Spinning Kilometers of Nanotube Yarns
15 March 2010, 15:10
Categories: nanotubes-wires-fullerenes nanofibers
Researchers at Tianjin University in PR China have fabricated a continuous yarn of carbon nanotubes (CNTs). The CNTs have a structure that consists of multiple layers, and the yarn was spun through chemical vapor deposition (CVD). The CVD spinning process relies on the assembly of CNTs in the gas flow, which are attracted to each other by van der Waals interactions. The assembly of the CNTs in the gas flow forms a continuous sock-like CNT, which can then be mechanically spun out into a CNT yarn.
“The core scientific finding is our discovery that carbon nanotubes can self assemble in the gas flow into multiple geometry of layered structures by controlling the reaction chemistry and synthesis conditions,” says Ya-Li Li. The novel technique makes it possible to fabricate CNT yarns and multiple functional yarns that can be spun over kilometers with controlled CNT structures at atomic levels and micro levels.
“Our carbon nanotube yarn can be made either dense or hollow or multiple layered structures to meet specific structural and functional applications” says Li.
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Foresight 2010 Conference Presentations Posted Online
15 March 2010, 14:46
Categories: other
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The Foresight Institute has announced that all videos from their January Foresight 2010 Conference have been posted online. In all, there are 17 videos, so in case you’d like some guidance in getting started, consider starting with the top three talks as rated by conference participants:
Adaptive and Self-Reflective Systems
Presenter: Hod Lipson
Revolutionizing Transportation with AI
Presenter: Brad Templeton
The Contributions of Robert Freitas to Molecular Nanotechnology
Presenter: Ralph Merkle
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Nafion Exhibits Shape Memory Properties
11 March 2010, 13:22
Categories: polymers smt-polymorphic-shape-shifters
Researchers at the GM Research and Development Center have uncovered shape memory properties in a commercially available polymer that’s widely used to make fuel-cell membranes. The polymer, Nafion, can take on four different shapes in response to temperature changes. “It’s arguably the most versatile smart polymer ever discovered,” says Tao Xie, a scientist at GM.
The researchers trained a Nafion sheet to become different shapes at different temperatures: 140 ºC, 107 ºC, and 68 ºC. The polymer’s properties indicate that it could take on more shapes; it can be programmed to morph at arbitrary temperatures within a broad range as long as these temperatures are well separated.
Programming the 0.08 mm thick polymer sheet involves heating it to a high temperature within the glass transition range, deforming and then cooling it to a lower temperature while maintaining the deforming force. The Nafion sample was annealed at 140 ºC for two hours. “After the [cooling] event, that shape is locked,” Xie says. Deforming the polymer and cooling it again will program additional shapes.
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Light Moves Nanothin Objects
11 March 2010, 13:01
Categories: optics--photonics NEMS--MEMS
Light can be thought of as a stream of particles that can exert a force on whatever they strike. The Sun doesn’t knock you off your feet because the force is very small, but at the nanoscale it can be significant. Thus, Cornell researchers were able to use a very tiny beam of light to move a silicon structure up to 12 nm. That’s enough to completely switch the optical properties of the structure from opaque to transparent, they reported.
The researchers created a structure consisting of two thin, flat silicon nitride rings that are about 30 µm in diameter, 3 µm wide and 190 nm thick. One is mounted 1 micron above the other, and both are connected to a pedestal by thin spokes. When light at a resonant frequency of the rings, in this case infrared light at 1533.5 nm, is fed into the rings, the force between the rings is enough to deform the rings by up to 12 nm. When light in both rings is in phase — the peaks and valleys of the wave match — the two rings are pulled together. When it is out of phase, they are repelled.
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Increasing Efficiency In Dye-Sensitized Tandem Solar Cells
11 March 2010, 12:42
Categories: energy smt-energy-photovoltaic
Scientists at Monash University in Australia, and the universities of Wollongong and Ulm in Germany, have produced tandem dye-sensitized solar cells with a three-fold increase in energy conversion efficiency compared with previously reported tandem dye-sensitized solar cells. The key was the discovery of a new, more efficient type of dye that made the operation of inverse dye-sensitized solar cells much more efficient.
When the team combined two types of dye-sensitized solar cell (one inverse and the other conventional) into a simple stack, they were able to produce for the first time a tandem solar cell that exceeded the efficiency of its individual components.
“The tandem approach — stacking many solar cells together — has been successfully used in conventional photovoltaic devices to maximize energy generation, but there have been obstacles in doing this with dye-sensitized cells because there has not been a method for creating an inverse system that would allow dye molecules to efficiently pass on positive charges to a semiconductor when illuminated with light,” Dr. Udo Bach said.
“Inverse dye-sensitized solar cells are the key to producing dye-sensitized tandem solar cells, but the challenge has been to find a way to make them perform more effectively. By creating a way of making inverse dye-sensitized solar cells operate very efficiently we have opened the way for dye-sensitized tandem solar cells to become a commercial reality,” Bach explains.
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Nanobubbles On Super Non-Stick Surfaces
4 March 2010, 16:00
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, 15:45
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.
Read More
Paper
Video One (.avi)
Video Two (.avi)
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Nanooze At Epcot
3 March 2010, 14:38
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, 14:31
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, 14:02
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, 14:00
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, 13:38
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, 12:31
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, 12:07
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, 11:56
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, 11:30
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, 11:03
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, 10:50
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, 10:43
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, 14:30
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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