Physics World September 3, 2020 Researchers in Vietnam fabricated moth eye structure on the quartz substrate covered with a flat paraffin layer to isolate it in a cold and humid environment. The paraffin layer only stayed on the top of the nanostructure, separated it from the outside environment to obstruct heat energy being transferred to the cold substrate, and prevented the wetting transition, which was observed regularly on the rough surface. Numerous air blocks trapped inside the nanostructure also contributed to delayed heat transfer, leading to an increase in the freezing time of the attached water droplet. The nanostructure coated […]
Category Archives: Advanced materials
New electronic skin can react to pain like human skin
EurekAlert September 1, 2020 An international team of researchers (Australia, Bangladesh) combined stretchable electronics, temperature-reactive coatings, and brain-mimicking memory to develop a device that can electronically replicate the way human skin senses pain. They have demonstrated the ability to detect and respond to pressure, temperature, and pain stimuli above a threshold with real‐life performance characteristics with explanation of underlying mechanisms. The research opens a way to better prosthetics, smarter robotics and non-invasive alternatives to skin grafts…read more. Open Access TECHNICAL ARTICLE
Double layer of 2D materials unlocks crucial properties
Nanowerk August 10, 2020 The interactions between the different layers in structures, held together by van der Waals forces, can give rise to entirely new properties. An international team of researchers (Switzerland, France, Japan) has succeeded in creating such a structure using double layer of molybdenum disulfide sandwiched between an insulator and the electrical conductor graphene on each side. If a voltage is applied to the outer graphene layers it generates an electric field that affects the absorption properties of the two molybdenum disulfide layers. By adjusting the voltage applied wavelengths at which the electron-hole pairs are formed in these […]
Scientists discover new class of semiconducting entropy-stabilized materials
Science Daily July 31, 2020 Almost all entropy-stabilized materials so far are either conducting metals or insulating ceramics. Researchers at the University of Michigan have experimentally synthesized and characterized a new class of the multicationic and -anionic entropy-stabilized chalcogenide alloys based on the (Ge,Sn,Pb)(S,Se,Te) formula. The configurational entropy from the disorder of both the anion and the cation sublattices reaches a record value for the equimolar composition and stabilizes the single-phase solid solution. Theoretical calculations and experiments both show that the synthesized alloys are thermodynamically stable at the growth temperature and kinetically metastable at room temperature. Doping and electronic transport […]
New fabric could help keep you cool in the summer, even without A/C
Science Daily July 29, 2020 When interspersed in fabric the thermally conductive boron nitride has the ability to transfer heat, allow moisture to evaporate from the skin and repel water. To improve the process researchers in China enabled boron nitride to better interpenetrate and remain porous. According to the researchers the material has improved thermal conductivity, moisture permeability, and better resistance to water penetrability and repellency…read more. TECHNICAL ARTICLE
Self-healing soft material outsmarts nature
Nanowerk July 27, 2020 Current self-healing materials have shortcomings such as low healing strength and long healing times limit their practical application. An international team of researchers (USA – State University of Pennsylvania, Germany, Turkey) studied the molecular structure and amino acid sequences of squid proteins and developed a new stretchable biosynthetic material using protein engineering. The squid takes longer to heal because the molecular structure of the proteins inside its tentacles is not perfectly intertwined. With the laboratory-developed squid-inspired material, the scientists changed the nanostructure of the molecules until they created crosslinks between all of them in such a […]
Shells and grapefruits inspire first manufactured non-cuttable material
Science Daily July 20, 2020 An international team of researchers (UK, Germany) has created a bio-inspired metallic cellular structure (with an internal grid of large ceramic segments). It is non-cuttable by an angle grinder and a power drill, and it has only 15% steel density. The architecture derives its extreme hardness from the local resonance between the embedded ceramics in a flexible cellular matrix and the attacking tool, which produces high-frequency vibrations at the interface. The contrast between the ceramic segments and cellular material was also effective against a waterjet cutter because the convex geometry of the ceramic spheres. Shifting […]
‘Blinking’ nanocrystals may convert CO2 into fuels
Nanowerk July 16, 2020 Using polymer‐derived mesoporous carbon (PDMC) as a template, an international team of researchers (USA- State University of New Jersey, China, Czech Republic) has synthesized mesoporous titanium dioxide comprised of small, crystalline, vacancy‐rich anatase nanoparticles that show unique optical, thermal, and electronic properties. When exposed to a slow electron beam, the nanoparticles exhibit a charge/discharge behavior, lighting up and fading away for an average period of 15 s. They show a 50 nm red‐shift in their UV/Vis absorption and long‐lived charge carriers at room temperature in the dark, even long after UV irradiation. As photocatalysts they show […]
Physics team observes extremely fast electronic changes in real time in a special material class
Phys.org July 7, 2020 Topologically protected Weyl semimetal phase in the transition metal dichalcogenide Td-WTe2 can be controlled and, ultimately, destroyed upon the coherent excitation of an interlayer shear mode. An international team of researchers (Germany, China) provide direct experimental evidence that the shear mode acts on the electronic states near the phase-defining Weyl points. They observed a periodic reduction in the spin splitting of bands. Comparison with higher-frequency coherent phonon modes finally proved the shear mode-selectivity of the observed changes in the electronic structure. findings reveal direct experimental insights into electronic processes that are of vital importance for a […]
Multifunctional nanofiber protects against explosions, extreme temps
Science Daily June 29, 2020 Current protection against both thermal and ballistic threats is a combination of multiple high-performance materials that increases equipment weight and complexity. Using para-aramid polymers as the building block researchers at Harvard University engineered precursor solutions to be fluid-like during fiber spinning and solid-like during fiber formation. This allowed for the fabrication of porous, continuous para-aramid fiber sheets (pAFS). Although exhibiting moderately reduced single-fiber mechanics, these pAFS had fragment projectile resistance comparable with commercial para-aramids, while providing 20-fold heat-insulation capability. With these synergistic properties, the nanofiber sheets act as a multifunctional material that can provide improved simultaneous protection…read more. Open […]