Physics World April 11, 2020 Techniques for manufacturing graphite films take several hours and require processing temperatures of around 3000°C. Researchers in China produced high-quality graphite film tens of nanometres thick within a few seconds by heating nickel foil to 1200°C in an argon atmosphere and then rapidly immersing this foil in ethanol at 0°C. The carbon atoms produced from the decomposition of ethanol diffuse and dissolve into the nickel because of its high carbon solubility. As this carbon solubility greatly decreases at low temperature, the carbon atoms subsequently segregate and precipitate from the nickel surface during quenching, producing a […]
Tag Archives: Advanced materials
World’s most complex microparticle: A synthetic that outdoes nature’s intricacy
Nanowerk April 10, 2020 The structural complexity of composite biomaterials and biomineralized particles arises from the hierarchical ordering of inorganic building blocks over multiple scales. An international team of researchers (USA – University of Michigan, Caltech, University of Pennsylvania, Brazil) assembled hierarchically organized particles (HOPs) with twisted spikes and other morphologies from polydisperse Au-Cyc nanoplatelets. Its complexity is higher than biological counterparts or other complex particles. Their intricate organization emerges from competing chirality-dependent assembly restrictions that render assembly pathways primarily dependent on nanoparticle symmetry rather than size. The researchers believe that the tactics they have uncovered can help scientists engineer […]
Engineers use metal-oxide nanomaterials deposited on cloth to wipe out microbes
Nanowerk April 8, 2020 As proof of concept researchers at the State University of Iowa grew shape-controlled cerium oxide nanostructures on fluorine doped tin oxide, carbon paper, and carbon cloth as substrates. They found that the cerium oxide nanostructures grown directly on carbon cloth were the most sensitive glucose biosensors. The enhanced performance of these biosensors was related to the increased surface area and high defect concentrations on the surface. These results provide a potential opportunity for flexible substrates like carbon paper and carbon cloth coupled with nanostructures, in a feasible design, to be used as platforms for robust, affordable, […]
Graphene-based actuator swarm enables programmable deformation
Nanowerk April 1, 2020 Graphene-based actuators featuring fast and reversible deformation under various external stimuli are promising for soft robotics. However, these bimorph actuators are incapable of complex and programmable 3D deformation, which limits their practical application. Researchers in China fabricated a moisture-responsive graphene actuator swarm that has programmable shape-changing capability by programming the SU-8 patterns underneath with specific geometries and orientations on a continuous graphene oxide film, forming a swarm of bimorph actuators. They achieved predictable and complex deformations including bending, twisting, coiling, asymmetric bending, 3D folding and the combination of them due to the collective coupling and coordination […]
Creating stretchable thermoelectric generators
Science Daily March 24, 2020 An international team of researchers (Sweden, USA – California Polytechnic University, New Zealand, Belgium) combined three materials: the conducting polymer PEDOT:PSS, a water-soluble polyurethane rubber, and an ionic liquid resulting in a composite with unique properties. The PEDOT:PSS gives it thermoelectric properties – the rubber provides elasticity, and the ionic liquid ensures softness. The material is 100 times softer and 100 times more stretchable than PEDOT:PSS. It can be printed onto various surfaces. When the surface flexes or folds, the composite follows the motion. The process to manufacture the composite is cheap and environmentally friendly. […]
To make ultra-black materials that won’t weigh things down, consider the butterfly
Science Daily March 10, 2020 Recently, it has been shown that animals such as jumping spiders, birds, and butterflies have evolved ultra-black coloration comparable to the blackest synthetic materials. Researchers at Duke University examined a phylogenetically diverse set of butterflies and found considerable interspecific variation in the geometry of the holes in the structures reduce reflectance up to 16-fold. They produce ultra-black by creating a sparse material with high surface area to increase absorption and minimize surface reflection. They hypothesized that butterflies use ultra-black to increase the contrast of color signals. The findings could help engineers design thinner ultra-black coatings […]
Manipulating atoms to make better superconductors
Science Daily March 3, 2020 The creation of collective behavior is the fundamental building block from which superconductivity emerges. A team of researchers in the US (University of Illinois at Chicago, SLAC National Accelerator Laboratory, Stanford University) had theoretically predicted in a Kondo droplet, for certain distances between the cobalt atoms, the nanoscopic system should start to exhibit collective behavior, while for other distances, it should not. They confirmed the predictions by experiments that showed that collective behavior appears in Kondo droplets containing as little as 37 cobalt atoms. It allows us to move one step closer to developing the […]
Researchers identify breaking point of conducting material
EurekAlert March 4, 2020 Accurate predictions of the temperature when embrittlement occurs is crucial to design conducting polymers that are used in next-generation flexible electronics. An international team of researchers (USA – Pennsylvania State University, Germany) found a way to measure glass transition temperatures by keeping track of the mechanical properties as embrittlement occurs, laying the foundation for understanding the relationship between the glass transition and structure. Follow-up studies then determined the glass transition for 32 different polymers by measuring mechanical properties as a function of temperature. They showed the simple relationship between the chemical structure and the glass transition […]
Scientists created an ‘impossible’ superconducting compound
Phys.org March 3, 2020 An international team of researchers (China, Russia) successfully synthesized praseodymium superhydrides (PrHg) and showed the emergence of a possible superconducting transition (Tc) below 9 K and Tc dependent on the applied magnetic field. Theoretical calculations indicated that magnetic order and likely superconductivity coexist in a narrow range of pressures in the PrHg sample, which may contribute to its low superconducting temperature. The results highlight the intimate connections between hydrogenic sublattices, density of states, magnetism, and superconductivity in Pr-based superhydrides…read more. Open Access TECHNICAL ARTICLE
This wearable device camouflages its wearer no matter the weather
Phys.org March 3, 2020 An international team of researchers (USA -UC San Diego, Singapore) has developed a proof-of-concept device that has a surface that cools down or heats up to match ambient temperatures, camouflaging the wearer’s body heat. The surface can go from 10 to 38 degrees Celsius (50 to 100.5 degrees Fahrenheit) in less than a minute. They used phase-changing material that’s like wax but with more complex properties. The melting point of the material is 30 degrees Celsius (roughly 86 degrees F), the same temperature as the surface temperature of human skin. The outside layer of the device […]