Researchers at McGill Univ. have succeeded in simultaneously observing the reorganizations of atomic positions and electron distribution during the transformation of the “smart material” vanadium dioxide from a semiconductor into a metal. The observations are made in a time frame a trillion times faster than the blink of an eye.
Researchers in the U.K. have found a new way to make nanostructured carbon using the waste product sawdust. By cooking sawdust with a thin coating of iron at 700 C, they have discovered that they can create carbon with a structure made up of many tiny tubes. These tubes are one thousand times smaller than an average human hair.
Scientists have been able to manufacture 3-D isotropic metamaterials, but up to now only on a very small scale. Now, in a significant breakthrough, scientists from RIKEN, in collaboration with colleagues in Taiwan, have succeeded in creating a large metamaterial up to 4-mm-square in size that is essentially isotropic, using a type of metamaterial element called a split-ring resonator.
Researchers at the New York Univ. Polytechnic School of Engineering have broken new ground in the development of proteins that form specialized fibers used in medicine and nanotechnology. For as long as scientists have been able to create new proteins that are capable of self-assembling into fibers, their work has taken place on the nanoscale. For the first time, this achievement has been realized on the microscale.
A few short years ago, the idea of a practical manufacturing process based on getting molecules to organize themselves in useful nanoscale shapes seemed far-fetched. Recent work at NIST, Massachusetts Institute of Technology and IBM Almaden Research Center suggest this capability isn’t far off, however, by demonstrating self-assembly of thin films on a polymer template that creates precise rows just 10 nm wide.
Scientists at Ames Laboratory have developed deeper understanding of the ideal design for mesoporous nanoparticles used in catalytic reactions, such as hydrocarbon conversion to biofuels. The research will help determine the optimal diameter of channels within the nanoparticles to maximize catalytic output.
DNA has garnered attention for its potential as a programmable material platform that could spawn entire new and revolutionary nanodevices in computer science, microscopy, biology and more. Researchers have been working to master the ability to coax DNA molecules to self-assemble into the precise shapes and sizes needed in order to fully realize these nanotechnology dreams.
Graphene’s exotic properties can be tailored by cutting large sheets down to ribbons of specific lengths and edge configurations. But this “top-down” fabrication approach is not yet practical, because current lithographic techniques always produce defects. Now, scientists from the U.S. and Japan have discovered a new “bottom-up” self-assembly method for producing defect-free graphene nanoribbons with periodic zigzag-edge regions.
As in Alice’s journey through the looking-glass to Wonderland, mirrors in the real world can sometimes behave in surprising and unexpected ways, including a new class of mirror that works like no other. Scientists have demonstrated, for the first time, a new type of mirror that forgoes a familiar shiny metallic surface and instead reflects infrared light by using an unusual magnetic property of a non-metallic metamaterial.
Researchers in Japan have developed a new yet simple technique called "diffusion driven layer-by-layer assembly" to construct graphene into porous 3-D structures for applications in devices such as batteries and supercapacitors. The new method borrowed a principle from polymer chemistry, known as interfacial complexation, to allow graphene oxide to form a stable composite layer with an oppositely charged polymer.
Researchers at Japan’s National Institute of Advanced Industrial Science and Technology have synthesized an atomic chain in which two elements, cesium and iodine, are aligned alternately inside a carbon nanotube. Analyzed using electron microscopy and spectroscopy, the invention could shed light on the adsorption mechanisms of radioactive elements.
Scientists report that they have made the first experimental observation of piezoelectricity and the piezotronic effect in an atomically thin material, molybdenum disulfide. This finding has resulted in a unique electric generator and could point the way to mechanosensation devices that are optically transparent, extremely light, and very bendable and stretchable.
When trying to design a mechanical system to last as long as possible, scientists and engineers have to find ways of overcoming friction. While researchers have found many materials that help to reduce friction, conventional lubricants often have chemical limitations. A recent analysis at Argonne National Laboratory has identified the properties of a newer, wear-resistant substance that works in a broader range of environments.
Inexpensive microrobots capable of probing and manipulating individual cells and tissue for biological research and medical applications are closer to reality with the design of a system that senses the minute forces exerted by a robot's tiny probe. Microrobots small enough to interact with cells already exist. However, there is no easy, inexpensive way to measure the small forces applied to cells by the robots, until now.
Developing the cloak of invisibility would be wonderful, but sometimes simply making an object appear to be something else will do the trick, according to Penn State Univ. engineers. To do this, they employ what they call "illusion coatings," which are made of a thin flexible substrate with copper patterns designed to create the desired result. The metamaterial coatings can function normally while appearing as something else.
A surprising phenomenon has been found in metal nanoparticles: They appear, from the outside, to be liquid droplets, wobbling and readily changing shape, while their interiors retain a perfectly stable crystal configuration. The research team behind the finding says the work could have important implications for the design of components in nanotechnology, such as metal contacts for molecular electronic circuits.
Using a common laboratory filter paper decorated with gold nanoparticles, researchers at Washington Univ. in St. Louis have created a unique platform, known as “plasmonic paper,” for detecting and characterizing even trace amounts of chemicals and biologically important molecules, including explosives, chemical warfare agents, environmental pollutants and disease markers.
Researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard Univ. have unveiled a new method to form tiny 3-D metal nanoparticles in prescribed shapes and dimensions using DNA, nature's building block, as a construction mold. The ability to mold inorganic nanoparticles out of materials such as gold and silver in precisely designed 3-D shapes is a significant breakthrough.
A long-sought goal of creating particles that can emit a colorful fluorescent glow in a biological environment, and that could be precisely manipulated into position within living cells, has been achieved by a team of researchers at Massachusetts Institute of Technology and several other institutions. The new technology could make it possible to track the position of the nanoparticles as they move within the body or inside a cell.
Researchers have developed a new method for harvesting the energy carried by particles known as “dark” spin-triplet excitons with close to 100% efficiency, clearing the way for hybrid solar cells which could far surpass current efficiency limits. To date, this type of energy transfer had only been shown for “bright” spin-singlet excitons.
It’s a well-known phenomenon in electronics: Shining light on a semiconductor, such as the silicon used in computer chips and solar cells, will make it more conductive. But now researchers have discovered that in a special semiconductor, light can have the opposite effect, making the material less conductive instead. This new mechanism of photoconduction could lead to next-generation excitonic devices.
Nanoparticles could revolutionize the medical industry, but they must first target a specific region in the body, be trackable, and perform their function at the right moment. Researchers in Japan have made progress in this direction with a new type of nanomaterial: the nanosheet. Specifically, they have designed a strong, stable and optically traceable smart 2-D material that responds to pH, or the acidity or basicity of its environment.
Arrays of tiny conical tips that eject ionized materials are being made at the Massachusetts Institute of Technology. The technology, which harnesses electrostatic forces, has a range of promising applications, such as spinning out nanofibers for use in “smart” textiles or propulsion systems for fist-sized “nanosatellites.” The latest prototype array that generates 10 times the ion current per emitter that previous arrays did.
Nanostructures of virtually any possible shape can now be made using a combination of techniques developed to exploit the unique properties of so-called perovskites. The group based in the Netherlands, developed a pulsed laser deposition technique to create patterns in ultra thin layers, one atomic layer at a time. The perovskites’ crystal structure is undamaged by this soft lithography technique, maintaining electrical conductivity.
A Duke Univ. team has found that nanoparticles called single-walled carbon nanotubes accumulate quickly in the bottom sediments of an experimental wetland setting, an action they say could indirectly damage the aquatic food chain. According to the research, the risk to humans ingesting the particles through drinking water is slight, but aquatic food chains might be harmed by molecules "piggybacking" on the carbon nanoparticles.