Material Science News and Discussions

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Entirely new form of carbon follows the lead of graphene
By Nick Lavars
May 20, 2021

Researchers in Europe have developed an entirely new form of carbon, one that bears similarities to the wonder material graphene but with some useful differences. The incredibly thin sheets of material offer some electrical properties that other forms of carbon do not, which could open up new possibilities around electronics and advanced lithium batteries.

Graphene has generated a lot of hype in material science circles due to its incredible strength, flexibility, thinness and lightness, along with its ability to act as an excellent conductor of heat and electricity. As a two-dimensional sheet of carbon, it owes these characteristics to its unique arrangement of atoms that are organized in a honeycomb pattern, and scientists have suspected that alternative arrangements could give other two-dimensional forms of carbon their own unique qualities.

https://newatlas.com/materials/new-form ... -graphene/

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New optimization approach helps design lighter carbon fiber composite materials

by Tokyo University of Science

Researchers from Tokyo University of Science adopt a design approach for carbon fibers that optimizes fiber orientation and thickness to enhance the strength of fiber reinforced plastic, producing lighter plastic in the process that can help build lighter airplanes and automobiles. Credit: Robert Bye on Unsplash

Carbon is vital to the existence of all living organisms, since it forms the basis of all organic molecules that, in turn, form the basis of all living beings. While that alone is pretty impressive, it has recently found surprisingly novel applications in disciplines such as aerospace and civil engineering with the development of carbon fibers that are stronger, stiffer, and lighter than steel. Consequently, carbon fibers have taken over steel in high-performance products like aircrafts, racecars, and sports equipment.

https://phys.org/news/2021-05-optimizat ... fiber.html

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New form of silicon could enable next-gen electronic and energy devices
https://phys.org/news/2021-06-silicon-e ... nergy.html
by Carnegie Institution for Science

A team led by Carnegie's Thomas Shiell and Timothy Strobel developed a new method for synthesizing a novel crystalline form of silicon with a hexagonal structure that could potentially be used to create next-generation electronic and energy devices with enhanced properties that exceed those of the "normal" cubic form of silicon used today.

Their work is published in Physical Review Letters.

Silicon plays an outsized role in human life. It is the second most abundant element in the Earth's crust. When mixed with other elements, it is essential for many construction and infrastructure projects. And in pure elemental form, it is crucial enough to computing that the longstanding technological hub of the U.S.—California's Silicon Valley—was nicknamed in honor of it.

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Machine learning speeds up simulations in material science
https://phys.org/news/2021-06-machine-s ... ience.html
by Karlsruhe Institute of Technology

Research, development, and production of novel materials depend heavily on the availability of fast and at the same time accurate simulation methods. Machine learning, in which artificial intelligence (AI) autonomously acquires and applies new knowledge, will soon enable researchers to develop complex material systems in a purely virtual environment. How does this work, and which applications will benefit? In an article published in the Nature Materials journal, a researcher from Karlsruhe Institute of Technology (KIT) and his colleagues from Göttingen and Toronto explain it all.

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New method makes generic polymers luminescent
https://phys.org/news/2021-06-method-po ... scent.html
by Hokkaido University

Researchers from Hokkaido University have successfully developed a new method to give luminescent properties to generic polymers, such as polystyrene and polyethylene. The technique, which was published in the journal Angewandte Chemie International Edition, makes it possible to easily prepare luminescent polymers without using complicated organic synthetic methods.

"Luminescent polymers are widely used in modern society, in applications such as organic lasers, solar cells, sensors and bioimaging, but their preparation often requires multiple chemical synthesis steps, which are both time and labor intensive," explains Professor Hajime Ito, one of the authors of the study and Vice Director of the Institute for Chemical Reaction Design and Discovery (WPI-ICReDD) at Hokkaido University.

To overcome this problem, the research team investigated whether luminescent polymers could be prepared using mechanical force as opposed to sophisticated chemical synthesis.

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Scientists create concrete replacement from food leftovers
https://cbsaustin.com/news/offbeat/scie ... -leftovers
by GRAINGER LAFFAN, Zenger NewsFriday, June 11th 2021

TOKYO (Zenger News) — Those stubborn lumps you struggle to scrape off last night’s dinner plates are inspiring scientists to make new ultra-strong building materials.

Researchers in Japan have created a concrete replacement out of food scraps — and the new compound can be both edible and sweet-smelling.

Associate professor Yuya Sakai at the Institute for Industrial Science at the University of Tokyo and Kota Machida, whose research was part of his graduate studies at the university, spoke about the inspiration behind using food waste for construction.

Food waste amounts to billions of pounds per year, they said, and the cost to the environment is immense. It made sense to test these raw products to see if they could make construction materials with compatible or better strength than concrete.

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Extraordinary new material shows zero heat expansion from 4 to 1,400 K
By Loz Blain
June 11, 2021
https://newatlas.com/materials/thermall ... -material/

Australian researchers have created what may be one of the most thermally stable materials ever discovered. This new zero thermal expansion (ZTE) material made of scandium, aluminum, tungsten and oxygen did not change in volume at temperatures ranging from 4 to 1400 Kelvin (-269 to 1126 °C, -452 to 2059 °F).

That's a wider range of temperatures, say scientists from the University of New South Wales (UNSW), than any other material demonstrated to date, and it could make orthorhombic Sc1.5Al0.5W3O12 (catchy name, eh?) a very handy tool for anyone engineering something that needs to work in extremely varied thermal environments.

Examples of where this might come in handy include things like aerospace design, where components are exposed to extreme cold in space and extreme heat at launch or on re-entry. Famously, the SR-71 Blackbird was designed to expand so much at its Mach 3.4 top speed that it would liberally drizzle fuel on the runway at ground temperatures; the fuel tanks wouldn't even fully seal until they heated up. This new material stays exactly the same volume from close to absolute zero all the way up to comfortably over the heat you'd expect to get on the wing of a hypersonic aircraft traveling at Mach 5.

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Self-healing concrete eats CO2 to fill its own cracks in 24 hours
By Nick Lavars
June 14, 2021

Concrete has a massive carbon footprint, so technologies that boost its performance and enable it to last longer could have profound benefits for the environment. This has led to the development of self-healing concrete that can repair its own cracks, and scientists have now demonstrated an exciting new form of this that makes use of an enzyme found in human blood.

Tiny cracks that form in concrete mightn't pose an immediate problem to the structural integrity of a construction, but as water gets in and the rupture spreads it can greatly compromise its strength. The idea with self-healing concrete is to intervene in this process while the cracks are still tiny, sealing up the material to prevent not just a catastrophic collapse, but expensive maintenance or a complete replacement of the structure.

This field of research has turned up all kinds of interesting potential solutions over the years. We've seen versions that pack their own sodium silicate healing agents, ones that feature bacteria that produce special glue to knit together these cracks, and others that fill up the gaps with fungus. While promising, scientists at the Worcester Polytechnic Institute have conjured up what they believe is a cheaper and even more efficient solution.

https://newatlas.com/materials/self-hea ... od-enzyme/

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New material could remove respiratory droplets from air

by Northwestern University
https://phys.org/news/2021-06-material- ... s-air.html

Although plexiglass barriers are seemingly everywhere these days—between grocery store lanes, around restaurant tables and towering above office cubicles—they are an imperfect solution to blocking virus transmission.

Instead of capturing virus-laden respiratory droplets and aerosols, plexiglass dividers merely deflect droplets, causing them to bounce away but remain in the air. To enhance the function of these protective barriers, Northwestern University researchers have developed a new transparent material that can capture droplets and aerosols, effectively removing them from air.

The material is a clear, viscous liquid that can be painted onto any surface, including plastic, glass, wood, metal, stainless steel, concrete and textiles. When droplets collide with the coated surface, they stick to it, get absorbed and dry up. The coating also is compatible with antiviral and antimicrobial materials, so sanitizing agents, such as copper, could be added to the formula.

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World’s lightest sound insulator could radically reduce jet engine noise
By Loz Blain
June 17, 2021
https://newatlas.com/materials/ultralig ... on-aerogel

This graphene-based aerogel is the lightest sound insulation material ever manufactured, say researchers at the University of Bath, who have demonstrated its ability to damp down noise by up to 16 decibels despite weighing just 2.1 kg per cubic meter (0.13 lb per cubic foot).

You might not think weight is that much of a factor with acoustic foams, but to put this aerogel's density in context, compare it to a conventional polyester urethane sound absorber like Kinetics KUA, which was "developed to absorb maximum acoustical energy using minimum weight and thickness" with a density of 32 kg/m3 (2 lb/ft3). So in a given application, this new "graphene oxide-polyvinyl alcohol aerogel," squeezed into a Nomex honeycomb, would weigh less than one-fifteenth of an equivalent traditional acoustic foam installation.

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Engineers develop inexpensive, scalable method to make metamaterials that manipulate microwave energy

by Tufts University
https://techxplore.com/news/2021-06-ine ... owave.html

Engineers at Tufts University have developed new methods to more efficiently fabricate materials that behave in unusual ways when interacting with microwave energy, with potential implications for telecommunications, GPS, radar, mobile devices, and medical devices. Known as metamaterials, they are sometimes referred to as "impossible materials" because they could, in theory, bend energy around objects to make them appear invisible, concentrate the transmission of energy into focused beams, or have chameleon like abilities to reconfigure their absorption or transmission of different frequency ranges.

The innovation, described today in Nature Electronics, constructs the metamaterials using low-cost inkjet printing, making the method widely accessible and scalable while also providing benefits such as the ability to be applied to large conformable surfaces or interface with a biological environment. It is also the first demonstration that organic polymers can be used to electrically "tune" the properties of the metamaterials.

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Tougher Than Kevlar and Steel: Ultralight Material Withstands Supersonic Microparticle Impacts

The new carbon-based material could be a basis for lighter, tougher alternatives to Kevlar and steel.

A new study by engineers at MIT, Caltech, and ETH Zürich shows that “nanoarchitected” materials — materials designed from precisely patterned nanoscale structures — may be a promising route to lightweight armor, protective coatings, blast shields, and other impact-resistant materials.

The researchers have fabricated an ultralight material made from nanometer-scale carbon struts that give the material toughness and mechanical robustness. The team tested the material’s resilience by shooting it with microparticles at supersonic speeds, and found that the material, which is thinner than the width of a human hair, prevented the miniature projectiles from tearing through it.

The researchers calculate that compared with steel, Kevlar, aluminum, and other impact-resistant materials of comparable weight, the new material is more efficient at absorbing impacts.

“The same amount of mass of our material would be much more efficient at stopping a projectile than the same amount of mass of Kevlar,” says the study’s lead author, Carlos Portela, assistant professor of mechanical engineering at MIT.

Engineers at MIT, Caltech, and ETH Zürich find “nanoarchitected” materials designed from precisely patterned nanoscale structures (pictured) may be a promising route to lightweight armor, protective coatings, blast shields, and other impact-resistant materials. Credit: Courtesy of the researchers

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Research team shows complex, 3D-printed schwarzites withstand pressure when coated
https://phys.org/news/2021-07-team-comp ... ssure.html
by Rice University

A thin shell of soft polymer can help keep knotty ceramic structures from shattering, according to materials scientists at Rice University.

Ceramics made with 3D printers crack under stress like any plate or bowl. But covered in a soft polymer cured under ultraviolet light, the same materials stand a far better chance of keeping their structural integrity, much like a car windshield's treated glass is less likely to shatter.

The research at Rice's Brown School of Engineering, which appears in Science Advances, demonstrates the concept on schwarzites, complex lattices that for decades existed only as theory but can now be made with 3D printers. With added polymers, they come to resemble structures found in nature like seashells and bones that consist of hardened platelets in a biopolymer matrix.

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Solving the plastic shortage with a new chemical catalyst
https://phys.org/news/2021-07-plastic-s ... alyst.html
by University of Michigan

In a year that has already battered manufacturing supply chains, yet another shortage is complicating manufacturers' and consumers' lives: plastics, and the food packaging, automotive components, clothing, medical and lab equipment and countless other items that rely on them.

But a new chemical catalyst developed at the University of Michigan could enable the production of more of the feedstock for the world's second-most widely used plastic. The feedstock, propylene, is used to make the plastic polypropylene—8 million tons of it each year.

The new catalyst, which can make propylene from natural gas, is at least 10 times more efficient than current commercial catalysts. And it lasts 10 times longer before needing regeneration. It is made of platinum and tin nanoparticles that are supported by a framework of silica.

"Industry has shifted over the years from petroleum feedstocks to shale gas," said Suljo Linic, the Martin Lewis Perl Collegiate Professor of Chemical Engineering at U-M and senior author on a paper published in Science. "So there has been a push to find a way to efficiently produce propylene from propane, a component of shale gas. This catalyst achieves that objective."

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3D-printable phase-change materials insulate buildings better at scale
By Michael Irving
July 12, 2021
https://newatlas.com/materials/3d-print ... nsulation/

Heating and cooling systems are some of the biggest energy guzzlers in use, so passive temperature control could be a good way to reduce emissions. Phase-change materials (PCMs) show promise for this, and now engineers at Texas A&M have developed a new PCM composite that can be 3D printed.

The name “phase-change materials” is pretty self-explanatory – these materials will switch between phases of matter as the temperature changes. One of the most promising applications for this technology is insulation: the PCM melts into a liquid as it absorbs heat, cooling its surroundings. As the ambient temperature cools, the material will solidify again, releasing its stored heat.

In the past, PCMs have been used in coffee cups to keep hot drinks hot, fabrics that keep wearers warm or cool as needed, liquid coatings that prevent frost build-up, and in building materials that better regulate indoor temperature. It’s that last one that the researchers on the new study wanted to improve.

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Researchers discover a 'layer hall effect' in a 2D topological Axion antiferromagnet
https://phys.org/news/2021-07-layer-hal ... gical.html
by Boston College

Researchers have discovered a "layer" Hall effect in a solid state chip constructed of antiferromagnetic manganese bismuth telluride, a finding that signals a much sought-after topological Axion insulating state, the team reports in the current edition of the journal Nature.

Researchers have been trying to find evidence of a topological Axion insulating (TAI) state and developed some candidate materials based on theoretical calculations. The layered Hall effect represents the first clear experimental evidence of the state, a feature bound by the laws of quantum physics, according to Boston College Assistant Professor of Physics Qiong Ma, a senior researcher on the project, which included 36 scientists from universities in the U.S., Japan, China, Taiwan, Germany, and India.

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Simple, inexpensive method for guarding carbon fiber
https://phys.org/news/2021-07-simple-in ... fiber.html
by Tiffany Lee, University of Nebraska-Lincoln

For the past 50 years, manufacturers have considered carbon fiber a dream material: Though individual fibers are thinner than a strand of human hair, they can be twisted together and fused with a matrix material to form a lightweight composite that is stronger than steel, twice as stiff and a good conductor of heat. And, unlike metals, the material doesn't crack over time. It's been used in a wide range of applications, including air and spacecraft, cars, buildings, medical devices and sports equipment.

But carbon fiber has a major drawback, said Husker engineer Yongfeng Lu, an expert in carbon materials. Under extreme temperatures—encountered routinely in the aerospace industry, for example—carbon fiber oxidizes, meaning it reacts with oxygen in the air and burns, just as wood does when combined with enough heat and oxygen. Oxidation quickly diminishes the dream-like qualities of carbon fiber, particularly its strength.

"One weakness of carbon fibers is that they are burned easily if you have high enough temperatures and oxygen present," said Lu, Lott Distinguished University Professor of electrical and computer engineering. "If we could make them non-flammable, so that they don't burn when exposed to fire, that would be exciting."

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Through the thin-film glass, researchers spot a new liquid phase
https://phys.org/news/2021-07-thin-film ... phase.html
by University of Pennsylvania

Research published in the Proceedings of the National Academy of Sciences describes a new type of liquid in thin films, which forms a high-density glass. Results generated in this study, conducted by researchers in Penn's Department of Chemistry, demonstrate how these glasses and other similar materials can be fabricated to be denser and more stable, providing a framework for developing new applications and devices through better design.

Glass is typically created through solidification, or falling out of equilibrium, of a liquid when it is cooled to a temperature where its motion arrests. The structure of a glass closely resembles the liquid phase, but its properties are similar to solids, akin to a crystal.

Glasses that are made into ultrathin, nanometer-scale films are widely used in applications such as OLED displays and optical fibers. But when these types of glasses are made into thin films, even at cold temperatures they behave more like a liquid, and the resulting material can be prone to droplet formation or crystallization, which limits the size of the smallest features that are possible.

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Metallic water created for the first time in golden experiment
By Michael Irving
July 28, 2021

https://newatlas.com/science/metallic-water-experiment/
Researchers have created metallic water for the first time. Through a very careful experimental setup, the team grew a thin layer of a gold-colored metallic water on the outside of a droplet of liquid metal.

It may be surprising for most people to find out that water is actually an insulator – at least when it’s perfectly pure. The stuff that comes out of the tap, however, is a well-known conductor of electricity, due to the salts and impurities it contains. But making pure water metallic, or conductive, has long been a scientific challenge.

But now, a team of researchers from 11 institutions around the world has pulled it off at the BESSY II facility in Berlin. The key to the breakthrough was to pair the water with an alkali metal, which are known to easily release electrons from the outer shells of their atoms.

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Metamaterials research challenges fundamental limits in photonics

by Cornell University
https://phys.org/news/2021-08-metamater ... onics.html

Cornell researchers are proposing a new way to modulate both the absorptive and the refractive qualities of metamaterials in real time, and their findings open intriguing new opportunities to control, in time and space, the propagation and scattering of waves for applications in various areas of wave physics and engineering.

The research published in the journal Optica, "Spectral causality and the scattering of waves," is authored by doctoral students Zeki Hayran and Aobo Chen, M.S. '19, along with their adviser, Francesco Monticone, assistant professor in the School of Electrical and Computer Engineering in the College of Engineering.

The theoretical work aims to expand the capabilities of metamaterials to absorb or refract electromagnetic waves. Previous research was limited to modifying either absorption or refraction, but the Monticone Research Group has now shown that if both qualities are modulated in real time, the effectiveness of the metamaterial can be greatly increased.