Science Daily March 30, 2018 Previously engineered ultradrawn nanofibers from a standard sample of polyethylene could only dissipate heat along the length of each polymer chain. A team of researchers in the US (MIT, Argonne National Laboratory) developed a new way to engineer a polymer conductor using oxidative chemical vapor deposition, whereby two vapors are directed into a chamber and onto a substrate, where they interact and form a film creating rigid chains of polymers, rather than the twisted, spaghetti-like strands in normal polymers. 2 square centimeter samples they produced were able to conduct heat at about 2 watts per […]
Category Archives: Advanced materials
Knitting electronics with yarn batteries
Science Daily March 28, 2018 Researchers in China twisted carbon nanotube fibers into a yarn, then coated one piece of yarn with zinc to form an anode, and another with magnesium oxide to form a cathode. These two pieces were then twisted like a double helix and coated with a polyacrylamide electrolyte and encased in silicone. In tests the yarn zinc-ion battery was stable, had a high charge capacity, was rechargeable and waterproof. The material could be knitted and stretched, cut into several pieces, each of which could power a watch. In a proof-of-concept demonstration, eight pieces of the cut […]
Microengineered slippery rough surface for water harvesting in air
Nanowerk March 30, 2018 A team of researchers in the US (Pennsylvania State University, UT Dallas) developed a pitcher plant-inspired slippery surface with hydrophilic chemistry. They added the directional grooves and gave the new surface a microscale roughness that increased the surface area. The rate of water and fog harvesting are directly proportional to the amount of surface area on which droplets can form. The rice leaves-inspired grooves whisk the water droplets away through capillary action or gravity. If the slippery rough surface (SRS) material is produced at scale, they estimate that over 120 liters of water can be collected […]
Tuning in to magnetic ink
Eurekalert April 4, 2018 By injecting iron-based reagents into a hot acetic acid solution, researchers in Saudi Arabia synthesized magnetic iron-oxide nanoparticles that dispersed into deionized water to form an ink. When deposited as a thin film on a glass substrate, the new magnetic substrate could act as an energy-storing inductor device with an adjustable capacity of over 20 percent. By modifying the nanoparticles’ surfaces with hydrocarbon chains, they were able to produce free-standing magnetic sheets of a few millimeters in thickness. The discovery boosts prospects for inexpensive electronics that work worldwide by tuning in to multiple cellular bands and […]
Modified biomaterials self-assemble on temperature cues
Phys.org March 19, 2018 Post-translational modification of proteins is a strategy widely used in biological systems which has remained largely untapped for the synthesis of biomaterials. As a proof of concept of this technique, an international team of researchers (USA – Duke University, Germany) reports the generation of a family of three stimulus-responsive hybrid materials—fatty-acid-modified elastin-like polypeptides—using a one-pot recombinant expression and post-translational lipidation methodology. The hybrid approach allows researchers to control self-assembly more precisely, which may prove useful for a variety of biomedical applications from drug delivery to wound healing… read more. TECHNICAL ARTICLE
The quantum states on the surface of conducting materials can strongly interact with light
Physorg March 9, 2018 Researchers in Singapore show that Dirac semimetals are unusual in that they possess a very optically active surface due to the peculiar Fermi arc states. Surface absorption depends heavily on the polarization of light, being 100 to 1,000 times stronger when light is polarized perpendicular—rather than parallel—to the crystal’s rotational axis. This strong anisotropy offers a way of optically investigating and probing the topological surfaces states of Dirac semimetals which could host unusual opto-electronic behavior that goes beyond conventional materials… read more. TECHNICAL ARTICLE
Research team creates hydrogel adhesives to seal wounds
Physorg March 9, 2018 Researchers at Harvard University have developed a hydrogel which is a hybrid of two different polymers: a seaweed extract called alginate and polyacrylamide. When these become entangled with each other, they create a molecular network that demonstrates unprecedented toughness and resilience for a hydrogel material—on par with the body’s natural cartilage. When combined with an adhesive layer containing positively charged polymer molecules, the resulting hybrid material can bind to tissues, stretch up to 20 times its initial length, and attach to wet tissue surfaces undergoing dynamic movement… read more.
A treasure trove for nanotechnology experts
Eurekalert March 6, 2018 Starting from 108,423 unique, experimentally known 3D compounds, an international team of researchers (Switzerland, Lithuania) has identified a subset of 5,619 compounds that appear layered according to robust geometric and bonding criteria. Out of those 1,825 compounds are either easily or potentially exfoliable. For a subset of 258 compounds, they explored vibrational, electronic, magnetic and topological properties, identifying 56 ferromagnetic and antiferromagnetic systems, including half-metals and half-semiconductors. The research paves the way for groundbreaking technological applications… read more. TECHNICAL ARTICLE
When rotated at a ‘magic angle,’ graphene sheets can form an insulator or a superconductor
Physorg March 5, 2018 An international team of researchers (USA – MIT, Harvard University, Japan) created a “superlattice” of two graphene sheets stacked together at a “magic angle” of 1.1 degrees creating a precise moiré configuration. They found that at the magic angle, the two sheets of graphene exhibit nonconducting behavior similar to Mott insulators. When they applied voltage by adding small amounts of electrons to the graphene superlattice, at a certain level, the electrons broke out of the initial insulating state and flowed without resistance, as if through a superconductor. The finding provides a platform for investigating unconventional superconductivity, […]
New graphene laser technique opens door for edible electronics
Eurekalert February 28, 2018 An international team of researchers (USA – Rice University, Israel) reports a method of using multiple pulsed-laser scribing to convert a wide range of substrates into laser-induced graphene (LIG). With the increased versatility of the multiple lase process, highly conductive patterns can be achieved on the surface of a diverse number of substrates in ambient atmosphere. The use of a defocus method results in multiple lases in a single pass of the laser, further simplifying the procedure. Any carbon precursor that can be converted into amorphous carbon can be converted into graphene using this multiple lase […]