Phys.org July 27, 2021 The structure of a glass closely resembles the liquid phase, but its properties are like solids, akin to a crystal. In vapor deposition, a material is changed from a gas into a solid directly. Researchers at the University of Pennsylvania used vapor deposition to create very dense thin-film glasses, corresponding to the packing of the new liquid phase, with a density much higher than was predicted to be possible without applying immense amounts of pressure. Thin films of these glasses can have density values even higher than crystal. Detailed structural information analysis of how individual molecules […]
Category Archives: Adaptive materials
Low-cost, sustainable, readily available plasma technology could replace one of the world’s rarest materials
Nanowerk July 19, 2021 An international team of researchers (Australia, China) has developed a plasma-generated, hybrid nanocomposite material which is free of indium. They used high power impulse magnetron sputtering (HiPIMS) technology to deposit the internal WO3 layer and the external Ag/WO3 nanocomposite. High rates of silver ionization in the HiPIMS process and energetic arrival of silver ions on the negatively biased dielectric/metal/dielectric structure enabled their penetration into the external tungsten oxide layer, forming a nanocomposite structure in a single-step process. This nanotechnology-enabled approach allows electrochromic devices to change colour efficiently and rapidly upon a user’s request and offers a […]
Microbially produced fibers: Stronger than steel, tougher than Kevlar
Phys.org July 21, 2021 A problem associated with recombinant spider silk fiber is the need to create β-nanocrystals, a main component of natural spider silk, which contributes to its strength. Researchers at Washington University redesigned the silk sequence by introducing amyloid sequences that have high tendency to form β-nanocrystals. They created different polymeric amyloid proteins using three well-studied amyloid sequences as representatives. The resulting proteins had less repetitive amino acid sequences than spider silk, making them easier to be produced by engineered bacteria. The longer the protein, the stronger and tougher the resulting fiber. The 128-repeat proteins resulted in a […]
New material could mean lightweight armor, protective coatings
Science Daily July 19, 2021 An international team of researchers (USA – MIT, Caltech, Switzerland) has fabricated nanoarchitectured materials, that absorb the impact of microscopic projectiles accelerated to supersonic speeds. According to their calculations the new material absorbs impacts more efficiently than steel, Kevlar, aluminum, and other impact-resistant materials of comparable weight. Tests revealed that consistent mechanisms such as compaction cratering and microparticle capture enable this superior response. They introduced predictive tools for crater formation in these materials using dimensional analysis. These results substantially uncover the dynamic regime over which nanoarchitecture enables the design of ultralightweight, impact-resistant materials that could […]
Researchers identify ultrastable single atom magnet
Phys.org July 7, 2021 An international team of researchers (South Korea, Germany) has shown that dysprosium (Dy) atoms on magnesium oxide (MgO) have a giant (magnet/ic anisotropy energy) MAE of 250 meV, currently the highest among all surface spins. Using a variety of scanning tunnelling microscopy (STM) techniques including single atom electron spin resonance (ESR), they confirmed that there was no spontaneous spin-switching in Dy over days at ≈ 1 K under low and even vanishing magnetic field. They utilized these robust Dy single atom magnets to engineer magnetic nanostructures, demonstrating unique control of magnetic fields with atomic scale tunability. The work […]
New advanced material shows extraordinary stability over wide temperature range
Phys.org June 14, 2021 Researchers in Australia have demonstrated that the zero thermal expansion material made of scandium, aluminum, tungsten, and oxygen did not change in volume from 4 to 1400 Kelvin (-269 to 1126 °Celsius). They confirmed the structural stability of Sc1.5Al0.5W3O12 with only minute changes to the bonds, position of oxygen atoms and rotations of the atom arrangements which appear to be undertaken cooperatively. The crystallographic data from the diffraction experiments reflects the combination of subtle but observable distortions of the polyhedral units, bond lengths, angles and oxygen atoms that allow the material to absorb temperature changes. It […]
Using ‘smart rust’ to mark objects unambiguously and tackle counterfeiting
Nanowerk June 16, 2021 An object can be recycled responsibly only if all raw materials and intermediate products used for manufacturing it is marked unambiguously using a tamper-proof method. Inspired by the variation of a musical ensemble yielding distinguishable overtones, researchers in Germany have developed a magnetic particle-based toolbox that provides more than 77 billion different magnetic codes, adjustable in one single particle, that can be read out unambiguously, easily, and quickly. The variation of the supraparticle composition alters their magnetic overtones. By minimizing magnetic interactions, customizable signals are spectrally decoded by the simple method of magnetic particle spectroscopy. The […]
Novel materials: Sound waves traveling backwards
Nanowerk June 10, 2021 Acoustic waves in gases, liquids, and solids usually travel at an almost constant speed of sound. However, rotons, quasiparticles, are an exception: their speed of sound changes significantly with the wavelength, and it is also possible that the waves travel backwards. Rotons were predicted in 1962 in the context of superfluidity. Until now, they could only be observed under special quantum-physical conditions at very low temperatures – and were therefore not suitable to technical applications. An international team of researchers (Germany, France) propose an artificial material that can produce rotons without any quantum effects under normal […]
A material keyboard made of graphene
Phys.org May 5, 2021 An international team of researchers (Switzerland, Japan) put two layers graphene flakes on top of each other and made a magic angle of exactly 1.06 degrees. The atomic crystal lattices of the graphene flakes created a moiré pattern. They attached several additional electrodes on top of the magic angle graphene flakes to apply an electric voltage to the material. By applying different voltages to the individual electrodes, they turned the magic angle graphene into an insulator in one spot, but a few hundred nanometres to one side it becomes a superconductor. For possible uses in quantum […]
Researchers first to link silicon atoms on surfaces
Nanowerk March 30, 2021 Researchers in Germany have demonstrated Si–Si bond formation on Au(111) and Cu(111) surfaces by using two different monomers, each containing two silicon functional groups (CH3SiH2 or SiH3) attached to an aromatic backbone, leading to polymeric disilenes that interact with the surface. A combination of experimental and theoretical studies corroborated the formation of covalent Si–Si bonds between the long, highly ordered polymer chains with high diastereoselectivity. The reactive Si=Si bonds formally generated via double dehydrogenative coupling were stabilized via covalent Si–surface interaction. This method could be used to develop a completely new strategy for molecular changes to […]