Science Daily June 22, 2020 Researchers at Northwestern University have developed hybrid light-responsive soft materials composed of peptide amphiphile supramolecular polymers chemically bonded to spiropyran-based networks that expel water in response to visible light. The supramolecular polymers form a reversibly deformable and water-draining skeleton that mechanically reinforces the hybrid and can also be aligned by printing methods. The noncovalent skeleton embedded in the network enables faster bending and flattening actuation of objects, as well as longer steps during the light-driven crawling motion of macroscopic films. As the material can be designed in different shapes, it could play a role in […]
Category Archives: Advanced materials
A ‘hole’ lot of sponge! New technique to create super-sponges is a game changer
EurekAlert June 10, 2020 Unlike traditional porous materials, in theory MOFs structure can be controlled through careful selection of the components of the synthesis process. But in practice, this process is challenged by the restricted synthetic conditions and high thermal and chemical sensitivity of MOFs. Researchers in South Korea introduced stable carbon-carbon bonds by converting existing carbon-hydrogen bonds using elevated temperatures and adding “electrophilic organic halides or carbonyl compounds”, allowing simultaneous introduction of the required functional groups as well as the mesoscopic holes. This technique could potentially improve the safety of workers in enclosed, gas-filled environments such as in the […]
Scientists develop the most heat-resistant material ever created
Phys.org May 27, 2020 Using the method of self-propagating high-temperature synthesis, an international team of researchers (Russia, USA – University of Notre Dame) fabricated nonstoichiometric hafnium carbonitrides (HfCxNy). It had a rock-salt crystal structure with a lattice parameter of 0.4606 nm. and hardness of 21.3 GPa. The melting point of this synthesized material was experimentally shown to be higher than that of binary hafnium carbide. The nonstoichiometric hafnium carbonitride was then consolidated under a constant pressure of 50 MPa at a temperature of 2000 °C and a dwelling time of 10 min, through spark plasma sintering. The obtained bulk ceramic […]
Untwisting plastics for charging Internet-of-things devices
Nanowerk May 27, 2020 To use body heat to charge some types of micro-devices and sensors requires lightweight, non-toxic, wearable, and flexible thermoelectric generators. Researchers in Japan studied the thermoelectric properties of a highly conductive thiophene-based polymer, called PBTTT. They found that doping the polymer with a thin ion electrolyte gel improves conductivity and infiltrates the polymer successfully when a specific electric voltage is applied. Doping it with a critical amount of electrolyte untwists the highly twisted chain and creates links between its crystalline parts, improving electron conductivity. They are now looking into ways to optimize the thermoelectric performance of […]
Making quantum ‘waves’ in ultrathin materials
EurekAlert May 14, 2020 To understand how plasmons operate in quasi 2D crystals an international team of researchers (USA – UC Berkeley, Lawrence Berkeley National Laboratory, research organization, Germany) characterized the properties of both nonconductive and conductive electrons in a monolayer of the TMD tantalum disulfide. Using the new algorithms they developed to compute the material’s electronic properties, they found the plasmons in quasi 2D TMDs are much more stable – for as long as approximately 2 picoseconds than previously thought. Their findings also suggest that plasmons generated by quasi 2D TMDs could enhance the intensity of light by more […]
Breathable second skin materials provide smart protection against chemical and biological agents
Nanowerk May 6, 2020A team of researchers in the US (Lawrence Livermore National Laboratory, U.S. Army Natick Soldier Research, Development and Engineering Center, MA) demonstrated a smart material that is both breathable and protective by successfully combining a base membrane layer comprising trillions of aligned carbon nanotube pores and a threat-responsive polymer layer grafted onto the membrane surface. The carbon nanotubes could easily transport water molecules through their interiors while also blocking all biological threats, which cannot fit through the tiny pores. To add protection against chemical hazards, a layer of polymer chains is grown on the material surface, which […]
Researchers pave the way to designing omnidirectional invisible materials
EurekAlert May 7, 2020 Researchers in Spain have demonstrated that Maxwell’s equations, as well as the acoustic and elastic wave equations, also possess an underlying supersymmetry in the time domain. They explored the consequences of this property in the field of optics, obtaining a simple analytic relation between the scattering coefficients of numerous time-varying systems, and uncovering a wide class of reflectionless, three dimensional, all-dielectric, isotropic, omnidirectional, polarisation-independent, non-complex media. These unprecedented features may enable the creation of novel reconfigurable devices, including invisible materials, frequency shifters, isolators, and pulse-shape transformers…read more. Open Access TECHNICAL ARTICLE
Shape-shifting carbon fibre could replace mechanical systems for planes and more
Nanowerk May 7, 2020 Researchers in Sweden have developed a material that is manufactured from commercial carbon fibers and a structural battery electrolyte and uses lithium-ion insertion to produce shape changes at low voltages. It is an electrically controlled solid-state morphing composite material that is lightweight and has a stiffness higher than aluminum. It is capable of producing large deformations and holding them with no additional power, albeit at low rates. A proof-of-concept material in a cantilever setup was used to show morphing. Analytical modeling showed good correlation with experimental observations. The concept presented shows considerable promise and paves the […]
Electrical manipulation of magnetic particle allows for large high-speed memory
Phys.org April 20, 2020 Antiferromagnetic materials seem harder to work with but have many useful properties and they are less subject to external magnetic fields due to a unique arrangement of their constituent parts making it harder to manipulate the material as needed. According to researchers in Japan in antiferromagnetic manganese-tin alloy Mn3Sn Weyl fermions exist at Weyl points in momentum space. They have two possible states that could represent binary digits. They found that it is possible to switch a Weyl point between these states with an external electrical current applied to neighboring thin layers of Mn3Sn and either […]
Carbon nanostructure created that is stronger than diamonds
Science Daily April 13, 2020 An international team of researchers (USA – UC Irvine, UC Santa Barbara, industry, Germany) has succeeded in conceptualizing and fabricating the material which consists of closely connected closed-cell plates instead of the cylindrical trusses common in such structures over the past few decades. They have shown that the design improves the average performance of cylindrical beam-based architectures by up to 639 percent in strength and 522 percent in rigidity. One of the group’s innovations was to include tiny holes in the plates that could be used to remove excess resin from the finished material…read more. […]