Biomimicry Evolves
2 September 2010, 17:38
Categories: biomimicry
.
There has been a flurry of activity recently in creating biomimetic materials and devices, enabled by nanostructured and microstructured materials. One approach, known as bioreplication, involves directly copying the organism, or its component of interest, by making molds that transfer important properties to cast materials.
Penn State scientists recently reported that they have developed a bioreplication method to create molds that retain nanoscale features. They chose blowfly eyes because they have potential application in the manufacture of solar cells. Blowflies have compound eyes that are roughly hemispherical; but within that half sphere, the surface is covered by macroscale hexagonal eyes with nanoscale features that collect more sunlight.
Additionally, scientists from Stanford University, Lewis & Clark College, the University of California-Berkeley, the University of Pennsylvania, Carnegie Mellon University, and Boston Dynamics have used a directional adhesive that mimics the setae and spatulae of a gecko’s toe, to enable a robotic climber to scale surfaces. They report that the adhesive only sticks when you pull in one direction, which is important for climbing because it requires little effort to attach and detach a robot’s foot.
“It’s very different from Scotch tape or duct tape, where, if you press it on, you then have to peel it off. You can lightly brush a directional adhesive against the surface and then pull in a certain direction, and it sticks itself. But if you pull in a different direction, it comes right off without any effort,” says Mark Cutkosky. “The new Stickybot that we’re working on right now has rotating ankles, which is also what geckos have,” he said. “Next time you see a gecko upside down or walking down a wall head first, look carefully at the back feet, they’ll be turned around backward. They have to be; otherwise they’ll fall.”
Posted by: The Editors
Archived (Restricted Access)
Stretched Molecule Ends Up Shorter Than It Started
2 September 2010, 17:02
Categories: polymers
.
A Duke and Stanford chemistry team has found a polymer molecule that’s so springy it snaps back from stretching much smaller than it was before. The finding occurred while searching for a molecule that might be useful for “self-healing” materials; the team was looking for polymers that can trigger a chemical reaction when stretched, and enable a material to make its own repairs.
While looking at polymers that contained tiny ring-shaped molecules called gem-difluorocyclopropanes (gDFC), it was discovered that some of these molecules emerged from stretching noticeably shorter than when they went in. But not only were the gDFCs snapping back smaller than they started, it also appeared that before snapping back they were actually trapped in an unusual stretched state far longer than normal, a reactive state called a 1,3-diradical.
Posted by: The Editors
Archived (Restricted Access)
Emerging Nanoarchitects
31 August 2010, 15:23
Categories: designers nanotubes-wires-fullerenes
The current issue of NANO magazine (issue no. 19) looks at nanotechnology being applied to objects in our everyday lives, and its promise for the future. The issue posits that nanotechnology has great potential for architecture and construction, as buildings are a major contributor to global warming.
Nanotechnology in architecture is principally addressed by Sylvia Leydecker in the issue. She states that innovation-driven materials and products are critical in achieving green construction, which is now at the forefront of much architectural debate. Leydecker believes that nanomaterials have a huge potential in this area, which is yet to be realized, as architects have not yet engaged fully with what is available. As a basic principle, she call for architects, planners and project developers to learn and understand the possibilities offered by nanotech, if they are to meaningfully address sustainability in their work.
Following on from that plea that architects become more acquainted with nanotechnology, the magazine identifies Decker Yeadon in New York City as a practice that has come up with new concepts based on nanotechnology, which could shape the future of homes and offices. As reported on this website, Decker Yeadon has invested in making Buckypaper, a material which can be electrically-conductive, and consists of single-walled nanotubes. As half of all energy consumption and greenhouse gas emissions in the U.S. can be attributed to buildings, it is hoped that this new materials like this might lead to applications to reduce cooling-costs and greenhouse gas emissions in hot climates. Other nano-based ideas for sustainable buildings are discussed in the magazine, including low power smart devices that would help control ambient temperatures.
Posted by: The Editors
Archived (Restricted Access)
Nanostructures Quickly Sterilize Water
31 August 2010, 14:55
Categories: filtration nanotubes-wires-fullerenes
Researchers at Stanford University have demonstrated a new strategy for sterilizing water by killing bacteria with silver nanowires and carbon nanotubes. The approach takes advantage of the nanostructures’ unique abilities to form electrically-conducting, high surface area coatings on cotton.
“Our chief insight over previous work is that using silver nanowires, instead of nanoparticles, allows the silver to be placed at an electrical voltage,” explains Yi Cui of Stanford University. “As it turns out, this dramatically improves the antibacterial effect of the silver, allowing for the high speed operation necessary to enable the water sterilization device.”
The group dyed regular cotton cloth with ink containing the two different nanomaterials, silver nanowires and carbon nanotubes (CNTs). “The backbone of our material, cotton, was chosen since it is cheap, widely available, and chemically and mechanically robust,” says Cui. “These considerations are extremely important for making filters of practical importance and are a challenge for many other technologies, including electrospun nanofibrous filters. The pores between fibers in cotton are in the range of tens to hundreds of micrometers, much larger than the length scale of bacteria, which prevents the device from mechanically clogging during use.” Hence, the new approach departs from existing filters, which remove bacteria from water with small pores that can ultimately clog and subsequently require replacement filters.
The team tested their filtration device and reported that a gravity fed device operating at 100000 L/(h m2) can inactivate >98% of bacteria with only several seconds of total incubation time.
Posted by: The Editors
Archived (Restricted Access)
Windows As Power Generators
31 August 2010, 13:51
Categories: nanoparticles smt-energy-photovoltaic
.
Norwegian company EnSol AS has patented a ground breaking, novel thin film solar cell technology which they seek to develop commercially by 2016. The company is working with experts in the University of Leicester to develop the revolutionary new type of solar cell material that could be coated as a thin film on, for example, windows in buildings to produce power on a large scale.
“The material has been designed by EnSol AS and is based on nanoparticles that can be synthesised in Leicester,” says Professor Chris Binns. “In fact, following some initial investment by the company, the equipment we have here at the University of Leicester is uniquely suited in the world to produce small amounts of the material for prototypes.”
“The work is important since the solar cells are based on a new operating principle and different to Si solar cells,” Binns continutes. “One of the key advantages is that it is a transparent thin film that can be coated onto window glass so that windows in buildings can also become power generators. Obviously some light has to be absorbed in order to generate power but the windows would just have a slight tinting (though a transmission of only 8-10% is common place for windows in the ‘sun belt’ areas of the world). Conversely the structural material of the building can also be coated with a higher degree of absorption. This could be side panels of the building itself, or even in the form of ‘clip-together’ solar roof tiles. Also since it is a thin film that can be coated onto large areas it could become very much cheaper than conventional devices.”
The material is composed of metal nanoparticles (diameters ~10nm) embedded in a transparent composite matrix. The researcher are looking to achieve a cell efficiency of 20% or greater, which would be extraordinary.
Posted by: The Editors
Archived (Restricted Access)
Open Source Aerogel
29 August 2010, 18:21
Categories: gels--foams
Aerogel is not like conventional foams; it is a special porous material with extreme microporosity. Aerogel is composed of individual features, only a few nanometers in size, linked in a highly porous dendritic-like structure. The exotic substance has many unusual properties, such as low thermal conductivity, refractive index and sound speed – in addition to its exceptional ability to capture fast moving dust, as demonstrated by NASA.
Much of the research and development of aerogels has been performed by NASA and academic insitutions, but now, Aerogel.org is a new website that has been launched as an open source nanotech initiative. The mission of the site is to empower, inspire, and motivate people to pursue nanotechnology using open source methodology and to catalyze the discovery of new technological possibilities for aerogel materials in the process. It is based on the principle that making straightforward information about exciting science available to everyone is the best way to stimulate people to pursue science, engineering, and other creative endeavors.
Posted by: The Editors
Archived (Restricted Access)
Visible UV Light Protects Birds
29 August 2010, 18:20
Categories: coatings optics--photonics
Hundreds of millions of birds are killed every year due to collisions with glass surfaces. It is the reflective and transparent characteristics of glass that make windows and facades invisible killers . Birds see the tree or sky reflected in a window or the nature behind the glazing, but not the glass itself; it is not recognized as a barrier. To prevent these collisions, the glass must be made visible to birds.
Knowing that birds possess the ability to see light in the ultraviolet spectrum, ARNOLD GLAS has developed ORNILUX Bird Protection Glass. The glass has a patterned UV reflective coating making it visible to birds (top image, right) while maintaining transparency to the human eye (top image, left). It has been tested by Max-Planck-Institute. During these experiments, various glass types were tested on over 850 birds from 19 different species, resulting in up to 75% bird strike reduction in comparison to standard double glazing.
The coating was patented back in 2006 by Dr. Alfred Meyerhuber (EP1319335), and the patent claims include information on how the coating reflects wavelengths in the UV range of 100nm – 380nm.
Posted by: The Editors
Archived (Restricted Access)
Paint Kills Bacteria On Contact
26 August 2010, 15:06
Categories: bionanotech--nanobiotech coatings
Building on an enzyme found in nature, researchers at Rensselaer Polytechnic Institute have created a nanoscale coating for surgical equipment, hospital walls, and other surfaces which safely eradicates methicillin resistant Staphylococcus aureus (MRSA), the bacteria responsible for antibiotic resistant infections.
“We’re building on nature,” said Jonathan S. Dordick. “Here we have a system where the surface contains an enzyme that is safe to handle, doesn’t appear to lead to resistance, doesn’t leach into the environment, and doesn’t clog up with cell debris. The MRSA bacteria come in contact with the surface, and they’re killed.”
In tests, 100 percent of MRSA in solution were killed within 20 minutes of contact with a surface painted with latex paint laced with the coating.
The new coating marries carbon nanotubes with lysostaphin, a naturally occurring enzyme used by non-pathogenic strains of Staph bacteria to defend against Staphylococcus aureus, including MRSA. The resulting nanotube-enzyme “conjugate” can be mixed with any number of surface finishes — in tests, it was mixed with ordinary latex house paint.
Posted by: The Editors
Archived (Restricted Access)
Hygroelectric Power: Electricity From Humid Air
26 August 2010, 14:56
Categories: energy
Imagine devices that capture electricity from the air ― much like solar cells capture sunlight ― and using them to light a house or recharge an electric car. Imagine using similar panels on the rooftops of buildings to prevent lightning before it forms. Strange as it may sound, scientists already are in the early stages of developing such devices, according to a report presented yesterday at the 240th National Meeting of the American Chemical Society (ACS).
“Our research could pave the way for turning electricity from the atmosphere into an alternative energy source for the future,” said study leader Fernando Galembeck, Ph.D. His research may help explain a 200-year-old scientific riddle about how electricity is produced and discharged in the atmosphere. “Just as solar energy could free some households from paying electric bills, this promising new energy source could have a similar effect,” he maintained.
The notion of harnessing the power of electricity formed naturally has tantalized scientists for centuries. They noticed that sparks of static electricity formed as steam escaped from boilers. Workers who touched the steam even got painful electrical shocks. Famed inventor Nikola Tesla, for example, was among those who dreamed of capturing and using electricity from the air. It’s the electricity formed, for instance, when water vapor collects on microscopic particles of dust and other material in the air. But until now, scientists lacked adequate knowledge about the processes involved in formation and release of electricity from water in the atmosphere, Galembeck said. He is with the University of Campinas, Brazil.
Scientists once believed that water droplets in the atmosphere were electrically neutral, and remained so even after coming into contact with the electrical charges on dust particles and droplets of other liquids. But new evidence suggested that water in the atmosphere really does pick up an electrical charge.
Galembeck and colleagues confirmed that idea, using laboratory experiments that simulated water’s contact with dust particles in the air. They used tiny particles of silica and aluminum phosphate, both common airborne substances, showing that silica became more negatively charged in the presence of high humidity and aluminum phosphate became more positively charged. High humidity means high levels of water vapor in the air ― the vapor that condenses and becomes visible as “fog” on windows of air-conditioned cars and buildings on steamy summer days.
“This was clear evidence that water in the atmosphere can accumulate electrical charges and transfer them to other materials it comes into contact with,” Galembeck explained. “We are calling this ‘hygroelectricity’, meaning ‘humidity electricity’.”
In the future, he added, it may be possible to develop collectors, similar to the solar cells that collect the sun to produce electricity, to capture hygroelectricity and route it to homes and businesses. Just as solar cells work best in sunny areas of the world, hygroelectrical panels would work more efficiently in areas with high humidity, such as the northeastern and southeastern United States and the humid tropics.
Posted by: The Editors
Archived (Restricted Access)
Seaswarm Cleans Oil Spills
26 August 2010, 14:38
Categories: filtration nanofibers
.
By autonomously navigating the water’s surface, Seaswarm is MIT’s new system for ocean-skimming and oil removal.
Seaswarm uses a photovoltaic powered conveyor belt made of a thin nanowire mesh to propel itself and collect oil. The nanomaterial, patented at MIT, can absorb up to 20 times its weight in oil. The flexible conveyor belt softly rolls over the ocean’s surface, absorbing oil while deflecting water because of its hydrophobic properties.
Seaswarm is intended to work as a fleet, or “swarm” of vehicles, which communicate their location through GPS and WiFi in order to create an organized system for collection that can work continuously without human support. Because they are smaller than commercial skimmers attached to large fishing vessels, they are able to navigate hard to reach places like estuaries and coast lines.
Seaswarm works by detecting the edge of a spill and moving inward until it has removed the oil from a single site before joining other vehicles that are still cleaning. Oil is “digested” locally so that Seaswarm does not need to make repeated trips back to shore, which would dramatically slow collection time.
The fleet uses cutting edge nanotechnology to solve current environmental problems while envisioning long-term solutions for the future. With a new design strategy we can revive and preserve the quality of our oceans.
Posted by: The Editors
Archived (Restricted Access)
Spinning Revolution Fibres
25 August 2010, 14:47
Categories: nanofibers filtration
An New Zealand nanotechnology start-up, Revolution Fibres, is building a machine that can electro-spin extremely fine nanofibers for clothing, filtration, reinforcing, electronics and packaging. The fibers are extremely strong due to the molecular alignment of the polymer particles.
Their first product will be biodegradable air filtration mats, created by diffusing the nanofibers onto a plate made from reformed potato starch. “It is a good use of something that would normally be chucked away,” says technical director Iain Hosie. “What is good about biomaterials is it means you stay away from plastic and petrochemical-derived products.” Hosie says the world is on the cusp of a boom in electro-spinning, a technology that’s 150 years old. “There’s been a lot of research, not a lot of commercialization.”
Air filtration mats of nanofibers provide a much greater surface area to capture pathogens and dust particles, while having less impact on airflow than other mat-fibre types. As well as conventional mechanical trapping technology of existing air filters, the new mats utilize the enhanced entrapment properties from van der Waals forces due to the fibers being so small.
Revolution Fibres are also going one step further. Instead of providing microbial protection by incorporating silver nanoparticles, they’re using manuka and other plant-based extracts to neutralize pathogens.
Posted by: The Editors
Archived (Restricted Access)
Pavement Coating Cleans Air
25 August 2010, 14:40
Categories: nanoparticles
A product developed by F. C. Nüdling reduces the amount of nitrogen oxide in air by coating paving slabs with titanium dioxide nanoparticles. Titanium dioxide is a photocatalyst that can convert harmful substances such as nitrogen oxides into nitrates. It uses sunlight to accelerate a naturally-occurring chemical reaction, the speed of which changes with exposure to light.
“Experiments in Italian cities had already shown that photocatalytic paving slabs can improve the air quality,” says Dr. Herrchen. “We wanted to see if they would also be effective here in Germany, where we have lower levels of light intensity and fewer hours of sunshine. Of course, the more intense the sunshine, the quicker the degradation of harmful substances, so our aim was to identify the formula with the highest photocatalytic efficiency rating.”
During an extended time field test, nitrogen oxide degradation rates of 20 to 30 percent were recorded in specially-created street canyons. The measurements were taken at a height of three meters above the photocatalytic slabs, in variable wind and light conditions. When the wind was still, the experts recorded degradation rates as high as 70 percent for both nitrogen monoxide (NO) and nitrogen dioxide (NO2). Measurements likewise taken at a height of three meters above the Gothaer Platz in Erfurt, Germany, which is already paved with Air Clean paving slabs, revealed an average degradation rate of 20 percent for NO2 and 38 percent for NO.
Posted by: The Editors
Archived (Restricted Access)
Land Art Generator
11 August 2010, 17:03
Categories: designers smt-energy-photovoltaic
The UAE may be built on profits reaped from its oil-rich sands, but out of the region’s vast deserts rises a new vision for a solar farm unlike any we have seen before. Conceived by Decker Yeadon for the Land Art Generator competition, the Light Sanctuary is an elegantly unfurling ribbon of solar thin-film panels designed to take advantage of Dubai’s immense solar resources. The 40 km long stretch of ribbons consists of thin-film dye-sensitized solar cells that curl and undulate across the desert landscape, mimicking a mirage from afar and creating an immersive and sensual experience up close.
The unique vertical orientation of the solar ribbons capitalizes on the ability of the semi-translucent thin film panels to produce useful energy at a steep angle of solar exposure. This allows for energy production over a longer period throughout the day, and the panels also get a boost from reflected light off the high-albedo landscape. The solar cells also can tolerate direct sunlight (unlike silicone solar panels) and perform much better in the high-temperature conditions. Calibrated optimally, the project would generate 4592 megawatt hours (16530 gigajoules) of energy annually.
Posted by: The Editors
Archived (Restricted Access)
Plastic Sticker Improves Solar Cell Efficiency
11 August 2010, 09:59
Categories: energy smt-energy-photovoltaic
Genie Lens Technologies has developed a transparent Soloptics sticker that could increase the power output of solar panels by 10 percent. The polymer film is embossed with microstructures that bend incoming sunlight, causing the active materials in the panels to absorb more light, and convert more of it into electricity. Additionally, the film reduces light reflection off the surface of the panels, trapping the light. The technology is cheap and could lower the cost per watt of solar power. Also, unlike other technologies developed to improve solar panel performance, this one can be added to panels that have already been installed.
Posted by: The Editors
Archived (Restricted Access)
Nanotubes Might Take Flight
6 August 2010, 14:20
Categories: nanotubes-wires-fullerenes nanocomposites
In July, Solar Impulse triumphantly completed its first night flight. The ultralight aircraft was airborne for a total of 26 hours before finally landing as planned in Switzerland. It is now officially the first manned aircraft capable of flying day and night without fuel, powered entirely by solar energy.
Bayer is now working on the development of ultra-lightweight materials for the next version of the solar-powered aircraft. Baytubes® carbon nanotubes, from Bayer MaterialScience, might improve the strength of structural components while keeping their weight to a minimum. In 2013, a second prototype is scheduled to fly right round the world in five stages, each lasting five days, traveling at an average speed of 70 km/h.
Posted by: The Editors
Archived (Restricted Access)
Roller Painted Solar Cells
6 August 2010, 13:06
Categories: energy smt-energy-photovoltaic
A team at Seoul National University have come up with a highly efficient polymer solar cell fabrication method that is similar to painting with a roller. The researchers demonstrated the fabrication of a 40 nanometer thin polymer composite that was roller-painted on a 4cm x 8cm sheet of PET film.
“The roller painting process is easy-to-use, high throughput and the most widely used method for conventional painting” they report. “The substrate size for the roller painting is limitless, and the process cost is also low since it is a continuous process. A particular advantage of roller painting compared to other coating processes is ease of control of the film thickness and uniformity. Therefore, roller painting is a very promising process industrial use in thin film fabrication and organic electronics.”
The team found that the roller-painted polymer solar cells can achieve an efficiency of 4.5%. This is 20% higher than the optimum power conversion efficiency (PCE) of 3.9% for spin-coated solar cells. Even without annealing, the roller-painted solar cells achieved a PCE of 3.8%.
Posted by: The Editors
Archived (Restricted Access)
Nanotechnology For Water Purification
5 August 2010, 14:44
Categories: filtration safety--security
Nanotechnology refers to a broad range of tools, techniques and applications that simply involve particles on the approximate size scale of a few to hundreds of nanometers in diameter. Particles of this size have some unique physicochemical and surface properties that lend themselves to novel uses. Indeed, advocates of nanotechnology suggest that this area of research could contribute to solutions for some of the major problems we face on the global scale such as ensuring a supply of safe drinking water for a growing population, as well as addressing issues in medicine, energy, and agriculture.
Writing in the International Journal of Nuclear Desalination, researchers at the D.J. Sanghvi College of Engineering, in Mumbai, India, explain that there are several nanotechnology approaches to water purification currently being investigated and some already in use. “Water treatment devices that incorporate nanoscale materials are already available, and human development needs for clean water are pressing,” Alpana Mahapatra and colleagues Farida Valli and Karishma Tijoriwala, explain.
Water purification using nanotechnology exploits nanoscopic materials such as carbon nanotubes and alumina fibers for nanofiltration, it also utilizes the existence of nanoscopic pores in zeolite filtration membranes, as well as nanocatalysts and magnetic nanoparticles. Nanosensors, such as those based on titanium oxide nanowires or palladium nanoparticles are used for analytical detection of contaminants in water samples.
The impurities that nanotechnology can tackle depend on the stage of purification of water to which the technique is applied, the team adds. It can be used for removal of sediments, chemical effluents, charged particles, bacteria and other pathogens. They explain that toxic trace elements such as arsenic, and viscous liquid impurities such as oil can also be removed using nanotechnology.
“The main advantages of using nanofilters, as opposed to conventional systems, are that less pressure is required to pass water across the filter, they are more efficient, and they have incredibly large surface areas and can be more easily cleaned by back-flushing compared with conventional methods,” the team says.
For instance, carbon nanotube membranes can remove almost all kinds of water contaminants including turbidity, oil, bacteria, viruses and organic contaminants. Although their pores are significantly smaller carbon nanotubes have shown to have an equal or a faster flow rate as compared to larger pores, possibly because of the smooth interior of the nanotubes. Nanofibrous alumina filters and other nanofiber materials also remove negatively charged contaminants such as viruses, bacteria, and organic and inorganic colloids at a faster rate than conventional filters.
“While the current generation of nanofilters may be relatively simple, it is believed that future generations of nanotechnology-based water treatment devices will capitalize on the properties of new nanoscale materials,” the team says.
The researchers point out that several fundamental aspects of nanotechnology have raised concerns among the public and activist groups. They concede that the risks associated with nanomaterials may not be the same as the risks associated with the bulk versions of the same materials because the much greater surface area to volume ratio of nanoparticles can make them more reactive than bulk materials and lead to so far unrecognized and untested interactions with biological surfaces. Water purification based on nanotechnology has not yet led to any human health or environmental problems but the team echoes the sentiment of others that further research into the biological interactions of nanoparticles should be carried out.
Posted by: The Editors
Archived (Restricted Access)
Iranian City Utilizes Nanotech Traffic Paint
5 August 2010, 12:28
Categories: coatings nanocomposites
The urban passages and public spaces of Naqadeh, Iran, have been marked with nano traffic paints. The Lotus Nanopaint was supplied by Asia Technology Pioneers, an Iranian company.
According to the announcement, nanoparticles make the paint more durable against erosion and scratches compared to conventional cold traffic paints. Moreover, the new paint can compete with their conventional counterparts in terms of the price and quality and so far they have gained approval from municipalities and domestic contractors. According to the Asia Technology Pioneers, the paints last 1.5 times longer than ordinary paints.
Posted by: The Editors
Archived (Restricted Access)
Piezo Website Launched
5 August 2010, 11:42
Categories: smt-energy-piezoelectric
PI Ceramic, a leading manufacturer of piezo ceramic materials, piezo components and custom engineered piezo products, has released a new website. The site provides more technical background information on general piezo technology, application notes, tips & tricks, and several tutorials on piezo actuators, piezo materials and piezo composite transducers. Contents is currently available in the following three languages.
Posted by: The Editors
Archived (Restricted Access)
Largest Solar Nanotech Facility On The Horizon
5 August 2010, 10:20
Categories: smt-energy-photovoltaic
San Jose-based Solexant has announced that they plan to build a new solar film manufacturing plant in Oregon. The plant in Gresham will be the largest solar nanotechnology facility of its kind in the world.
Posted by: The Editors
Archived (Restricted Access)