Using carbon nanotubes, researchers in Japan have developed a new viscoelastic material that remains stable over a very wide temperature range, from –196 °C to 1000 °C. This is the first such material of its kind, as rubbery materials like these normally break down at high temperatures and become brittle when too cold. Viscoelastic materials behave like thick liquids (for example, honey) but are also reversibly elastic, like rubber bands. One example of such a material is polymer foam that is widely used in earplugs; they adapt themselves to the shape of your ear yet recover their original form after they are removed. The new rubber is made from a random network of interconnected single-, double- and triple-walled carbon nanotubes and has the same viscoelasticity as that of the most thermally resistant silicone rubber at room temperature. However, silicone rubber only retains its viscoelasticity between –55 °C and 300 °C. The new material remains flexible over a much higher temperature range, can recover its shape after being repeatedly deformed and shows excellent fatigue resistance. According to the team, the network is highly stable over a broad temperature range thanks to the energy dissipated as the individual nanotubes zip and unzip at the points of contact. The carbon nanotubes themselves are also very heat resistant – between 2000 °C and 3000 °C – so an even broader temperature range might be possible for this rubber. The work was performed at the National Institute of Advanced Industrial Science and Technology in Japan. Read More Paper
Posts Tagged ‘Energy’
Nanotube Rubber Stays Stretchy
Posted in Nanotechnology 
Tags: down-at-high, Energy, Individual, National, random-network, rubber-at-room, Technology, temperature 
Comments OffMicelle nanoparticles for FRET-based ratiometric sensing of mercury ions in water, biological fluids and living cells
A fluorescence resonance energy transfer (FRET) based ratiometric sensing system for mercury ions is built in nano-sized core/corona micelles formed by a poly(ethylene oxide)- b -polystyrene diblock copolymer. For this system, a hydrophobic fluorescein derivative (FLS-C12), which serves as the energy transfer donor, is incorporated into the micelle core during the micelle formation; and a spirolactam-rhodamine derivative (RhB-CS) as a probe for mercury ions is located at the micelle core/corona interface. An efficient ring-opening reaction of RhB-CS induced by mercury ions generates the long-wavelength rhodamine B fluorophore which can act as the energy acceptor, affording the micelle nanoparticles the water-dispersible FRET-based ratiometric detection system for mercury ions, with a detection limit of 0.1 µM in water. The donor and the probe fluorophores, with their structure being appropriately modified, can strongly bind (non-covalently) to the specific sites of the micel…
Posted in Nanotechnology Tags: corona-micelles, detection-limit, Energy, ethylene-oxide, mercury-ions, micelle, nano-sized-core, sensing-system, specific, Structure, structure-being, the-specific, transfer-donor, Water Comments OffModeling of epitaxial graphene functionalization
A new model for graphene epitaxially grown on silicon carbide is proposed. Density functional theory modeling of epitaxial graphene functionalization by hydrogen, fluorine, methyl and phenyl groups has been performed, with hydrogen and fluorine showing a high probability of cluster formation in high adatom concentration. It has also been shown that the clusterization of fluorine adatoms provides midgap states in formation, due to significant flat distortion of graphene. The functionalization of epitaxial graphene using larger species (methyl and phenyl groups) renders cluster formation impossible, due to the steric effect, and results in uniform coverage with the energy gap opening.
Posted in Nanotechnology Tags: been-shown, clusterization, Energy, flat-distortion, high-adatom, new-model, phenyl-groups, provides-midgap, renders-cluster, silicon-carbide, steric, the-steric, using-larger Comments OffGraphene supercapacitor sets energy storage record
Graphene continues to live up to its reputation as one of the most useful nanomaterials for near-term applications, this time in the energy storage arena. From EETimes “ Graphene supercapacitor breaks storage record “: Researchers in the US have made a graphene-based supercapacitor that can store as much energy per unit mass as nickel metal hydride batteries—but unlike batteries, it can be charged or discharged in just minutes or even seconds. The new device has a specific energy density of 85.6 Wh/kg at room temperature and 136 Wh/kg at 80
Posted in Nanotechnology Tags: electric-double, Energy, highest, highest-ever, its-reputation, mass-as-nickel, minutes-or-even, much-energy, Nano, NANOTECH, Nanotechnology, nickel-metal Comments OffHow To Fracture A Shear Thickening Fluid
. Hit it hard, and it will fracture like a solid; but tilt it slowly, and it will flow like a fluid. This is the intriguing property of a type of complex fluid being researched by scientists at The University of Nottingham, the University of Edinburgh, and Politecnico di Torino. The team has used new methods to try to understand the flow properties of these concentrated solutions of particles. “Our observation of the fluid with a high speed camera revealed some intriguing effects depending on the concentration of particles and the speed at which the plates were moved,” says Michael Smith. “At low velocities the fluid is observed to behave like a liquid but at higher velocities and concentrations of particles the fluid can actually fracture like a solid.” “This happens if you dissolve a large amount of cornflour in some water, for example. The high concentration of tiny particles inside the fluid jam into one another forming clusters which lock solid if disturbed at a high enough speed.” “It is a bit like trying to move through a street crowded with an enormous number of people. If you move slowly enough you can make progress and the crowd and you ‘flow.’ However, if you try and sprint down the street you will just knock into so many people that you’ll never be able to move at the speed you want to and hence everything becomes gridlocked.” The research shows that while many features of this kind of system were independent of the geometry of the flow, some effects due to the exposed fluid surface were much more important than previously thought. In particular, an effect known as dilatancy , in which some of the particles poke through the surface of the liquid, was found to play a crucial role in the particles jamming. “The most incredible results were observed when the fluid was stretched at a velocity just below that required to form a jammed fluid,” says Smith. “The fluid was found to form a thin filament which narrowed until it was about hundred particles in diameter. At this point the fluid was observed to recoil elastically, like a rubber band! This is particularly fascinating since the particles are specifically designed to behave like hard spheres with no attractive forces. Where does the elasticity come from? The liquid drains from the filament faster than the particles causing them to poke through the surface as before,” he adds. “The liquid surface forms a meniscus around the particles. It is this curved surface of the fluid which the researchers believe stores the energy and results in the unusual behavior.” Read More Read More Paper
Posted in Nanotechnology Tags: concentration, Energy, Flow, Fluid, geometry, Particles, speed, street, Surface, the-fluid, University Comments OffThe properties of fullerenes encourages its use in solar cells
Researchers at the Universite de Pau et des Pays de I’Adour in France have recently found a simple and better way of polymerizing fullerene. This polymerized fullerene then can be used in a number of applications including solar cells. Using the technique, plastic solar cells can be made at much cheaper cost than the conventional
Posted in Nanotechnology Tags: better-way, conventional, Energy, france, fullerene-then, including-solar, made-at-much, much-cheaper, polymerized, Technique, the-conventional, the-technique, Université, using-the-technique Comments OffIridescent Glass Reflects UV or Infrared Light
Using nanocrystals of cellulose, the main component of pulp and paper, researchers at the University of British Columbia ( UBC ), Canada, have created glass films that have applications for energy conservation in buildings, because of their ability to reflect specific wavelengths of light, such as ultra violet, visible or infrared. These nanoporous films may also be used in optical filters, sensors, or for molecule separation in the pharmaceutical industry. “This is the first time that the unique, helical structure of cellulose has been replicated in a mineral,” says Mark MacLachlan, associate professor at UBC . “The films have many applications and we created them from an exciting new product derived from our wood processing industry right here in British Columbia.” The UBC researchers mixed the cellulose from the wood pulp with a silica, or glass, precursor and then burned away the cellulose. The resulting glass films are composed of pores, or holes, arranged in a helical structure that resembles a spiral staircase. The pores in the helix give the films a wide range of applications. When certain liquids are added to the film, the liquid gets trapped in the pores and changes the optical properties of the films. To reduce the energy needed to cool buildings, windows could be treated with the transparent films that reflect infrared light – the light that heats up a building. Their work was published today, in Nature . Read More Paper
Posted in Nanotechnology Tags: been-replicated, british, Cellulose, Energy, Light, Pharmaceutical, product-derived, published-today, Unique Comments OffDevices with atomically smooth surfaces could change modern electronics
Foresight’s major interest is the transformations in human life that will made made possible by general purpose systems for the atomically precise fabrication of a wide range of products. Although we will probably have to wait two or three decades for such systems to be developed (unless a major effort is mounted to do it sooner), the following item shows that current advances in nanoscience leading to producing microscale atomically precise surfaces already hold the promise of revolutionary adances in important technologies—in this case electronics technologies. From Oregon State University “ Advance Could Change Modern Electronics “: Researchers at Oregon State University have solved a quest in fundamental material science that has eluded scientists since the 1960s, and could form the basis of a new approach to electronics. The discovery, just reported online in the professional journal Advanced Materials, outlines the creation for the first time of a high-performance “metal-insulator-metal” diode. “Researchers have been trying to do this for decades, until now without success,” said Douglas Keszler, a distinguished professor of chemistry at OSU and one of the nation’s leading material science researchers. “Diodes made previously with other approaches always had poor yield and performance. “This is a fundamental change in the way you could produce electronic products, at high speed on a huge scale at very low cost, even less than with conventional methods,” Keszler said. “It’s a basic way to eliminate the current speed limitations of electrons that have to move through materials.” A patent has been applied for on the new technology, university officials say. New companies, industries and high-tech jobs may ultimately emerge from this advance, they say. … Journal Reference ( courtesy of Science Daily ): E. William Cowell, Nasir Alimardani, Christopher C. Knutson, John F. Conley, Douglas A. Keszler, Brady J. Gibbons, John F. Wager. Advancing MIM Electronics: Amorphous Metal Electrodes. Advanced Materials, 2010; DOI: 10.1002/adma.201002678 . At least for the moment, the full text PDF is available at: http://onlinelibrary.wiley.com/doi/10.1002/adma.201002678/pdf .
Posted in Nanotechnology Tags: amorphous-metal, electronics, Energy, Modern, NANOTECH, Oregon, PDF., Professional, Reference, Research, Science, since-the-1960s, transformations, University, wager-advancing Comments OffSustained smooth dynamics in short-sleeved nanobearings based on double-walled carbon nanotubes
We carry out a molecular dynamics study of nanobearings based on double-walled carbon nanotubes with a short rotating outer tube. A (4, 4)/(9, 9) bearing configuration shows peculiar stabilization of rotational motion at certain values of angular velocities. The observed trend is found at those values of initial angular velocities (in the current context, 0.8–1.5 rad ps − 1 ) which denote a transitional regime between nearly frictionless operation at low initial angular speeds and decaying performance at high initial angular velocities. With the use of detailed ‘principal components analysis’, we find that the energy dissipation occurs mainly due to the excitation of wavy modes in the inner tube of the bearing. It is also proposed that wavy deformation is facilitated by the actuation of axial translation of the outer tube, which acts as an energy channelling mode. Hence, we find that the absence of dissipative wavy modes results in sustained smooth rotational dynamics o…
Posted in Nanotechnology Tags: absence, Actuation, angular-speeds, based-on-double, certain-values, Current, Energy, excitation, initial-angular, observed-trend, short-rotating, shows-peculiar, the-actuation, the-excitation, wavy-modes Comments OffSolar harvest
The first observations of the photoelectric effect date back to the early 19th century from work by Alexandre Edmond Becquerel, Heinrich Hertz, Wilhelm Hallwachs and J J Thomson. The theory behind the phenomena was clarified in a seminal paper by Einstein in 1905 and became an archetypical feature of the wave–particle description of light. A different manifestation of quantised electron excitation, whereby electrons are not emitted but excited into the valence band of the material, is what we call the photoconductive effect. As well as providing an extension to theories in fundamental physics, the phenomenon has spawned a field with enormous ramifications in the energy industry through the development of solar cells. Among advances in photovoltaic technology has been the development of organic photovoltaic technology. These devices have many benefits over their inorganic counterparts, such as light-weight, flexible material properties, as well as versatile materials’ synt…
Posted in Nanotechnology Tags: Development, Energy, Material, Phenomena, PHENOMENON, photoelectric, seminal-paper, the-development, the-phenomenon, valence Comments Off