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Lawrence Livermore National Laboratory (LLNL) scientists have created vertically aligned single-walled carbon nanotubes on metal foils that could be a boon for energy storage and the electronics industry.

Vertically aligned carbon nanotubes (VACNTs) have exceptional mechanical, electrical and transport properties in addition to an aligned architecture, which is key for applications such as membrane separation, thermal management, fiber spinning, electronic interconnects and energy storage.

To date, widespread integration of VACNTs into next-generation technologies is thwarted by a lack of compatible, economic, mass-production capabilities. High-quality VACNTs are typically made on substrates such as silicon (Si) or quartz wafers that are rigid, expensive and electrically insulating.

Experiments suggest that hydrogen bonding explains why a wet surface can have nearly twice as much friction as a dry surface.

A wet floor poses a risk for slipping, but in certain cases, water added to a surface can increase friction. Researchers have now found that this phenomenon is partly explained by hydrogen bonds between the water and the surface, an effect that was not previously thought to play an important role [1]. The team reached this conclusion by studying the friction between two silicon surfaces under a range of wetness conditions. The researchers showed that heavy water produces greater friction than normal water—evidence that hydrogen bonding has an influence. The results could lead to a deeper understanding of the effects of humidity on friction.

The earliest friction studies looked at relatively large objects, such as a wood block sliding down an inclined surface. More recent efforts have focused on the nanoscale, exploring the friction forces on needle-like probes. These latter experiments have identified the friction mechanisms that operate at a single microscopic bump, or “asperity,” on a surface. But a missing piece is how to relate the friction at nanoscales to that at macroscales, says Liang Peng from the University of Amsterdam.

Superconducting nanotechnology is a rapidly developing field with a series of promising applications in the field of new quantum technologies such as advanced superconducting quantum processors based on qubits with Josephson tunnel junctions.

Recently, an international team of researchers – with participation of Leibniz Institute of Photonic Technology (Leibniz IPHT) – has demonstrated and published yet another quantum mechanical effect in superconductors – the photon assisted coherent quantum phase slip effect in a very thin superconducting nanowire. The effect is revealed as the formation of current steps on the current-voltage characteristic subject to microwave radiation (Nature, “Quantized current steps due to the a.c. coherent quantum phase-slip effect”).

This effect has been theoretically predicted more than thirty years ago and hints of the current steps of this type have been previously observed in small size Josephson junctions. Switching from a Josephson junction to a superconducting nanowire made of thin films of high-quality niobium nitride allowed the researchers to observe sharp and distinct steps on the current voltage characteristic located at current values I n = 2efn, where 2e is the electric charge of a so-called Cooper pair of two electrons, f the frequency of microwave radiation, and n as an integer number, denoting the step order.

Year 2017 face_with_colon_three

The chronic nature and associated complications of nonhealing wounds have led to the emergence of nanotechnology-based therapies that aim at facilitating the healing process and ultimately repairing the injured tissue. A number of engineered nanotechnologies have been proposed demonstrating unique properties and multiple functions that address specific problems associated with wound repair mechanisms. In this outlook, we highlight the most recently developed nanotechnology-based therapeutic agents and assess the viability and efficacy of each treatment, with emphasis on chronic cutaneous wounds. Herein we explore the unmet needs and future directions of current technologies, while discussing promising strategies that can advance the wound-healing field.

Year 2020 face_with_colon_three

An international team of scientists have restored the vision in blind rats using a nanoparticle-based artificial retina prosthesis that can be injected directly into the eye. The scientific advance has been successfully demonstrated for a period of eight months without the need for surgery. While it is still early days for the research, it suggests it might one day be possible to use the conjugated polymer nanoparticle (P3HT-NP) treatment in humans to correct eye problems –ranging from hereditary retinal dystrophies to the incredibly common age-related macular degeneration.

“In our ‘liquid retina device,’ P3HT nanoparticles spread out over the entire subretinal space and promoted light-dependent activation of spared inner retinal neurons, recovering subcortical, cortical and behavioral visual responses,” Fabio Benfenati, research director at the Italian Institute of Technology, told Digital Trends. “We think that P3HT-NPs provide a new avenue in retinal prosthetics.”

Continue reading “Nanotech Injections Restore Vision In Blind Rats” »

Hunting for lightweight dark matter particles requires detectors with much lower signal thresholds than traditional experiments. This requirement has prompted novel detection techniques, including probing the faint interactions that occur between sub-MeV particles and electrons. In a 180-hour-long experiment, Yonit Hochberg of the Hebrew University of Jerusalem and her colleagues demonstrate a device that distinguishes hypothetical sub-MeV dark matter from background noise with record sensitivity [1]. Their experiment places the strongest constraints yet on interactions between lightweight dark matter and regular matter.

Hochberg and her colleagues etched an array of nanowires in a 7-nm-thick tungsten-silicide film to produce a superconducting nanowire single-photon detector, a sensor that is sensitive to extremely small energy inputs. When energy above some threshold is deposited on a superconducting nanowire, the wire briefly becomes a regular conductor, resulting in a voltage pulse.

The team circulated a fixed current through their device and sealed it in a light-tight box for 180 hours. They counted four voltage pulses, each corresponding to a deposited energy of at least 0.73 eV. Absent any other detectable energy source, these dark counts could be attributed to cosmic-ray-generated muons or high-energy particles excited by radioactive decay.

A research team from Skoltech, Aalto University, and Kurnakov Institute has recently developed a new, versatile and simple approach to using carbon nanotubes for manufacturing carbon nanotube-polymer nanocomposites. The method is reported in Carbon and involves making briquettes—dense packages of carbon nanotube powders. Nanocomposites made with briquettes perform equally well as those made from the more expensive masterbatches, which are also polymer-specific—that is, less versatile.

“We believe the use of dense briquettes of carbon nanotubes can significantly facilitate the development of the carbon nanotube composite industry. This technique is cheap and applicable to a broad variety of polymer matrices, without sacrificing any of the electrical and thermal properties of the final material,” the lead author of the study, Skoltech Ph.D. student Hassaan Butt, stated.

Carbon nanotubes have been intensively investigated for decades by researchers from academia and industry because of their unique combination of electrical, thermal, and mechanical properties. Meanwhile, polymer-based nanocomposites have come to be the largest carbon nanotube application and the one closest to widespread integration into everyday life. It is easy to understand why: The smallest amounts of nanotubes added to a polymer endow the material with fundamentally new properties, such as electrical conductivity and piezoresistivity, as well as crucially enhancing its thermal and mechanical properties.

Lawrence Livermore National Laboratory (LLNL) scientists are scaling up the production of vertically aligned single-walled carbon nanotubes (SWCNT) that could revolutionize diverse commercial products ranging from rechargeable batteries, automotive parts and sporting goods to boat hulls and water filters. The research appears in the journal Carbon.

Most CNT production today is used in bulk composite materials and thin films, which rely on unorganized CNT architectures. For many uses, organized CNT architectures such as vertically aligned forests provide important advantages for exploiting the properties of individual CNTs in macroscopic systems.

“Robust synthesis of vertically-aligned carbon nanotubes at large scale is required to accelerate deployment of numerous cutting-edge devices to emerging commercial applications,” said LLNL scientist and lead author Francesco Fornasiero. “To address this need, we demonstrated that the structural characteristics of single-walled CNTs produced at wafer scale in a growth regime dominated by bulk diffusion of the gaseous carbon precursor are remarkably invariant over a broad range of process conditions.”

Thin films made of carbon nanotubes hold a lot of promise for advanced optoelectronics, energy and medicine, however with their manufacturing process subject to close supervision and stringent standardization requirements, they are unlikely to become ubiquitous anytime soon.

“A major hindrance to unlocking the vast potential of nanotubes is their multiphase manufacturing process which is extremely difficult to manage. We have suggested using artificial neural networks (ANN) to analyze experimental data and predict the efficiency of single-walled carbon nanotubes synthesis,” explains one of the authors of the study and Skoltech researcher, Dmitry Krasnikov.

In their work published in the prestigious Carbon journal, the authors show that machine learning methods, and, in particular, ANN trained on experimental parameters, such as temperature, gas pressure and flow rate, can help monitor the properties of the carbon nanotube films produced.