Science Daily February 21, 2022 Unlike hydrogel ionic liquids don’t evaporate like water, they are electrically and thermally stable and conduct electricity well, raising interesting opportunities for future applications. An international team of researchers (USA – North Carolina State University, University Nebraska, Australia) has developed a simple one step method for making ionogel. They copolymerized monomers of polyacrylic acid in a solution of ionic liquid using ultraviolet light resulting in a copolymer that incorporates both monomers and the ionic liquid itself. The resulting gel has the stretchability of polyacrylic acid, stronger than the polyacrylamide, and better than cartilage in toughness. […]
Category Archives: Advanced materials
New plant-derived composite is tough as bone and hard as aluminum
MIT News February 10, 2022 So far researchers have been able to incorporate low fractions of the exceptionally strong carbon nanocrystals (CNCs), as the crystals tend to clump and only weakly bond with polymer molecules. To develop a composite with a high fraction of CNCs researcher at MIT determined the ratio of CNC and polymer that would turn the solution into a gel, with a consistency that could either be fed through the nozzle of a 3-D printer or poured into a mold to be cast. When dried the material shrank, leaving behind a solid composite composed mainly of cellulose […]
Super-elastic high-entropy Elinvar alloy discovered with potential for aerospace engineering
EurekAlert February 9, 2022 An international team of researchers (Hong Kong, China, USA- Argonne National Laboratory, France) has discovered a high-entropy alloy called Co25Ni25(HfTiZr)50, (high-entropy Elinvar alloy) reveals the Elinvar effect, that is the alloy firmly retains its elastic modulus over a very wide range of temperature changes. It becomes slightly stiffer than, it is at room temperature, and it expands without any notable phase transition. The experiment verified that the microstructure and mechanical properties of the alloy were insensitive to annealing at 1,273 K (1,000 °C) for different time durations. Because of the combination of the unique structural features, […]
Engineering a multi-element atomic arrangement
Phys.org February 1, 2022 Nano-multi-principal element intermetallic (MPEI) compounds composed of multi-elemental metals in definite proportions have properties and crystal structure that are different from its constituents. An international team of researchers (USA – University of Maryland, Brookhaven National Laboratory, University of Delaware, Oak Ridge National Laboratory, Argonne National Laboratory, Washington State University, UC San Diego, Canada) has demonstrated a disorder-to-order phase transition approach that enabled the synthesis of ultrasmall and stable MPEI nanoparticles (up to eight elements). They applied 5 min of Joule heating to promote the phase transition of the nanoparticles into L10 intermetallic structure, which is then […]
Nano-architected material refracts light backward – an important step toward one day creating photonic circuits
Nanowerk January 28, 2022 Negative refraction has not been observed in nature but was theorized to occur in artificially periodic materials. Researchers at Caltech designed, fabricated 3D photonic crystals (PhCs) capable of negative refraction in the mid-infrared. Band structure and equifrequency contours were calculated to inform the design of 3D polymer–germanium core–shell PhCs. They successfully characterized a polymer–Ge core–shell lattice and mapped its band structure, which were used to calculate the PhC refraction behavior. An analysis of wave propagation revealed that this 3D core–shell PhC refracts light negatively and possesses an effective negative index of refraction in the experimentally observed […]
A nanoscale 3D structure to control light
Phys.org February 2, 2022 Metamaterials can be engineered to produce desired interactions with light or sound waves. However, functionality of the devices can be limited by the corresponding design space. A team of researchers in the US (Pennsylvania State University, Sandia National Laboratory) leveraged a combination of a genetic algorithm (GA) based optimization method and a membrane projection lithography (MPL) fabrication approach, to demonstrate a quasi-3D metamaterial for broadband asymmetric transmission (AT) of linearly polarized mid-infrared light. An efficient exploration of 3D plasmonic meta-atoms with broken mirror symmetry in the light propagation direction allows the satisfaction of the rigorous conditions […]
New p-type, near-infrared transparent conducting thin films with better performance
Phys.org January 19, 2022 The low conductivity of previous CuMO2 films obstructs the development of delafossite-based electronics. Researchers in China designed and fabricated a new p-type 4d transition metal Rh-based CuRhO2 film by a facile solution method. It has room-temperature conductivity as high as 735 S cm−1 which was achieved by substituting 10%Mg in Rh sites. The acceptor-doped CuRhO2 films exhibited high near-infrared transmittance of 85–60% with low room-temperature sheet resistance of 4.28–0.18 kΩ sq−1. The electronic structure, electrical transport mechanism, and intra-band excitation feature for the CuRhO2 film are unveiled. According to the researchers theoretical and experimental results contribute […]
Engineers develop the first anti-COVID-19 stainless steel
Phys.org December 9, 2021 SARS-CoV-2 exhibits strong stability on conventional stainless steel (SS) surface, with infectious virus detected even after two days. Researchers in Hong Kong investigated the stabilities of SARS-CoV-2, H1N1 influenza A virus (H1N1), and Escherichia coli (E.coli) on the surfaces of Cu-contained (SS), pure Cu, Ag-contained SS, and pure Ag. They found that pure Ag and Ag-contained SS surfaces do not display apparent inhibitory effects on SARS-CoV-2 and H1N1. In comparison, both pure Cu and Cu-contained SS with a high Cu content exhibit significant antiviral properties. Anti-pathogen SS with 20 wt% Cu can distinctly reduce 99.75% and […]
Liquid crystals for fast switching devices
Phys.org December 6, 2021 In some liquid crystals the molecules self-assemble into helical structures which are characterized by pitch. Pitch determines how quickly they react to an applied electric field. An international team of researchers (Germany, Czech Republic, Russia) investigated a liquid crystalline cholesteric compound called EZL10/10 which had only one chiral center and it was only104 nanometres. Further analysis showed that in this material the cholesteric spirals form domains with characteristic lengths of about five pitches. According to the researchers the short pitch makes the material unique and promising for optoelectronic devices with very fast switching times, and the […]
Polymer that folds and unfolds under UV radiation
Phys.com November 30, 2021 An international team of researchers (Japan, Switzerland, UK) built the supramolecular polymer from monomers that formed six-membered rosettes stacked on top of one another to give an infinitely long chain. An intrinsic curvature generated along the stacked rosettes caused the nanofibers to twist up and fold into a helical structure. The folding could be removed by triggering a “light switch”. UV-light irradiation caused the monomer to bend, forming a kink in the molecule, reducing the rotation of the rosette, and unfolding the helical structure. A second switch which works using temperature prevented the entire polymer from […]