Nanobubbles On Super Non-Stick Surfaces
4 March 2010, 17:00
Categories: superhydrophobicphilic self-cleaning
Scientists at the U.S. Department of Energy’s Brookhaven National Laboratory have obtained the first glimpse of minuscule air bubbles that keep water from wetting a super non-stick surface. “Our results explain how these nanocavities trap tiny bubbles which render the surface extremely water repellent,” said Brookhaven physicist Antonio Checco.
The research could lead to a new class of non-stick materials for a range of applications, including improved-efficiency power plants, speedier boats, and surfaces that are resistant to contamination by germs. Non-stick surfaces are important to many areas of technology, from drag reduction to anti-icing agents. These surfaces are usually created by applying coatings, such as Teflon, to smooth surfaces. But recently — taking the lead from observations in nature, notably the lotus leaf and some varieties of insects — scientists have realized that a bit of texture can help.
By incorporating topographical features on surfaces, they’ve created extremely water repellent materials. “We call this effect superhydrophobicity,” said Brookhaven physicist Benjamin Ocko. “It occurs when air bubbles remain trapped in the textured surfaces, thereby drastically reducing the area of liquid in contact with the solid.” This forces the water to ball up into pearl shaped drops, which are weakly connected to the surface and can readily roll off, even with the slightest incline.
“To get the first glimpse of nanobubbles on a superhydrophobic surface we created a regular array of more than a trillion nanocavities on an otherwise flat surface, and then coated it with a wax-like surfactant,” said Brookhaven’s Charles Black. This coated, nanoscale textured surface was much more water repellent than the flat surface alone, suggesting the existence of nanobubbles.
To prove that these ultra-small bubbles were present, the team carried out x-ray measurements at the National Synchrotron Light Source. “By watching how the x-rays diffracted, or bounced off the surface, we are able to image extremely small features and show that the cavities were mostly filled with air,” said Elaine DiMasi, a physicist at Brookhaven.
According to the scientists’ observations, the bubbles are only about 10 nm in size. The team’s results also show that these tiny bubbles have nearly flat tops. This is in contrast to larger, microbubbles, which have a more rounded top.
“This flattened configuration is appealing for a range of applications because it is expected to increase hydrodynamic slippage past the nanotextured surface,” Checco said. “Moreover, the fact that water hardly penetrates into the nanotextures, even if an external pressure is applied to the liquid, implies that these nanobubbles are very stable.”
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Biomimetic Hairy Surfaces Repel Water
4 March 2010, 16:45
Categories: biomimicry superhydrophobicphilic
University of Florida researchers have crafted a flat surface that refuses to get wet. Instead, water droplets skitter across it like ball bearings tossed on ice. The nearly perfect hydrophobic surface consists of small bits of flat plastic in the shape and pattern of minute spider hairs.
Spiders use their water-repelling hairs to stay dry or avoid drowning, with water spiders capturing air bubbles and toting them underwater to breathe. “They have short hairs and longer hairs, and they vary a lot. And that is what we mimic,” said Wolfgang Sigmund, a professor of materials science and engineering whom is also known for his work with carbon nanotubes.
The surface works equally well with hot or cold water. When water scampers off the surface, it picks up and carries dirt with it, in effect making the surface self-cleaning. As such, it is ideal for some food packaging, or windows, or solar cells that must stay clean to gather sunlight. Boat designers might coat hulls with it, making boats faster and more efficient.
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Nanooze At Epcot
3 March 2010, 15:38
Categories: other
A new long-term exhibition at the Walt Disney World Resort in Lake Buena Vista, FL, will bring visitors face to face with the nanoworld. Housed at INNOVENTIONS at Epcot, the exhibition Take a Nanooze Break features a series of interactive, continually updated displays that allow visitors to manipulate models of molecules, study everyday items at the nanoscale, and interact with scientists and engineers who conduct the latest nano research.
“The experience is immersive and gives guests a number of ways to view a world that is too small to see,” says Carl Batt of Cornell University, the lead researcher for the project. “It also gives guests a view of nanotechnology from real scientists.”
Based upon the National Science Foundation (NSF)-supported children’s magazine and website Nanooze, the exhibition was developed with further NSF support by collaborators from Cornell University and Tamarack Design of Ithaca, NY.
This thing was designed?
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Woven Fabric Heaters
3 March 2010, 15:31
Categories: nanotubes-wires-fullerenes
Thanks to the combination of two new dispersion technologies aqueous suspensions of Baytubes® carbon nanotubes (CNTs) can be produced which contain single tubes and thus show a high electrical and thermal conductivity. Multifilament yarns coated with such CNT dispersions can be woven to efficient fabric heaters. Such heaters already performed well in preventing the water in water storage tanks of JR Hokkaido’s Ryuhyo-Norokko train from freezing.
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MIT Media Lab Commissions eSkin From Peratech
3 March 2010, 15:02
Categories: designers sensors
A leader in new materials for tactile technologies, Peratech Limited, has announced that they have been commissioned by the MIT Media Lab to develop a new type of electronic skin that enables robotic devices to detect not only that they have been touched but also where and how hard the touch was.
The key to the sensing technology is Peratech’s patented QTC (Quantum Tunnelling Composites) materials. QTCs are a unique new material type which provides a measured response to pressure (force and/or touch) by changing its electrical resistance, much as a dimmer light switch controls a light bulb. This enables a simple electronic circuit within the robot to determine touch.
Uniquely, QTCs provide a proportional response, detecting ‘how hard’ they have been touched. Further, using Peratech’s patented XY scanning technology, the robot is able to detect where on a matrix of sensors applied to areas such as the forearms, shoulders and torso, it has been touched.
QTCs are electro-active polymeric materials made from metallic or non-metallic filler particles combined in an elastomeric binder. These enable the action of ‘touch’ to be translated into an electrical reaction, enabling a vast array of devices to incorporate very thin and highly robust ‘sensing’ of touch and pressure. QTCs unique properties enable it to be made into force sensitive switches of any shape or size. QTC switches and switch matrices can be screen printed allowing for development and integration of switches that are as thin as 75 microns.
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Stretchable, Porous, Conductive Energy Textiles
3 March 2010, 15:00
Categories: nanotubes-wires-fullerenes energy
Stanford engineer Yi Cui and his team have manufactured new energy storage devices out of paper and cloth, with a range of potential applications. By dipping ordinary paper or fabric in a special ink infused with single walled nanotubes, Cui has found a way to cheaply and efficiently manufacture lightweight paper batteries and supercapacitors (which store energy by electrostatic rather than chemical means), as well as stretchable, conductive eTextiles that are capable of storing energy while retaining the mechanical properties of ordinary paper or fabric.
While the technology is still new, the Stanford researchers have envisioned numerous functional uses for their inventions. Homes of the future could one day be lined with energy-storing wallpaper. Gadget lovers would be able to charge their portable appliances on the go, simply plugging them into a receptacle woven into their T-shirts. Energy textiles might also be used to create moving-display apparel, reactive high-performance sportswear and wearable power for a soldier’s battle gear.
“This is the right time to really see what we learn from nanoscience and do practical applications that are extremely promising,” said Cui. “The beauty of this is, it combines the lowest cost technology that you can find to the highest tech nanotechnology to produce something great. I think this is a very exciting idea … a huge impact for society.”
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S.NET 2010 Conference Call
3 March 2010, 14:38
Categories: other
The Society for the Study of Nanoscience and Emerging Technologies (S.NET) is an international association that promotes open intellectual exchange towards the advancement of knowledge and understanding of nanotechnologies in society. The Society represents diverse communities, viewpoints, and methodologies in the social sciences and humanities. It welcomes contributions from scientists and engineers that advance the critical reflection of nanotechnologies and related developments.
The S.NET conference program committee for the Second Annual Conference of the Society for the Study of Nanoscience and Emerging Technologies invites all discussions of anthropological, cultural, economic, ethical, historical, philosophical, political, literary, artistic, and sociological aspects of nanosciences and emerging technologies. This can take the form of individual abstracts, proposals for sessions with three to five presentations, and other formats. 250-word abstracts for individual papers, up to 1000-word-abstracts for sessions and other formats can be submitted online until March 15. Notifications of acceptance will be mailed by April 30, 2010. Graduate students are encouraged to submit.
The list of this year’s plenary speakers includes Armin Grunwald, Richard Jones, Andrew Light, Bernard Stiegler, and Jan Youtie. If you would like to contribute to S.NET 2010, download the Call for Papers. Then, to make a submission, go to EasyChair. There is no need to submit entire papers. When the system asks you to upload your paper, please upload a PDF or DOC version of your abstract – not docx, txt, or other file types. It is sufficient to enter the first paragraph of your submission into the space provided for abstracts.
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Interested In A Career In Nano?
3 March 2010, 13:31
Categories: scientists
In a recent posting on Nanowerk, renowned nanopioneer Eric Drexler attempts to answer the question on how students should prepare for a career in nanotechnology. His advice centers on fundamentals, outlining areas of knowledge are are universally important, and offering suggestions for how to approach both specialized choices and learning in general.
Drexler also offers observations about the future of nanotechnology, the context for future careers. However, as you might imagine, providing a good answer is challenging. The term ‘Nanotechnology’ refers to a notoriously broad range of areas of science and technology, and progress during a student’s career will open new areas, and some are yet to be imagined. Choices within this complex and changing field should reflect a student’s areas of interest and ability, current background, level of ambition, and willingness to to accept risk – there is a trade-off between pioneering new directions and seeking a secure career path.
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An Invisible Water Valve
3 March 2010, 13:07
Categories: coatings superhydrophobicphilic
Researchers from the Kawamura Institute of Chemical Research, Japan, are using a nanotextured thin film to control the passage of water through a glass tube. The team created a hydrophilic–superhydrophobic boundary in a 6 mm diameter tube. The top half of the inner surface is hydrophilic and the bottom half is covered with a superhydrophobic nanotextured film.
Water dropped into the top of a vertically held glass tube collects spontaneously and is stopped at the boundary, forming a water column as if there was an invisible stop valve built inside the device. When more water is added, the stopped water column falls down suddenly due to the effect of gravity.
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Light Spins Nanofibers
3 March 2010, 12:56
Categories: nanofibers
Researchers at the University of Salento, Italy, have succeeded in rotating polymer nanofibers using just light. The new nanorotors might be used to make nanomachines based on photonic circuits, as well as help to develop next-generation photonic force microscopes. While previous methods to rotate elongated objects, such as nanowires or nanotubes, required a rotating polarized beam of light, the new technique does not need to manipulate the beam’s polarization or its intensity.
The researchers begin by trapping a polymeric nanofiber at one end using low laser power and then move it to a point slightly higher than its height. The nanofiber aligns itself along the light beam axis and a circular cross-section image can be observed on a CCD camera. Next, the researchers increase the optical trap stiffness, by increasing the laser output power. When they then increase the stage height, the fiber starts to tilt and rotates. The rotation can thus be controlled by either increasing the power of the laser, or further increasing the nanofiber’s tilt.
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Metal-Free Nanotubes Made In Space
3 March 2010, 12:30
Categories: nanotubes-wires-fullerenes techniques
Space apparently has its own recipe for making carbon nanotubes, and metals are conspicuously missing from the list of ingredients. “Instead, nanotubes were produced when graphite dust particles were exposed to a mixture of carbon monoxide and hydrogen gases,” explains NASA scientist Joseph Nuth.
The structure of the carbon nanotubes produced by Nuth’s experiments was determined by Yuki Kimura, a materials scientist at Tohoku University, Japan, who examined the samples under a powerful transmission electron microscope. He saw particles on which the original smooth graphite gradually morphed into an unstructured region and finally to an area rich in tangled hair-like masses. A closer look with an even more powerful microscope showed that these tendrils were in fact cup-stacked carbon nanotubes, which resemble a stack of Styrofoam cups with the bottoms cut out.
These observations surprised Kimura because carbon nanotubes are typically grown with platinum or another metal as a catalyst, yet Nuth’s reaction had used no metals. Kimura checked for contamination but “did not find the presence of metallic particles accompanying the nanotube in the sample,” he says.
“I am amazed at the implications, not only for astrophysics but also for materials science,” says Dick Zare, the chair of the chemistry department at Stanford University. “Could Nature know a new chemistry for making carbon nanotubes that we have yet to discover?”
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Efficient Lighting From Nanofiber-Based Technology
3 March 2010, 12:03
Categories: nanofibers smt-luminescent-light-emit
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RTI International has developed a revolutionary lighting technology that is more energy efficient than the common incandescent light bulb and does not contain mercury, making it environmentally safer than the compact fluorescent light bulb.
RTI’s technology centers around advancements in the nanoscale properties of materials to create high-performance, nanofiber-based reflectors and photoluminescent nanofibers (PLN). When the two nanoscale technologies are combined, a high-efficiency lighting device is produced that is capable of generating in excess of 55 lumens of light output per electrical watt consumed. This efficiency is more than five times greater than that of traditional incandescent bulbs.
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Commercialized Conductive Ink Incorporates Graphene
3 March 2010, 11:50
Categories: coatings nanotubes-wires-fullerenes
This conductive ink by Vorbeck Materials is one of the first products on the market to incorporate graphene, a sheet of carbon just one atom thick. Applying the ink with standard techniques can print wiring for RFID antennas, keypads, and display backplanes directly onto paper or cardboard stock. Unlike metallic conductive inks, the graphene ink does not have to be heated after printing.
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Nanotheatrics
3 March 2010, 11:43
Categories: artists
QuestFest 2010, an international visual theatre festival, will return to the Baltimore/Washington area March 1-14, 2010, with a two-week long festival of performances and workshops in venues and schools throughout the area.
The show Nano will experiment with the issues and images of Nanotechnology as they apply to deaf, hard of hearing and hearing people. How nanotechnology can manipulate matter on the molecular level and on the genetic level raises both hope and ethical questions for the future of humanity. Using gestures in action, masks, multimedia and dark comedy, the cast portrays five scientists who make the discovery that size matters.
Nano will be showing at the Theatre Malz on the Gallaudet University campus in Washington March 11-14.
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Architects Synthesize Carbon Nanotube Buckypaper
19 February 2010, 15:30
Categories: nanotubes-wires-fullerenes designers
Fullerenes come in a variety of shapes, but all of the molecules in the Fullerene family are composed entirely of carbon. They might be cylindrical Fullerenes, in which case they are called carbon nanotubes or buckytubes, or they might be more complex shapes. Fullerene molecules might also be spherical, as in the buckminsterfullerene C60 molecule, which was named in honor of R. Buckminster Fuller, architect of the geodesic dome.
Despite the homage, Buckminster Fuller never worked directly with nanotechnology. But to be fair, few architects have. Even today, as other disciplines rush to experiment with nanotechnology in the pursuit of new applications, it is extremely rare to find anyone in the architecture community that is engaged in nanotech research and development. Sure, a few nano-enabled building products have been specified for some projects here and there, but architects are well behind other creative disciplines, such as industrial design and apparel design.
That might be changing. Decker Yeadon, a young firm in New York City, has just synthesized a thin sheet of carbon nanotubes, called Buckypaper. To make it, they first dispersed single walled carbon nanotubes in sodium dodecyl sulfate and deionized water. Because the 1–2 nanometer diameter nanotubes are hydrophobic, Decker Yeadon used sodium dodecyl sulfate as a surfactant that enabled the nanotubes to disperse well in water.
The solution containing the nanotubes was then poured into a vacuum filtration unit, which contained a microporous filtration membrane with 200 nanometer diameter pores. Because each nanotube was just over 20 µm long, the tubes collected on the surface of the membrane as the solution was drawn through its pores, like long hairs collecting at the drain of a tub, leaving behind a “paper” mat that is less than 100 µm thick.
Although they are the first architects to make Buckypaper, there has been a great deal of interest in the scientific community, recently, surrounding Buckypaper research. Like the carbon nanotubes it is made of, Buckypaper has a number of novel properties that could be advantageous for a variety of applications. It is hundreds of times stronger than steel, it can filter particles, it can conduct and disperse heat like metals, and it can conduct electricity.
“We’ve been very active in pursuing new applications for smart materials and emergent nanomaterials,” says Martina Decker. “The Buckypaper material that we’ve just made springs from our earlier attempts, in 2009, to make an electrically conductive coating of multi-walled nanotubes. We’re hopeful that this new Buckypaper can be used as a thin, flexible electrode surface in an artificial muscle that we’re developing for architecture. We’re excited about its potential use in other applications as well.”
The first prototype of the artificial muscle should be completed and demonstrated this year. “Our first prototype will be small, because we’re somewhat limited by the size of Buckypaper we can currently produce,” explains Peter Yeadon. “The sheet is about the same size as the filtration membrane, 90 mm in diameter. Although its surface has an area that is similar to the palm of my hand, the active surface area of the nanotubes in the material is tremendous. If we were to take all of those tiny tubes and roll them out flat, they would have a surface area of about 100 square meters.”
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Nanomaterials for the Future
19 February 2010, 14:21
Categories: other
The current issue of NANO Magazine, titled “Nanomaterials for the Future,” focuses on the role nanomaterials will play in a clean tech future. The issue covers: how nano-enhanced products are beating the recession; nanotech’s contribution to clean tech; which nano innovations in food are here and whether we can really make next generation batteries ‘green’.
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Nanoparticle Solar Cells
19 February 2010, 13:46
Categories: nanoparticles smt-energy-photovoltaic
Broadband Solar, a startup out of Stanford University, is developing nanoparticle coatings that increase the amount of light that thin-film solar cells can absorb. The nanoparticles redirect light along the plane of the solar cell, so that each photon takes a longer path through the material, thus increasing its chances of dislodging an electron before it can reflect back out of the cell.
The nanoparticles also increase light absorption by creating strong local electric fields. The particles, which are essentially nanoscale antennas, are very similar to radio antennas. They’re much smaller because the wavelengths they interact with are much shorter than radio waves.
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Highly Absorbing, Flexible Solar Cells
19 February 2010, 13:07
Categories: energy smt-energy-photovoltaic
Using arrays of long, thin silicon wires embedded in a polymer substrate, a team of scientists from the California Institute of Technology (Caltech) has created a new type of flexible solar cell that enhances the absorption of sunlight and efficiently converts its photons into electrons. The solar cell does all this using only a fraction of the expensive semiconductor materials required by conventional solar cells.
“These solar cells have, for the first time, surpassed the conventional light-trapping limit for absorbing materials,” says Harry Atwater. The light-trapping limit of a material refers to how much sunlight it is able to absorb. The silicon-wire arrays absorb up to 96 percent of incident sunlight at a single wavelength and 85 percent of total collectible sunlight. “We’ve surpassed previous optical microstructures developed to trap light,” he says.
Although the wires are tiny, they are not at the scale of nanowires. Each silicon wire measures between 30 and 100 microns in length, and 1 micron in diameter. “The entire thickness of the array is the length of the wire,” notes Atwater. “But in terms of area or volume, just 2% of it is silicon, and 98% is polymer.”
In other words, while these arrays have the thickness of a conventional crystalline solar cell, their volume is equivalent to that of a 2 µm thick film. The composition and thinness of the cells means that they are also flexible. “Having these be complete flexible sheets of material ends up being important,” he says, “because flexible thin films can be manufactured in a roll-to-roll process, an inherently lower-cost process than one that involves brittle wafers, like those used to make conventional solar cells.”
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Trapping An Electron
17 February 2010, 16:43
Categories: quantum-mechanics
In the quest to design and construct a radically new kind of quantum computer, one major hurdle has been finding a way to manipulate the single electrons that very likely will constitute the computer’s processing components or “qubits.”
Researchers at Princeton University and the University of California at Santa Barbara have now been able to find out how to do just that, and have demonstrated a method that alters the properties of a lone electron without disturbing the trillions of electrons in its immediate surroundings.
The feat is essential to the development of future varieties of superfast computers with near-limitless capacities for data. The researchers trapped one or two electrons in two tiny corrals, known as quantum wells, on the surface of a high-purity, gallium arsenide chip. The depth of each well is controlled by varying the voltage on tiny electrodes or gates. Like a juggler tossing two balls between two hands, the researchers can move the electrons from one well to the other by selectively toggling the gate voltages. Electrons trapped in these corrals form “spin qubits,” quantum versions of classic computer information units known as bits.
“If you can take a small enough object like a single electron and isolate it well enough from external perturbations, then it will behave quantum mechanically for a long period of time,” said Jason Petta. “All we want is for the electron to just sit there and do what we tell it to do. But the outside world is sort of poking at it, and that process of the outside world poking at it causes it to lose its quantum mechanical nature.”
“Our approach is really to look at the building blocks of the system, to think deeply about what the limitations are and what we can do to overcome them,” Petta said. “But we are still at the level of just manipulating one or two quantum bits, and you really need hundreds to do something useful.”
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Ultrathin Glass
17 February 2010, 15:18
Categories: coatings self-cleaning
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If you walk around Ataturk’s Mausoleum in Ankara, you are walking on it. If you visit certain hospitals in the UK, you might be touching it. If you see an unusually clean train, you are probably looking at it. All of these surfaces have been coated with a thin layer of glass, called silicon dioxide ultrathin layering.
The flexible and breathable glass coating is approximately 100 nm thick, and so it is completely undetectable. It is food safe, enviro-friendly, and it can be applied to almost any surface within seconds . When coated, all surfaces become easy to clean and anti-microbial. Houses, cars, ovens, wedding dress or any other protected surface become stain resistant and can be easily cleaned with water; no cleaning chemicals are required.
“In essence, we extract molecules of SiO2 (the primary constituent of glass) from quartz sand, and then we add the molecules to water or ethanol,” explains Neil McClelland. “The really clever part is that there are no added nanoparticles, resins or additives — the coatings form and bond due to quantum forces. Our research informs us that in all probability, we offer the most versatile coating in the world. We are happy to hear about any other technology which offers the same range of applications. Very soon almost every product that you purchase will be protected with some form of easy-to-clean coating. It just so happens that we offer something that everyone finds fascinating . The concept of spray-on glass is just mind-boggling.”
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