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Nanotechnology Spotlight

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Showing Spotlights 57 - 64 of 388 in category Fabrication Technologies and Devices (newest first):

 

Just say no to cracks

cracksed_nanofilmOne way to use engineered nanoparticles in the real world is in thin films. Such nanoparticulate films are thin layers, sometimes only a few nanometers thick, of composite materials that contain nanoparticles. These new materials have a wide range of applications in drug delivery, nanoelectronics, magnetic storage devices, sensors, or optical coating. However, most processes used to fabricate thin nanocomposite films with high nanoparticle fillings suffer from random nanoparticle agglomeration causing formation of irregularly shaped nanostructured features within the composite. Another complication arises from cracks that develop during the fabrication of the films. Researchers have now described a simple method for fabricating thick, crack-free silica nanoparticle films by subsequent deposition of thin, crack-free silica nanoparticle multilayers.

Posted: Sep 26th, 2012

Researchers are getting closer to making artificial nacre

nacreThe remarkable properties of some natural materials have motivated many researchers to synthesize biomimetic nanocomposites that attempt to reproduce Nature's achievements and to understand the toughening and deformation mechanisms of natural nanocomposite materials. One of the best examples is nacre, the pearly internal layer of many mollusc shells. CaCO3 has long been considered to be a genuine chemical component to approximate nacre. However, only supported polycrystalline CaCO3 (calcite) films have been reported so far. With rapid advancement of nanotechnology, it would be highly desirable to synthesize freestanding CaCO3 tablet building blocks in large quantities, ideally identical or similar to those in natural nacre, using solution-based methods. Now, for the first time, scientists have devised a facile chemical method to synthesize single-crystalline CaCO3 nanotablets in large quantities and provided genuine primary building blocks for the fabrication of nacreous inorganic-organic hybrids.

Posted: Sep 20th, 2012

A lithography technique for fabricating complex, free-floating protein structures

microstructureMultiphoton lithography (MPL) is a microfabrication technique used to create three-dimensional microscale objects with complex geometrical arrangements. Of the various chemistries used to produce solid forms in MPL, protein photocrosslinking has been of particular value in biological applications. In new work, researchers have now described a strategy for creating a nearly unlimited range of microforms from crosslinked protein, including structures composed of multiple proteins. They also describe MPL microfabrication of complex unconstrained objects using high-viscosity protein-based reagents. To avoid drift during fabrication of microforms that are not in integral contact with a surface, the team developed a methodology for producing high-viscosity protein-based reagents, or "protogels". These materials allow the fabrication of protein-based objects that retain rotational and translational degrees of freedom.

Posted: Sep 6th, 2012

Highly asymmetric line nanopatterning becomes possible with block copolymer self-assembly

nanopatternsLithography based on block copolymer self-assembly has received significant attention due to the ability to achieve morphologies with dimensions in the range of 10 to 20 nm or even below. Block copolymer lithography is a cost-effective, parallel, and scalable nanolithography for densely packed periodic arrays of nanoscale features, whose typical dimension scale is beyond the resolution limit of conventional photolithography. Researchers have now introduced a conceptually new and versatile strategy to achieve asymmetric line patterns. This is the first work to demonstrate that highly asymmetric line nanopatterning is possible even though a block copolymer self-assembly technique is used.

Posted: Sep 5th, 2012

Unique porous carbon spheres made by ultrasonic spray pyrolysis

carbon_nanospheresUltrasonic spray pyrolysis (USP) has been widely used in industry for spherical solid powder production, particularly of metal oxides. For some applications, though, porous particles are more desirable than dense ones. Back in 2005, researchers developed a technique to synthesize porous micro- and nanoparticles via USP. This method has since been expanded to prepare porous carbon microspheres. The high surface area and unique porous structures suggest that porous carbon spheres can be useful for electrode materials, adsorbents, and catalyst supports. Researchers at the University of Illinois already demonstrated the use of carbon microspheres as supercapacitors. Now, the team has expanded the aerosol synthesis of porous carbon materials by the use of energetic carbon precursors. Some of the resulting porous carbon spheres exhibit unique and unprecedented morphologies.

Posted: Sep 3rd, 2012

Novel nanoparticle synthesis method improves coatings for smart windows

smart_windowBuildings and other man-made structures consume as much as 30-40% of the primary energy in the world, mainly for heating, cooling, ventilation, and lighting. 'Smart' windows are expected to play a significant role in reducing the energy consumption of homes in two ways: by generating energy themselves; and by providing better insulation by allowing light in and keeping the heat out (in hot summers) or in (in cold winters). Vanadium dioxide (VO2) has long been recognized as a a material of significant technological interest for optics and electronics and a promising candidate for making 'smart' windows: it can transition from a transparent semiconductive state at low temperatures, allowing infrared radiation through, to an opaque metallic state at high temperatures, while still allowing visible light to get through. In new work, researchers have now offered a simple method for promoting the production of monoclinic VO2 nanoparticles by doping.

Posted: Aug 27th, 2012

Unique nanosieves with straight sub-10 nm nanopores

nanoporeMicro- and nanoporous materials can widely be found in nature, be it zeolite minerals, cell membranes, or diatom skeletons. Researchers are developing artificial analogues of such materials, i.e. nanoporous materials, for industrial applications in areas such as catalysis, water purification, environmental clean-up, molecular separation and proton exchange membranes for fuel cells. Manufacturing nanosieves with straight nanopores is still challenging, especially when the pore size is less than 10 nm. Researchers in Korea have now developed a novel material and fabrication technique that allows easy fabrication of nanosieves with sub-10 nm nanopores with straight pore-structure. With it, controlling the pore size from sub-nm to 5 nm becomes very easy.

Posted: Aug 24th, 2012

A sub-10 nm nanopore template for nanotechnology applications

nanoporesNanoporous alumina membranes are used in a wide range of applications, from photonics and sensors to bioelectronics or filtration membranes, since they are basically a 'universal' mold for making zero- or one-dimensional nanostructures of mostly any material or compound. With current fabrication processes, the main limitations of porous alumina templates are their pore size, which cannot be smaller than 25nm, and their polydomain structure, which prevents the possibility of addressing each nanopore individually for electronics applications. A new nanofabrication process by researchers from France and Germany allows to reduce the pore diameter while maintaining the self-ordering and keeping the lattice constant. This led to a new family of AAO templates with identical pores with a diameter below 10nm and a porosity of 3.5%.

Posted: Aug 6th, 2012