Nanowerk March 9, 2020 To make 2D metals key ingredients in next-generation quantum and optoelectronic devices they must be stabilized against environmental degradation and integrated into heterostructure devices at the wafer scale. A team of researchers in the US (Pennsylvania State University, Lawrence Berkeley National Laboratory, Oak Ridge National Laboratory) has demonstrated large-area, environmentally stable, single-crystal 2D gallium, indium and tin that are stabilized at the interface of epitaxial graphene and silicon carbide. The 2D metals are covalently bonded to SiC below but present a non-bonded interface to the graphene overlayer; that is, they are ‘half van der Waals’ metals […]
Category Archives: Advanced materials
Scientists create new material for electronics of the future
Phys.org February 27, 2020 Barium ferrites are particularly interesting because they have unique functional properties. Researchers in Russia have created barium hexaferrite with various degrees of aluminum doping as their crystal structure allows to vary the properties of the material in the ranges needed for a particular device. They are studying the properties of the material in the frequency range of 32-50 GHz. It allows increasing the frequency range used in the production of electronic devices. Using powder form of the material they have shown that increases electronic device operational stability and reduces the cost of sintering. It can be […]
A megalibrary of nanoparticles
Nanowerk January 23, 2020 There is a lot of interest in the world of nanoscience in making nanoparticles that combine several different materials. But the current process is complex, long and time consuming. Researchers at the Pennsylvania State University have developed two design guidelines, based on interfacial reactivity and crystal structure relations that enable the rational synthesis of a heterostructured nanorod megalibrary. They defined synthetically feasible pathways to 65,520 distinct multicomponent metal sulfide nanorods having as many as 6 materials, 8 segments, and 11 internal interfaces by applying up to seven sequential cation-exchange reactions to copper sulfide nanorod precursors. They […]
Carbon nanotube film produces aerospace-grade composites with no need for huge ovens or autoclaves.
MIT News January 13, 2020 A team of researchers in the US (MIT, industry) utilized a nanomaterial with morphology‐controlled nanoscale capillaries to manufacture aerospace‐grade advanced carbon fiber composites without utilizing pressure from an autoclave. They demonstrated that the capillary pressure from a nanoporous film replaces the need for applied pressure to manufacture void‐free layered polymeric architectures. The nanomaterial‐enabled capillary pressure is quantified as 50% greater than typical pressures used in such processing. The technique may help to speed up the manufacturing of airplanes and other large, high-performance composite structures, such as blades for wind turbines…read more. TECHNICAL ARTICLE
Engineers develop ‘chameleon metals’ that change surfaces in response to heat
Phys.org January 13, 2020 Researchers at Iowa State University started with a liquid metal alloy of gallium, indium and tin synthesized into particles covered with a smooth oxide shell that has been chemically stabilized. As the particles are heated, the surface thickens and stiffens and begins to behave more like a solid. Eventually the surface breaks, allowing the liquid metal inside to come to the surface. The most reactive, gallium, breaks through first. More heat brings indium to the surface. And the highest heat—about 1,600 degrees Fahrenheit—brings out florets of tin. Time, temperature and oxygen levels are carefully controlled by […]
An 18-carat gold nugget made of plastic
EurekAlert January 8, 2020 Researchers in Switzerland have developed a material via a hydrogel precursor dried into an aerogel. Annealing of the polystyrene matrix under vacuum gives rise to a homogeneous template. The final apparent density and porosity of the material depend directly on the volumetric concentration of the starting solution used for hydrogel formation. After annealing, a homogeneous microstructure is obtained in which the shining gold single crystal platelets are evenly embedded in a polystyrene matrix. The material has a glass transition temperature of ≈105 °C, the Young’s modulus of the material with a density of 1.7 g cm−3 […]
Using a material’s ‘memory’ to encode unique physical properties
Science Daily December 20, 2019 A team of researchers in the US (University of Chicago, University of Pennsylvania) has shown that aging encodes a memory of the stresses imposed during preparation. Because of inhomogeneous local stresses, the material itself decides how to evolve by modifying stressed regions differently from those under less stress. Because material evolution occurs in response to stresses, aging can be “directed” to produce sought-after responses and unusual functionalities that do not inherently exist. Aging obeys a natural “greedy algorithm” as, at each instant, the material simply follows the path of most rapid and accessible relaxation. Their […]
A self-cleaning surface that repels even the deadliest superbugs
EurekAlert December 13, 2019 Researchers in Canada have developed a plastic surface that can be shrink-wrapped onto door handles, railings, IV stands and other surfaces that can be magnets for bacteria such as MRSA and C. difficile. The surface is also treated chemically to further enhance its repellent properties, resulting in a barrier that is flexible, durable and inexpensive to reproduce. It works through a combination of nano-scale surface engineering and chemistry. The surface is textured with microscopic wrinkles that exclude all external molecules. A drop of water or blood or bacteria bounces away when it lands on the surface. […]
Novel material switches between electrically conducting and insulating states
Nanowerk December 4, 2019 Researchers at Northwestern University designed the picoscale crystalline structure of molybdenum oxynitride (MoON), to host the phase transition. The researchers found the metal-insulator transition (MIT) occurred near 600 degrees Celsius, revealing its potential for applications in high-temperature sensors and power electronics. They noted multiple design parameters influenced MoON’s phase transition. The inclusion of multiple anions in the material activated the phase transition due to specific electron configurations related to the spatial orientation of electronic orbitals. The findings offer insight into how subtle changes on the nanoscale can be used to control macroscopic behavior, like conductivity, in […]
Metal-organic framework captures and converts toxic air pollutant into industrial chemical
Nanowerk November 23, 2019 An international team of researchers (UK, USA – Oak Ridge National Laboratory, Lawrence Berkeley National Laboratory) has developed an MOF, denoted as MFM-520, that can capture atmospheric nitrogen dioxide at ambient pressures and temperatures—even at low concentrations and during flow—in the presence of moisture, sulfur dioxide and carbon dioxide. Despite the highly reactive nature of the pollutant, MFM-520 proved capable of being fully regenerated multiple times by degassing or by treatment with water from the air—a process that also converts nitrogen dioxide into nitric acid. The highest rate of NO2 uptake by this material occurs at […]