Developing chemicals, molecular precursors, and industrial products from petroleum resources is a conventional practice. Plastics, detergents, even pharmaceuticals are derived from petrochemicals. With an increasing focus on the economic and environmental issues associated with the processing of petroleum-based chemicals, scientists are seeking for alternative routes to develop molecules from naturally available plant or crop-based raw materials. Particularly interesting for the fields of nanotechnology is the design and development of soft nanomaterials from renewable sources. Generating these materials from renewable resources could have a significant impact on production technologies and economies.
The ability to extract, dispense and manipulate very small amounts of liquids on the micro- and nanoscale is important in biotechnology, chemistry and also for patterning inorganic, organic and biological inks. Several methods for dispensing liquids exist, but many require complicated electrodes and high-voltage circuits. Researchers in Italy have now demonstrated a pyroelectrohydrodynamic droplet dispenser based on pyroelectric forces.Researchers in Italy have developed and demonstrated a completely new method for extracting and dispensing very small amounts of liquid - as small as few attoliters - from liquid droplet reservoirs or thin liquid films by a method called pyroelectrohydrodynamic (Pyro-EHD).
Steel is one of the most widely used engineering materials in the world. Its pre-eminent position amongst the engineering materials arises due to the abundance and low cost of its main constituent, i.e. iron, and its amenability to produce a wide variety of engineered microstructures with superior properties, and recyclability. Currently, there is a growing awareness about the potential benefits of nanotechnology in the modern engineering industry, and a number of leading research institutes and companies are pursuing research in the area of nanostructured steels. The focus of the ongoing efforts has been largely manipulation of microstructures at the nano-scale through innovative processing techniques and adoption of novel alloying strategies.
OLEDs - organic light-emitting diodes - are full of promise for a range of practical applications. OLED technology is based on the phenomenon that certain organic materials emit light when fed by an electric current and it is already used in small electronic device displays in mobile phones, MP3 players, digital cameras, and also some TV screens. With more efficient and cheaper OLED technologies it will possible to make ultra flat, very bright and power-saving OLED televisions, windows that could be used as light source at night, and large-scale organic solar cells. In contrast to regular LEDs, the emissive electroluminescent layer of an OLED consists of a thin-film of organic compounds. Exciton quenching and photon loss processes still limit OLED efficiency and brightness. Organic light-emitting transistors (OLETs) are alternative, planar light sources combining, in the same architecture, the switching mechanism of a thin-film transistor and an electroluminescent device. Thus, OLETs could open a new era in organic optoelectronics and serve as test beds to address general fundamental optoelectronic and photonic issues.
Material scientists have been fascinated by spider silks for a long time - ultra-strong and extensible self-assembling biopolymers that outperform the mechanical characteristics of many synthetic materials, including steel. While the source of these unique material properties are thought to lie in the distinct protein structures found in spider silk, the physical mechanisms behind them have remained poorly understood for decades. This is partly due to the fact that structural models of spider silk with atomic-level resolution have not been available, preventing a molecular-level analysis. So far, only small models of isolated crystalline domains of silk have been reported. Yet, the integrated structure of the semi-amorphous regions combined with crystalline domains in silk is critical for properties such as toughness and fracture mechanisms. To unravel silk's secrets and ultimately be able to create synthetic materials that duplicate, or even exceed, the extraordinary properties of natural silk, researchers need to fully understand the links between genetic makeup, chemical interactions, and structure, as well as its macroscale mechanical properties.
Controllable fabrication of complex, three-dimensional (3D) nanoscale structures remains a difficult challenge. Researchers are experimenting with a wide range of nanofabrication techniques, from top-down approaches such as mechanical machining to biomimetic replication of complex biotemplates to bottom-up fabrication using anisotropic self-assembly systems - to just name a few examples. New work at Johns Hopkins University utilizes the extrinsic stresses that develop during thin-film deposition - but can also be induced by external forces post-deposition - for the self-assembly of 3D curved and simultaneously patterned structures. This technique is fairly simple and low-cost since it requires only thermal evaporation and low temperature processing; the stress for self-assembly can be controlled to occur only when required. Furthermore, the layers that are selected for 3D structuring can also easily be patterned with conventional electron-beam lithographic processing.
Silver nanoparticles can now be found in all kinds of products, from socks to food containers to coatings for medical devices. Valued for its infection-fighting, antimicrobial properties, silver, in its modern incarnation as silver nanoparticles, has become the promising antimicrobial material in a variety of applications because the nanoparticles can damage bacterial cells. Due to their plasmonic properties and easy surface chemistry silver nanoparticles are also beginning to attract interest among nanomedicine researchers. However, the surface chemistry of nanoparticles that governs their interactions with other constituents in their environment has critical importance. Therefore, chemically altering the surface properties of nanoparticles with polymers, biological ligands and macromolecules is actively being explored.
Researchers have been exploring boron nitride (BN) nanomaterials - from nanotubes to nanosheets and nanoribbons - and found similarities, but also differences to the the properties of the corresponding carbon nanomaterials. Motivated by the outstanding properties of graphene, the boron nitride single layer - a structural analogy of graphene - has been extensively studied both theoretically and experimentally, and has been experimentally realized. However, BN nanomaterials are wide-band-gap semiconductors, and their band structures are rather robust, and difficult to modulate, which is a substantial obstacle for their applications in nanoelectronic devices. Researchers have now shown that hydrogenation might be a simple approach to tune the band structure of graphene-like boron nitride structures.