Showing Spotlights 825 - 832 of 2203 in category All (newest first):
In order to fabricate stimuli-responsive materials, researchers have shown a lot of interest in asymmetric materials such as modulated gels which consist of a controlled layer that is responsive to an environmental stimuli and a nonresponsive substrate layer. And while much effort has gone into creating free-standing films through layer-by-layer (LbL) assembly, relatively little attention has been paid to the asymmetric properties or functionalization of the two surfaces of such free-standing layer-by-layer films. In new work, researchers have now reported the fabrication of asymmetric free-standing layer-by-layer film with asymmetric wettability - one surface is superhydrophobic and the other one is hydrophilic. The superhydrophobic side is water-repellent while the hydrophilic side can absorb/desorb water easily.
Oct 29th, 2012
Sensitive electronic devices like cell phones and computers require shielding from electromagnetic interference (EMI). Such shielding - which must be electrically conductive - has traditionally been made of metal, which poses a weight problem in the push to miniaturize and lighten electronics. Previous research has already demonstrated that ultra-lightweight carbon nanostructure-based nanocomposite materials outperform conventional metal shielding due to their light weight, resistance to corrosion, flexibility, and processing advantages. In new work, scientists in Korea have now demonstrated that single-layer graphene is an excellent choice of material for high-performance EMI shielding. They found that CVD-synthesized graphene shows more than seven times greater EMI shielding effectiveness (in terms of dB) than gold film of the same thickness.
Oct 25th, 2012
Nanostructured surfaces with special wetting properties can not only efficiently repel or attract liquids like water and oils but can also prevent formation of biofilms, ice, and other detrimental crystals. Such super- and ultrahydrophobic surfaces also hold the promise of significantly improving performance of condensers, which could boost the efficiency of most power plants in the world. A critical part of designing such surfaces is 'seeing' how water and other liquids interact when in contact with them. Since these surfaces are made of nanostructures, scientists need to use an electron microscope to image these interactions. In new work, researchers have developed a method for directly imaging such interfacial regions with previously unattainable nanoscale resolution.
Oct 24th, 2012
A new report, which reviews the history of nanotechnology research and development at NASA over the past 15 years, shows that NASA is the only U.S. federal agency to scale back investment in this area. The study argues that nanotechnology has the proven capability of revolutionizing most areas of technology that will be critical to NASA's future missions: The agency needs a bolder plan for R+D to match the requirements of those missions and to recapture its place at the forefront of nanotechnology. But it's not as if NASA doesn't have any ideas as to how nanotechnologies could be used to advance space technologies. In 2010, the agency drafted a 20-year Nanotechnology Roadmap as part of its integrated Space Technology Roadmap. According to this document, nanotechnology can have a broad impact on NASA missions.
Oct 23rd, 2012
By exploiting the outstanding properties of self-organizing materials, a team of Italian scientists has investigated a new way to build a bridge between two branches of physics: 'hard matter' and 'soft matter'. This allows researchers to address specific issues towards the realization of active-plasmonics devices, where the plasmonic resonance of gold nanoparticles can be finely controlled by means of external perturbations (electrical field, optical field, temperature). In place of a static approach - e.g. varying particles size, materials, etc. - the researchers used liquid crystals as active surrounding medium. This approach represents a 'scientific wedding' between the fascinating worlds of soft matter and plasmonics worlds.
Oct 22nd, 2012
Nanoscale materials like quantum dots, carbon nanotubes, graphene, or nanowires, have intriguing properties, but unless they can be assembled in to larger structures it is difficult to take advantage of these properties. Figuring out how to assemble nanostructures into functional macroscale assemblies is one of the key challenges that nanoscientists around the world are faced with. In the area of nanowires, this has led to researchers exploring various nanowire assembly techniques ranging from Langmuir Blodgett alignment to electrospinning. Researchers have now developed a novel approach for assembling nanowires into macroscopic yarns that consist of millions of nanowires bundled together. The team found that light can be used to charge inorganic semiconducting nanowires. Once charged, the nanowires can be manipulated with electric fields.
Oct 18th, 2012
The idea of using laser light to trap or levitate small particles goes back to the pioneering work by Arthur Ashkin of Bell Laboratories in the 1970s and 1980s. Ashkin found that radiation pressure - the ability of light to exert pressure to move small objects - could be harnessed to constrain small particles. This discovery has since formed the basis for scientific advances such as the development of optical tweezers, which are frequently used to control the motion of small biological objects. However, optical trapping of nanoparticles remains a challenging task because the forces are often too small when the sizes of the objects are reduced to the nanometer scale. New findings from scientists at Lawrence Berkeley National Laboratory and National University of Singapore fill a gap and also open the door to new discoveries by demonstrating trapping and manipulating nanometer size particles using an electron beam instead of optical forces. It could also lead to new force spectroscopy where nanostructures can be assembled one nanoparticle at a time.
Oct 16th, 2012
The heating properties of iron oxide nanoparticles have been exploited through the years for use in cancer therapy, gene regulation, and temperature responsive valves. These applications have demonstrated the versatility of iron oxide nanoparticles, but they had rarely, if ever, been used to enhance the activity of thermophilic enzymes. Thermophilic enzymes are highly stable biomolecular systems that are excellent tools due to their thermostability and long-term activity for extended lifetime uses in the field and other applications. New work by researchers in the U.S. addresses the problem of remotely activating biological materials with a higher efficiency than conventional methods such as water baths or convection ovens.
Oct 15th, 2012