-phone-calls. For more on the MGI at NIST, see www.nist.gov/mgi/index.cfm.
06 Nov 2013
(Nanowerk Spotlight) Freshwater looks like it will become the oil of the 21st century – scarce, expensive and fought over. While over 70 per cent of the Earth’s surface is covered by water, most of it is unusable for human consumption.
According to the Government of Canada’s Environment Department (take a look at their Freshwater Website – a great resource for facts and all kinds of aspects about water), freshwater lakes, rivers and underground aquifers represent only 2.5 per cent of the world’s total freshwater supply. Unfortunately, in addition to being scarce, freshwater is also very unevenly distributed.
The United Nations has compared water consumption with its availability and has predicted that by the middle of this century between 2 billion and 7 billion people will be faced with water scarcity. It gets worse: In the developing countries, 80 per cent of illnesses are water-related. Due to the shortage of safe drinking water in much of the world, there are 3.3 million deaths every year from diarrheal diseases caused by E. coli, salmonella and cholera bacterial infections, and from parasites and viral pathogens. In fact, between 1990 and 2000, more children died of diarrhea than all the people killed in armed conflicts since the Second World War.
The use of nanotechnologies in four key water industry segments – monitoring, desalinization, purification and wastewater treatment – could play a large role in averting the coming water crisis. But hoping that the ‘magic’ of nanotechnology will solve all water problems is naive – the basic problems of accessibility to technologies, affordability, and fair distribution still need to be solved.
So nanotechnologies, or technology in general, should not be seen as a cure all: a lot of problems arise from the way we chose to live (in the rich countries, where we have a choice) and the preferences we set as politicians, producers and consumers. It is also important to note that many conventional technologies already exist that effectively remove bacteria, viruses, coliforms, and other contaminants from water; water desalination is a proven technology; and wastewater treatment plants do exist.
Some of these solutions are expensive; some are affordable and can be produced locally. With enough political will, a lot of funding, and smart and sustained logistical efforts all these technologies could be made available where needed.
Saudia Arabia, for instance, produces 70 per cent of its drinking water from desalination plants (no nanotechnology involved). However, one industrial-scale plant costs roughly one billion dollars and one cubic meter of water costs a bit over $1 to produce.
As for water purification, a review of the literature suggests that several technical challenges remain with regards to the cost and effectiveness of removal of certain contaminants in a manner that meets the needs of people in developing countries. That’s where nanotechnology comes in because it could increase the effectiveness of existing water treatment solutions and, so claim the proponents, be made available at a much lower cost.
There is a good discussion of these issues in the Meridian Institute‘s Background Paper for the International Workshop on Nanotechnology, Water, and Development (the event took place in October 2006 in Chennai, India). This report is especially helpful to understand what the conventional water treatment technologies are and where nanotechnology-based technologies could improve upon them. In case you want to read up on this issue, there is another good report from Meridian that looks especially at water filtration nanotechnologies (Nanotechnology, Water, and Development)
It is misleading, though, to suggest that nanotechnologies will magically change this picture anytime soon. Almost all proponents of nanotechnology-based water treatment technologies claim that nanotech will make it more affordable. That may be the case some time in the future. You need to make a big leap of faith to buy this argument today.
Firstly, most nanotechnology-based applications are still in the lab or have barely made it to the fab. None of them has been scaled up to industrial levels yet – a major prerequisite to bring prices down – and by looking around at what nanotech products are commercially available it appears that some even claim a price premium.
Not a single product out there advertises to be cheaper because it is nanotechnology-enabled. Let’s also be clear that all nanotechnology applications proposed for water applications today are evolutionary, i.e. they will offer some improvements over existing devices and applications, not a revolutionary new way of doing things.
In case you only vaguely remember your Economics 101 class, here is how profit-oriented companies operate – they will introduce new materials or technologies in their products or production processes for basically one of two reasons: 1) the new technology allows the company to offer an improved product which could be sold at a higher price (which could, but doesn’t have to, result in a higher margin, depending to what degree production costs rise) and/or gives it a performance advantage over the competition; 2) the new technology allows the company to reduce its production costs (sometimes even while improving product quality and features at the same time), in which case it could offer the product at the same price and achieve a higher margin, or, if competition is tough, reduce its price.
Reason one clearly is not an option for improving water quality around the globe because it would make things even more expensive than they are today. That leaves reason two: companies need an economic incentive to introduce nanotechnology in their applications. As with all other areas (especially in energy) this industrial scale-up needs to happen for more effective nanotechnology-enabled products, that could help solve real problems, to hit the market en masse (and not just make your car’s paint more scratch resistant or you golf ball fly straighter).
“Before these technologies can make the leap from the laboratory to the mass market, they will need to clear the hurdles of public acceptance and economic feasibility” says Lynn Foster, the Emerging Technologies Director of Greenberg Traurig and co-author of a recent article in Nanotechnology Law & Business (“Nanotechnology in the Water Industry”). “
Many of these applications are still in their infancy and will require further testing to prove their reliability. Furthermore, implementing many of these technologies will require additional capital investment by existing water treatment centers to upgrade equipment and train personnel. However, though the proponents of nanotechnology face a challenge in convincing private and public entities to incur the up-front costs of adopting these new water purification technologies, nanotechnology holds out the promise of long-term benefits in the form of decreased costs of purifying the world’s water supplies and the enormous savings that would accompany reliable access to potable water in those areas of the world that currently suffer from lack of adequate drinking water and basic sanitation services.”
A very good example of how tricky the introduction of new technologies is, just look at your own personal behavior. You can buy nanotechnology-based water filters for your home today, for instance Brita filters which you just screw onto your kitchen tap. That gives you perfectly good, safe and fine-tasting drinking water. Chances are, though, that your fridge is stocked with bottled water; an alternative that, although you couldn’t taste the difference to filtered tap water, is more expensive and ecologically damaging.
Could it be that you are influenced by the ubiquitous ads for the oh-so-healthy products of the bottled water industry? If you bought Brita and other companies’ filters you would support companies like Argonide that push nanotechnology in their products. If you buy bottled water you support companies like Coca Cola. Brita, Argonide et. al. can’t afford the huge advertising budgets of the food giants but an informed consumer shouldn’t be misled by advertising anyway (nice theory…).
Let’s just say we agree that water filters are a better choice than plastic bottles. What then will it take for a consumer society to change its behavior and switch to the beneficial technology? Which in turn would bring the price of this technology down and help spread its reach.
In conclusion, there are three points to make. The first is that conventional technology and political will today could solve a lot, if not all, of the water problems the world is facing. At considerable cost. The second is that nanotechnologies, in theory, could make it easier to solve these problems if the hurdle of commercialization can be overcome; because as long as nanotechnology-enabled products are more expensive than their non-nanotech alternatives, we’ll face the some problems that we already are having today.
And lastly, no matter how promising a new technology is, if entrenched economic interests have different goals, it is hard to reap the benefits of the new.
By Michael Berger, Copyright Nanowerk LLC Read more: http://www.nanowerk.com/spotlight/spotid=2372.php#ixzz2jt9w7tUD
ChipCare Corp., a spin-off company from University of Toronto in Canada developing hand-held diagnostics devices to replace fixed expensive lab equipment, secured $2.05 million in early stage angel financing.
The deal combines investments from university, private-sector, and Canadian government sources, according to an announcement by Grand Challenges Canada, a government-financed organization supporting medical innovations in Canada and the third world.
Prototype cell analyzer (ChipCare Corp.)
The company’s first product is a hand-held blood testing device built with microfluidics or lab-on-a-chip technology. The device, resembling a supermarket bar code scanner, needs only a tiny blood sample, but can test the sample for HIV in a few minutes. Most HIV tests today require analysis by a flow cytometer, an expensive electronic lab device that performs a variety of medical diagnostics.
Research for the cell analyzer, as the device is called by ChipCare, was conducted in the University of Toronto engineering lab of Stewart Aitchison that investigates optical signal processing for applications in biomedical and physical sciences. Among the lab’s specialties is integrated biosensors for lab-on-chip applications.
The cell analyzer is the work of James Dou, a graduate student in Aitchison’s lab, and the co-founder of ChipCare with Lu Chen, a postdoctoral researcher in the lab. Dou envisioned the cell analyzer in his master’s thesis at University of Toronto and since 2006 has been leading the project to commercialize the technology.
Dou received a Heffernan Fellowship from the university to commercialize the research and was awarded with Aitchison one of the university’s 2012 inventors of the year for their work with the device. He serves as ChipCare’s chief technologist, while Chen is the company’s product development director.
Grand Challenges Canada is leading the financial round, with contributions from Maple Leaf Angels, MaRS Innovation, and University of Toronto. Maple Leaf Angels is a group of high net worth private individuals who invest in seed and early stage technology companies. MaRS Innovation is a consortium of 15 Canadian universities, teaching hospitals, and research institutes that collaborate on commercializing research findings. Specific contributions from these sources were not disclosed.
The proceeds of the round are expected to support the next three years of the device’s development including refinement of its functionality, a more robust prototype, and a reduction in its cost as it moves closer to commercial scale. While the device is first expected to analyze blood samples for HIV, ChipCare plans to expand its diagnostic functions to cover other diseases, such as tuberculosis and malaria.
This feature news is part of Singapore International Water Week’s (SIWW) series of one-on-one interviews with global water industry leaders, Conversations with Water Leaders. In this edition, HE Dr Abdulrahman M Al-Ibrahim, Governor of Saline Water Conversion Corporation (SWCC), Kingdom of Saudi Arabia, shares with OOSKAnews correspondent, Renee Martin-Nagle, his thoughts on renewable energy for desalination and the provision of water for all.
HE Dr Abdulrahman M Al-Ibrahim elaborates on how he combined desalination with renewable energy, SWCC’s strive towards operational excellence, environmental responsibility and more.
To start, would you mind speaking about the focus that is being placed by Saudi Arabia on solar energy for desalination?
Certainly. Recently the SWCC board of directors adopted a series of strategic goals, one of which is operational excellence. Part of that operational excellence is to enrich our portfolio of energies, including renewable energies like solar, photovoltaic, thermal, wind, geothermal, and other renewable energies. In the recent past we initiated construction of the first solar desalination plant in Al-Khafji that will produce 30,000 cubic meters per day of desalinated water and is operated by photovoltaic cells with an RO [reverse osmosis] desalination system. The King Abdulaziz City for Science and Technology (KACST) was the leader of this program, and we partnered with KACST to build, manage and maintain the plant throughout its life. We are investigating a more rigorous program to produce around 300,000 cubic metres per day with renewable energies. So, to summarize, renewable energy is not a luxury for us. It is part of our strategy, and it is a means to enrich our portfolio of energy so that we will have the right mix for our operation.
The Kingdom of Saudi Arabia has the most installed capacity for desalination in the world and currently it is planning to export its technical know-how regionally and internationally. Image: Power Insider Asia
My understanding is that the energy output of solar may not be adequate for some of the older desal technologies such as multi-stage flash. Is that why you are using it for reverse osmosis?
I’m sure if we want to couple renewable energy with desalination, we will have to look at different technologies and pick the ones that are the best match, which could be Multi-Effect Distillation (MED), RO hybrid or Tri-hybrid. To start with, we selected RO for the Al-Khafji plant because as a rule of thumb, RO requires the least energy, but on the west coast we are investigating other technologies, such as Tri-hybrid. It’s partially an MED as well as an RO plant with Nano-Filtration (NF) and other means. We are devoting R&D to finding the right technologies to adapt to the renewable energies available locally.
All the projects I am currently overseeing are my favorite, but I’ll tell you about my dream. My dream is to have a highly reliable and very efficient desalination plant that becomes a model not just for our kingdom, Saudi Arabia, but a model worldwide.
Saudi Arabia has the most installed capacity for desalination in the world. As you do research and gather technologies, does the Kingdom intend to become an exporter of technology as well as an importer?
Yes, we do. For the past 30 or 40 years, the ultimate goal of SWCC was to produce desalinated water to meet the needs of the Kingdom. Now we want to go beyond that goal and export know-how regionally as well as internationally. Our roadmap is to be able to develop know-how, intellectual property, prototypes and patents locally. In the past three or four years, we have come to own some patents, and we want to double that number in the next couple of years.
Would you give me an example of the latest technologies that you are exploring?
Sure. SWCC, together with the Water Re-use Promotion Center of Japan and Sasakura Company, conducted a joint research study to develop a fully integrated NF/SWRO/MED tri-hybrid system. This desalination system enabled us to reduce significantly the water production cost per unit, which we see as a break-through. Subsequently, a number of patents have been registered in Saudi Arabia, Japan and China.
How did you personally get involved in desalination?
I’m a graduate of the mechanical engineering program in Jeddah, in the area of thermal science, and at that time, we were required to study two courses in desalination and do two internships in industrial facilities. My second internship was in a small Multi-Stage Flash (MSF) plant in Jeddah, and, after doing a research project, it became my dream to combine desal with renewable energy. Luckily, in around 1986, I also worked with a very small solar desalination plant in Yanbu that used a technology called thermal freezing, where you freeze the seawater using an absorption system to reach almost zero degrees and then recover fresh water from the system. I went on to get a Master’s degree and a PhD in thermal engineering and renewable energies, and moved my expertise to energy efficiency. After 20 or 30 years, combining desal and renewable energy is becoming a reality instead of a pilot.
What changes have you seen in the past 20-25 years since you first got involved with desal?
Almost two months ago we launched a new plant in Jeddah called Jeddah RO-3 that operates on reverse osmosis. This plant was built on a site where a thermal plant was in operation since the late 70s and produced 40,000 cubic metres. We demolished the old plant and built a new one on the same footprint that now produces 240,000 cubic metres. So in a 25- or 30-year span we were able to increase production by six times over.
The second thing is our local expertise here in Saudi Arabia. In the past, we had to hire multiple international companies to be able to operate our plants and produce the water. In those days, you would seldom find a Saudi person operating or maintaining the plant. Now, Saudi locals perform 91 per cent of all our operations as engineers, technicians and managers who understand the technologies and who are able to diagnose and fix problems. We admire and respect all international expertise and we utilize it to the best that we can. At the same time, we feel that we are ready now to stretch our arms to regional and international markets and spread our expertise in terms of technologies, IP and manufacturing facilities. The Kingdom of Saudi Arabia has invested in desal, and we hope that it will add value to our GDP.
What will be the criteria for choosing desal technologies in the future?
Two factors will be the criteria for selecting technology — energy consumption and reliability. Membrane technology will be able to attain energy efficiency very well. However, we need to be able to assist it with more devices to make it more reliable. If the price of energy is important in your area, then you need to give it more weight. If reliability is more of an issue, then you give it more weight.
As much as we care about producing water, we also care about the environment, for multiple reasons. The primary factor is that we live in and share the same area, so we need to protect the environment next to us. Secondly, our intake is affected by its surrounding area, and therefore we should not spoil the water next to the plant itself.
What is the problem with membrane reliability?
Membrane technology is very sensitive to the quality of water it receives. For example, if there is red tide, or an algae bloom, or any other material in the seawater, such as a high Silt Density Index (SDI), you would need to shut down the plant to preserve your membrane, or augment your plant with pre-treatment facilities to clean the water before you introduce it to the membrane. On the other hand, although thermal is very expensive and utilizes maybe two or three times as much energy as membrane technology, it may tolerate any water. Also, to be able to build membrane technology, you need to have a pilot plant for a year or two at the same location and study the water carefully to select the most appropriate pre-treatment process.
SWCC uses seawater for its operations. What you do with the brine that is left over?
As much as we care about producing water, we also care about the environment, for multiple reasons. The primary factor is that we live in and share the same area, so we need to protect the environment next to us. Secondly, our intake is affected by its surrounding area, and therefore we should not spoil the water next to the plant itself. We perform multiple procedures so as not to intervene with the eco-system next to the plant. We do this at SWCC and in any saline water industrial facility. For example, one standard procedure is to withdraw up to ten times the amount of water that you intend to desalinate, and discharge the extra with the brine to reduce the effect of high temperature or high salinity. We also measure the temperature of the intake and the discharged brine to make sure we protect the ecosystem next to the plant.
The newly commissioned plant in Jeddah – the Jeddah RO-3 – was built with multiple advanced measures to protect the environment –not only water intake and the brine but also energy efficiency within the building. We reduced the energy consumption through the cooling grade and the lighting system, and we are applying to multiple professional organizations to receive certificates of energy efficiency in the new building as well as in the plant.
There is a desalination plant that is constructed on a floating platform in Yanbu. Would you describe it?
It’s one of the unique features that we have in Saudi Arabia. We have two barges, each one able to produce 25,000 cubic metres per day, that move on the west coast from Yanbu to Shuaibah to Shuqaiq or anywhere else to augment the production of a desal plant. So we move the barge from one location to the other according to the needs that may occur. The barges are stand-alone, with their own power supplied by liquid fuel.
I always hesitate to ask a parent which of his children is the favorite, but would you tell me if there are any projects that are your favorite?
All the projects I am currently overseeing are my favorite, but I’ll tell you about my dream. My dream is to have a highly reliable and very efficient desalination plant that becomes a model not just for our kingdom, Saudi Arabia, but a model worldwide. I want it to become a benchmark.
What final message would you like to leave with our readers?
The people of Saudi Arabia and the employees of the Saline Water Conversion Corporation are eager to produce water to serve the needs of anyone who lives on the planet earth. And we’re extremely happy to share our technologies and information with anyone who shares the same interest values. We believe, as the people of Saudi Arabia, that water is a commodity that should be made available to anyone who lives on the planet, regardless of his faith, regardless of his type, whether he’s human or animal or anyone else. The commercial aspect is an instrument to enable us to provide water that is necessary for life on earth. I totally believe that water is a value-related issue. It’s not a luxury item that needs to be looked at from a commercial business point of view. It’s something that has to be made available for everyone, so that anyone who lives on earth will have adequate quantity and quality of water.
31 Oct 2013
Absorption is especially critical for nano-sized structures at the interface between two energy barriers called quantum wells, in which the movement of charge carriers is confined to two-dimensions. Now, for the first time, a simple law of light absorption for 2D semiconductors has been demonstrated.
Working with ultrathin membranes of the semiconductor indium arsenide, a team of researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) has discovered a quantum unit of photon absorption, which they have dubbed “AQ,” that should be general to all 2D semiconductors, including compound semiconductors of the III-V family that are favored for solar films and optoelectronic devices. This discovery not only provides new insight into the optical properties of 2D semiconductors and quantum wells, it should also open doors to exotic new optoelectronic and photonic technologies.
“We used free-standing indium arsenide membranes down to three nanometers in thickness as a model material system to accurately probe the absorption properties of 2D semiconductors as a function of membrane thickness and electron band structure,” says Ali Javey, a faculty scientist in Berkeley Lab’s Materials Sciences Division and a professor of electrical engineering and computer science at the University of California (UC) Berkeley. “We discovered that the magnitude of step-wise absorptance in these materials is independent of thickness and band structure details.”
Javey is one of two corresponding authors of a paper describing this research in the Proceedings of the National Academy of Sciences (PNAS). The paper is titled “Quantum of optical absorption in two-dimensional semiconductors.” Eli Yablonovitch, an electrical engineer who also holds joint appointments with Berkeley Lab and UC Berkeley, is the other corresponding author. Co-authors are Hui Fang, Hans Bechtel, Elena Plis, Michael Martin and Sanjay Krishna.
Previous work has shown that graphene, a two-dimensional sheet of carbon, has a universal value of light absorption. Javey, Yablonovitch and their colleagues have now found that a similar generalized law applies to all 2D semiconductors. This discovery was made possible by a unique process that Javey and his research group developed in which thin films of indium arsenide are transferred onto an optically transparent substrate, in this case calcium fluoride.
“This provided us with ultrathin membranes of indium arsenide, only a few unit cells in thickness, that absorb light on a substrate that absorbed no light,” Javey says. “We were then able to investigate the optical absorption properties of membranes that ranged in thickness from three to 19 nanometers as a function of band structure and thickness.”
Using the Fourier transform infrared spectroscopy (FTIR) capabilities of Beamline 1.4.3 at Berkeley Lab’s Advanced Light Source, a DOE national user facility, Javey, Yablonovitch and their co-authors measured the magnitude of light absorptance in the transition from one electronic band to the next at room temperature. They observed a discrete stepwise increase at each transition from indium arsenide membranes with an AQ value of approximately 1.7-percent per step.
“This absorption law appears to be universal for all 2D semiconductor systems,” says Yablonovitch. “Our results add to the basic understanding of electron–photon interactions under strong quantum confinement and provide a unique insight toward the use of 2D semiconductors for novel photonic and optoelectronic applications.”
Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more information, visit http://www.lbl.gov.
The DOE Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit science.energy.gov.
The Advanced Light Source is a third-generation synchrotron light source producing light in the x-ray region of the spectrum that is a billion times brighter than the sun. A DOE national user facility, the ALS attracts scientists from around the world and supports its users in doing outstanding science in a safe environment. The Advanced Light Source is a third-generation synchrotron light source producing light in the x-ray region of the spectrum that is a billion times brighter than the sun. A DOE national user facility, the ALS attracts scientists from around the world and supports its users in doing outstanding science in a safe environment. For more information, visit http://www.als.lbl.gov/.
SOURCE: The U.S. Department of Energy
The 2010 Deepwater Horizon may be forgotten to many, but remnants of its destruction still remain in the Gulf of Mexico. Mercifully, it appears that researchers at Texas A&M University “have developed a non-toxic sequestering agent–iron oxide nanoparticles coated in a polymer mesh that can hold up to 10 times their weight in crude oil.” In layman’s terms, they’ve engineered a material that can safely soak up oil.
As the story goes, the nanoparticles “consist of an iron oxide core surrounded by a shell of polymeric material,” with the goal being to soak up leftover oil that isn’t captured using conventional mechanical means. The next step? Creating an enhanced version that’s biodegradable; as it stands, the existing particles could pose a threat if not collected once they’ve accomplished their duties.
Well-defined, magnetic shell cross-linked knedel-like nanoparticles (MSCKs) with hydrodynamic diameters ca. 70 nm were constructed through the co-assembly of amphiphilic block copolymers of PAA20–b-PS280 and oleic acid-stabilized magnetic iron oxide nanoparticles using tetrahydrofuran, N,N-dimethylformamide, and water, ultimately transitioning to a fully aqueous system. These hybrid nanomaterials were designed for application as sequestering agents for hydrocarbons present in crude oil, based upon their combination of amphiphilic organic domains, for aqueous solution dispersibility and capture of hydrophobic guest molecules, with inorganic core particles for magnetic responsivity.
The employment of these MSCKs in a contaminated aqueous environment resulted in the successful removal of the hydrophobic contaminants at a ratio of 10 mg of oil per 1 mg of MSCK. Once loaded, the crude oil-sorbed nanoparticles were easily isolated via the introduction of an external magnetic field. The recovery and reusability of these MSCKs were also investigated.
These results suggest that deployment of hybrid nanocomposites, such as these, could aid in environmental remediation efforts, including at oil spill sites, in particular, following the bulk recovery phase.