The serious threat of particulate matter (PM) air pollution to human health spurs development of advanced filter technologies. Particular efforts have been made in designing air filters with both high filtration efficiency and low airflow resistance by utilizing carbon nanotubes and electrospun polymer and inorganic nanofibers. In new work, scientists explored the performance of electrospun silk nanofiber membranes as air filters, which showed both of lightweight and high efficient features.
Compared to the conventional inefficient incandescent and fluorescent lighting technologies, LED light bulbs can, in principle, operate at an efficiency level of 100%. The current LED lighting technology, however, is not even close to reaching this limit. This is due to several problems which, however, can be by and large solved by employing tunnel junction integration into current nanowire LED structures. Demonstrating this, researchers have developed tunnel junction nanowire LEDs that can eliminate the use of resistive p-GaN contact layers, leading to reduced voltage loss and enhanced hole injection.
Researchers developed a simple controllable set-up for drawing single filament nanofibers from polymer solutions or melts using a rotating rod or a set of rods (round brush). This method can be used to produce 3D tissue scaffolds by winding nanofibers onto spools of different shapes and dimensions and depositing cells of interest at the same time. The new method, which the scientists named touch-spinning, has excellent control over the fiber diameter and is compatible with all kinds of polymeric materials, polymer melts and solutions, polymer composite materials, and biopolymers.
The most common method for making nanofibers employs electrospinning that uses an electrical charge to draw nanofibers from a polymeric solution. This technique utilizes large voltages and is strongly influenced by the dielectric properties of the material. It is also impossible to electrospin many biopolymers without blending with another polymer. Addressing these drawbacks, a team of researchers report a new method - magnetospinning - which utilizes a simple set-up that is independent of the dielectric constant of the solvent and polymer used.
The use of copper as an alternative electrode material to silver would reduce the cost of conductive inks. Nevertheless, copper nanowire conductors face a serious bottleneck for future practical use in flexible and stretchable optoelectronics: although they are nearly as conductive as silver, this conductivity is not stable. Researchers have now demonstrated conductive copper nanowire elastomer composites with ultrahigh performance stability against oxidation, bending, stretching, and twisting. This material offers a promising alternative as electrodes for flexible and stretchable optoelectronics.
Most printed electronics applications rely on some kind of ink formulated with conductive nanomaterials. Researchers have now introduced a rapid and facile method to fabricate a foldable capacitive touch pad using silver nanowire inks. The team developed a technique that uses a 2D programmed printing machine with postdeposition sintering using a camera flash light to harden the deposited silver nanowire ink. resulting paper-based touchpads produced by direct writing with silver nanowire inks offer several distinct advantages over existing counterparts.
The food chemistry Maillard reaction is responsible for many colors and flavors in foods - roasting of coffee, baking of bread and sizzling of meat. Scientists have made use of this ingenious food chemistry to 'cook' their copper nanowires. This green approach that formulates copper atoms in water to form untangled metallic state nanowires. Naturally, a lingering chocolate-like aroma was detected during the copper nanowires synthesis.
Over the years, researchers have developed a large number of techniques to synthesize nanowires and nanotubes in the laboratory. These procedures vary widely in their hardware requirements and methodology. Nevertheless, they all share a set of common goals: simplicity of protocol; fast execution; and low energy input. Now, an international group of scientists has reported a breakthrough in all three of these areas, leading to a revolutionary and remarkably simple technique for preparing one-dimensional nanostructures. As an example, they demonstrate a unique approach to growing amorphous boron nanowires.