Material Science News and Discussions

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A sweet breakthrough: Scientists develop recyclable plastics based on sugars

by University of Birmingham
https://phys.org/news/2022-01-sweet-bre ... stics.html

Researchers from the University of Birmingham, U.K., and Duke University, U.S., have created a new family of polymers from sustainable sources that retain all of the qualities of common plastics, but are also degradable and mechanically recyclable.

The scientists used sugar-based starting materials rather than petrochemical derivatives to make two new polymers, one that is stretchable like rubber and another which is tough but ductile, like most commercial plastics.

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Silicon fluorescence shines through microcracks in cement, revealing early signs of damage
https://phys.org/news/2022-01-silicon-f ... aling.html
by Mike Williams, Rice University

Concrete fractures that are invisible to the naked eye stand out in images produced through a technique created at Rice University.

A collaboration between research groups at Rice and the Kuwait Institute for Scientific Research discovered by chance that common Portland cement contains microscopic crystals of silicon that emit near-infrared fluorescence when illuminated with visible light. That led to two realizations. The first was that the exact wavelength of the emission can be used to identify the particular type of cement in a structure.

The second and perhaps more important is that the near-infrared emission can reveal even very small cracks in cement or concrete. The trick is to apply a thin coat of opaque paint to the concrete when it's new. In near-infrared scans, intact concrete appears black and glowing light reveals the tiniest of cracks.

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'Atomic Armor' for accelerators enables discoveries
https://phys.org/news/2022-01-atomic-ar ... eries.html
by Los Alamos National Laboratory

Protective coatings are common for many things in daily life that see a lot of use. We coat wood floors with finish; apply Teflon to the paint on cars; even use diamond coatings on medical devices. Protective coatings are also essential in many demanding research and industrial applications.

Now, researchers at Los Alamos National Laboratory have developed and tested an atomically thin graphene coating for next-generation, electron-beam accelerator equipment—perhaps the most challenging technical application of the technology, the success of which bears out the potential for "Atomic Armor" in a range of applications.

"Accelerators are important tools for addressing some of the grand challenges faced by humanity," said Hisato Yamaguchi, member of the Sigma-2 group at the Laboratory. "Those challenges include the quest for sustainable energy, continued scaling of computational power, detection and mitigation of pathogens, and study of the structure and dynamics of the building blocks of life. And those challenges all require the ability to access, observe and control matter on the frontier timescale of electronic motion and the spatial scale of atomic bonds."

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Scientists engineer new material that can absorb and release enormous amounts of energy
https://phys.org/news/2022-02-scientist ... ounts.html
by University of Massachusetts Amherst

A team of researchers from the University of Massachusetts Amherst recently announced in the Proceedings of the National Academy of Sciences that they had engineered a new rubber-like solid substance that has surprising qualities. It can absorb and release very large quantities of energy. And it is programmable. Taken together, this new material holds great promise for a very wide array of applications, from enabling robots to have more power without using additional energy, to new helmets and protective materials that can dissipate energy much more quickly.

"Imagine a rubber band," says Alfred Crosby, professor of polymer science and engineering at UMass Amherst and the paper's senior author. "You pull it back, and when you let it go, it flies across the room. Now imagine a super rubber band. When you stretch it past a certain point, you activate extra energy stored in the material. When you let this rubber band go, it flies for a mile."

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New set of chemical building blocks makes complex 3D molecules in a snap
https://phys.org/news/2022-02-chemical- ... cules.html
by University of Illinois at Urbana-Champaign

A new set of molecular building blocks aims to make complex chemistry as simple and accessible as a toy construction kit.

Researchers at the University of Illinois Urbana-Champaign and collaborators at Revolution Medicines Inc. developed a new class of chemical building blocks that simply snap together to form 3D molecules with complex twists and turns, and an automated machine to assemble the blocks like a 3D printer for molecules.

This automation could allow chemists and nonchemists alike to develop new pharmaceuticals, materials, diagnostic probes, catalysts, perfumes, sweeteners and more, said study leader Dr. Martin D. Burke, a professor of chemistry at Illinois and a member of the Carle Illinois College of Medicine, as well as a medical doctor. The researchers reported their findings in the journal Nature.

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Super-elastic high-entropy Elinvar alloy discovered with potential for aerospace engineering
https://phys.org/news/2022-02-super-ela ... ntial.html
by City University of Hong Kong

Metals usually soften when they expand under heating, but a research team led by a City University of Hong Kong (CityU) scholar and other researchers have discovered a first-of-its-kind super-elastic alloy that can retain its stiffness even after being heated to 1,000 K (726.85 degrees Celsius) or above, with nearly zero energy dissipation. The team believes that the alloy can be applied in manufacturing high-precision devices for space missions.

The research team was led by Professor Yang Yong from CityU's Department of Mechanical Engineering (MNE) together with his collaborators. The findings were published in the science journal Nature under the title "A Highly Distorted Ultraelastic Chemically Complex Elinvar Alloy."

Challenging thermal expansion principles

Usually, the elastic modulus, i.e. stiffness, of most solids, including metals, decreases when the temperature increases as a result of thermal expansion. However, Professor Yang and his team discovered that a high-entropy alloy called Co25Ni25(HfTiZr)50, or "the high-entropy Elinvar alloy," reveals the Elinvar effect. This means the alloy firmly retains its elastic modulus over a very wide range of temperature changes.

"When this alloy is heated to 1,000 K, i.e., 726.85 degrees Celsius, or even above, it has stiffness comparable to that at room temperature, and it expands without any notable phase transition. This changes our textbook knowledge, as metals usually soften when they expand under heating," said Professor Yang.

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New material offers remarkable combo of toughness and stretchiness
https://phys.org/news/2022-02-material- ... iness.html
by North Carolina State University

Researchers have created new materials that are very stretchable and extremely tough.

"Materials that can be deformed, but that are difficult to break or tear, are desirable," says Michael Dickey, co-corresponding author of a paper on the work and the Camille & Henry Dreyfus Professor of Chemical and Biomolecular Engineering at North Carolina State University. "Nature is good at this; think of cartilage as an example. But engineering synthetic materials with these properties has been difficult, which makes our work here exciting."

The new materials fall under the broader category of ionogels, which are polymer networks that contain salts that are liquid at room temperature. These salts are called ionic liquids.

Dickey and his collaborators have made ionogels that are nearly 70% liquid, but have remarkable mechanical properties. Namely, they're tough—meaning they can dissipate a lot of energy when you deform them, making them very difficult to break. They're also easy to make, easy to process, and you can 3D print them.

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Mechanical metamaterials: Toughness and design criteria
https://phys.org/news/2022-02-mechanica ... teria.html
by Thamarasee Jeewandara , Phys.org

Mechanical metamaterials are an emerging class of materials primarily governed by their architecture to create lightweight materials with extreme mechanical properties. The functionality of such materials is limited by their tolerance to damage and defects, better known as "fracture toughness." Materials scientists credit the difficulty in part to the manufacture and characterization of a large number of unit cells. In a recent report now published on Nature Materials, Angkur Jyoti Dipanka Shaikeea and a team of scientists in engineering and metamaterials at the University of Cambridge U.K., and the University of California, Los Angeles, U.S., combined numerical and asymptotic analyses to extend the ideas of elastic fracture mechanics to mechanical 3D metamaterials and developed a design protocol to form optimally robust discrete solids.

The evolution of materials

The evolution of materials engineering has led to the development of a range of material properties with unique combinations, and the material property space can be expanded by introducing new alloys and new microstructures. Advances in additive manufacture have allowed intriguingly accurate small-scale, periodic and functionally graded architectures that can be formed into large networks to create man-made materials on the macroscopic scale known as metamaterials, alongside mechanical metamaterials more distinctly defined by their structure rather than composition.

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Strong, stretchy, self-healing polymers rapidly recover from damage
https://phys.org/news/2022-02-strong-st ... pidly.html
by RIKEN

A polymer that heals itself with unprecedented speed and efficacy when cut—almost completely recovering its original strength within minutes—has been developed by RIKEN researchers. It was produced using an advanced catalytic method for combining multiple precursors into a single polymer in a controlled fashion.

Increasing the structural complexity of polymers offers great promise for developing new materials with novel or improved properties. The controlled synthesis of complex polymers remains challenging, however.

Zhaomin Hou of the RIKEN Center for Sustainable Resource Science and his colleagues recently developed a controlled catalytic method for combining non-polar and polar olefin monomers into a single polymer. "We previously discovered that we could synthesize multiblock copolymers that exhibited excellent elasticity and self-healing by using the two-component copolymerization of non-polar ethylene and polar methoxyaryl-substituted propylenes by a half-sandwich scandium catalyst," says Hou.

The two-component polymers' properties depended strongly on the methoxyarylpropylene used. "This raised the intriguing question of whether a three-component 'terpolymer' of ethylene and two different methoxyaryl-functionalized propylenes would show unique synergistic effects on the mechanical and self-healing properties," adds Hou.

Now, Hou, four RIKEN colleagues and a collaborator have confirmed that terpolymers can show unprecedented mechanical and self-healing performance. Their elastomeric polymer could be stretched to almost 14 times its original length before breaking. And when cut in two, the polymer healed itself within five minutes to recover 99% of its toughness and 97% of its tensile strength (Fig. 1).

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Developing ultrathin films for stretchable and sturdy bioelectronic membranes

by University of California, Los Angeles

UCLA researchers have developed a unique design of ultrathin films for highly flexible yet mechanically robust bioelectronic membranes that could pave the way for diagnostic on-skin sensors that fit precisely over the body's contours and conform to its movements.

Science recently published a paper describing the research co-led by Xiangfeng Duan, professor of chemistry and biochemistry; and Yu Huang, professor and chair of the Materials Science and Engineering Department at the UCLA Samueli School of Engineering.

Held together by van der Waals forces, intermolecular interactions that can only take place at extremely close distances between atoms or molecules, the membrane is stretchable and adaptable to dynamically changing biological substrates, while being breathable and permeable to water and air. The advancement of the durable electronic material could lead to the development of noninvasive electronics for medicine, health care, biology, agriculture and horticulture. The researchers named the material van der Waals thin film, or VDWTF, which could serve as a foundational platform for living organisms to adopt electronic capabilities.

"Conceptually, the membrane is like a much-thinner version of kitchen cling film, with excellent semiconducting electronic functionality and unusual stretchability that naturally adapts to soft biological tissues with highly conformal interfaces," Duan said. "It could open up a diverse range of powerful sensing and signaling applications. For example, wearable health-monitoring devices built with this material can accurately track electrophysiological signals at the organism level or down to the level of individual cells."

https://phys.org/news/2022-03-ultrathin ... ranes.html

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Physicists Uncover the Secret Behind the Behavior of Unique Superconducting Materials
March 4, 2022

https://www.eurekalert.org/news-releases/945499

(EurekAlert)

The Science

Over the last 35 years, scientists have investigated a special type of materials called superconductors. When cooled to the correct temperatures, these materials allow electricity to flow without resistance. One team is researching superconductors using the Summit supercomputer. The team found that negative particles in the superconductors interact strongly with the smallest units of light in the materials. This interaction leads to sudden changes in the materials’ behavior. This interaction is at the root of understanding how a certain type of copper-based superconductor works.

The Impact

The team wanted to find out how the interactions between particles in the material change when they are in a crowded space with lots of other interacting particles. They hope that the results will help them better understand a unique class of superconducting materials based on copper. These materials will be more efficient than typical superconductors, thanks to their ability to work at relatively warm temperatures. This work could eventually lead to extremely efficient future electronic devices.
Summary

Researchers modeled the complicated interactions between negatively charged electron particles in a material and the interactions between electrons and phonons. Phonons are the smallest units of vibrational energy in a material. These models involved millions of particle states, with each state comprising distinct characteristics. The result is one of the team’s largest calculations to date of copper-based superconductors. The method gives the researchers a framework to study the so-called “self-energy” of electrons. The results could help the team get closer to understanding the mechanisms of a unique family of copper-based superconductors, which would be more efficient than typical copper-based superconductors.

Funding

The work was supported by the Department of Energy Office of Science through the Theory of Materials Program at Lawrence Berkeley National Laboratory and by the National Science Foundation. Advanced codes were provided by the Center for Computational Study of Excited-State Phenomena in Energy Materials (C2SEPEM). The Oak Ridge Leadership Computing Facility provided computational resources in this study. The Texas Advanced Computing Center and National Energy Research Scientific Computing Center provided additional computational resources in this study.

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Bacterial enzyme makes new type of biodegradable polymer
https://phys.org/news/2022-03-bacterial ... lymer.html
by American Chemical Society

Strings of sugars called polysaccharides are the most abundant biopolymers on Earth. Because of their versatile and environmentally friendly properties, these molecules could eventually replace some plastics. Now, researchers reporting in ACS Central Science have identified a previously unknown bacterial enzyme that can make a new type of polysaccharide, which is similar to the biopolymer chitin. The new molecule is biodegradable and could be useful for drug delivery, tissue engineering and other biomedical applications.

Polysaccharides play many roles in organisms, and because they are biocompatible and biodegradable, these molecules are promising carrier materials for a broad range of therapeutics. The identity of individual sugar molecules in the chain, and the way they are linked together, make them function in different ways. Enzymes known as glycoside phosphorylases can cut certain polysaccharides apart or make new ones, depending on the reaction conditions. For example, one such enzyme makes chitin, the major component of arthropod exoskeletons and fungal cell walls. Stephen Withers and colleagues wondered if there might be previously unknown, naturally occurring enzymes that could make new types of polysaccharides.

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Researchers discover new form of ice

by Natalie Bruzda, University of Nevada, Las Vegas
https://phys.org/news/2022-03-ice.html

UNLV researchers have discovered a new form of ice, redefining the properties of water at high pressures.

Solid water, or ice, is like many other materials in that it can form different solid materials based on variable temperature and pressure conditions, like carbon forming diamond or graphite. However, water is exceptional in this aspect as there are at least 20 solid forms of ice known to us.

A team of scientists working in UNLV's Nevada Extreme Conditions Lab pioneered a new method for measuring the properties of water under high pressure. The water sample was first squeezed between the tips of two opposite-facing diamonds—freezing into several jumbled ice crystals. The ice was then subjected to a laser-heating technique that temporarily melted it before it quickly re-formed into a powder-like collection of tiny crystals.

By incrementally raising the pressure, and periodically blasting it with the laser beam, the team observed the water ice make the transition from a known cubic phase, Ice-VII, to the newly discovered intermediate, and tetragonal, phase, Ice-VIIt, before settling into another known phase, Ice-X.

Zach Grande, a UNLV Ph.D. student, led the work which also demonstrated that the transition to Ice-X, when water stiffens aggressively, occurs at much lower pressures than previously thought.

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Concrete made with old tires proves itself in real-world setting
By Nick Lavars
March 30, 2022
https://newatlas.com/materials/crumb-ru ... ding-slab/

With a notoriously large carbon footprint, concrete is a prime target for researchers developing greener materials for the future of construction. A number of studies have shown how old rubber tires can be used to make versions that are stronger, more heat-resistant and flexible enough for use as a road material. A new study has assessed its value in real-world settings by using concrete containing old tires as a residential slab and monitoring its performance over several years, where it outshone conventional concrete in a number of ways.

The type of concrete at the center of this study is known as crumb rubber concrete, and its production involves grinding rubber tire down into crumbs of a similar consistency to sand. These crumbs can then be used to replace a certain proportion of the sand typically mixed in with the cement, water and other ingredients to form concrete, lessening the reliance on the natural material and giving the discarded rubber a second life.

Scientists at the University of South Australia and Melbourne's RMIT University have sought to take this material from the "lab to the slab," noting that while it has shown a lot of promise in laboratory testing, its reliability in real-world construction requires further exploration.

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Manganese oxide material can rapidly store and release low-grade heat without decomposing
https://phys.org/news/2022-04-manganese ... grade.html
by Tohoku University

Scientists in Japan have found a common substance that can reversibly and rapidly store and release relatively large amounts of low-grade heat without decomposing. The research could lead to more efficient reuse of industrial waste heat. The results were published in the journal Nature Communications and were a collaboration between scientists at Tohoku University's Institute for Materials Research and Rigaku Corporation, a company that designs and manufactures X-ray-based measurement and thermal analysis tools.

In their investigations, the researchers used a layered manganese oxide mineral containing potassium ions and crystal water. This mineral is quite similar in its composition to birnessite, which is commonly found on the Earth's surface. The team fabricated their compound in the form of an insoluble black powder and then examined its crystal structure using an X-ray diffractometer and a transmission electron microscope. They then examined how the compound's structure changed when heated or cooled, and how much and how quickly heat energy was stored and released.

Heating the material up to 200︎ degrees Celsius dehydrated it by giving its stored water molecules the energy they need to be released into the surrounding atmosphere. When the dehydrated material was then cooled below 120︎C in a dry container and then exposed to humid air, it absorbed water molecules and released its stored heat.

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Shedding new light on controlling material properties in solid-layered perovskite
https://phys.org/news/2022-04-material- ... skite.html
by Kyoto University

Materials scientists may soon be able to control material properties with light.

A team consisting of researchers at Kyoto University and Kurume Institute of Technology have discovered a scaling law that determines high-order harmonic generation in the solid-layered perovskite material, Ca2RuO4.

High-order harmonic generation is a nonlinear optical phenomenon where extreme ultraviolet photons are emitted by a material as a result of interactions with high intensity light.

"The phenomenon, which was first observed in atomic gas systems, has since paved the way to attosecond science," says study author Kento Uchida. "But it is slightly more unpredictable in some strongly correlated solids, like Ca2RuO4."

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A new class of catalysts for environmentally-friendly coatings
https://phys.org/news/2022-04-class-cat ... tings.html
by University of Konstanz

Chemists from Konstanz have developed a new class of catalysts that enable manufacturing of polyethylene dispersions directly in water. This opens up perspectives for the environmentally-friendly, solvent-free production of plastic coatings.

Polyethylene (PE) is one of today's most important types of plastic. It is used in a wide range of everyday objects—from plastic bottles to pipes, ski coatings and toys. In the form of PE dispersions, it also forms the basis for different coatings and adhesives.

Professor Stefan Mecking and Dr. Fei Lin from the Department of Chemistry at the University of Konstanz have now taken a big step closer to the environmentally-friendly, solvent-free production of PE coatings. In their recent article in the international edition of the journal Angewandte Chemie International Edition, the chemists describe a new class of water-soluble catalysts that make it possible to manufacture PE dispersions directly in water. This eliminates energy-intensive intermediate steps in the production of solvent-free, emission-free coatings.

Organic solvents as the existing industry standard

Because of their technical characteristics and their comparatively low production costs, plastics have become an essential industrial material. They are comprised of large, long-chain molecules that, depending on the type, can also be branched polymers and are composed of many repeat units formed from basic building blocks. In the case of polyethylene, the basic building block is ethylene—a gaseous hydrocarbon compound.

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Building nanoalloy libraries from laser-induced thermionic emission reduction experiments
https://phys.org/news/2022-05-nanoalloy ... ssion.html
by Thamarasee Jeewandara , Phys.org

High-entropy nanoalloys (HENA) have widespread applications in materials science and applied physics. However, their synthesis is challenging due to slow kinetics that cause phase segregation, sophisticated pretreatment of precursors, and inert conditions. In a new report now published in Science Advances, Haoqing Jiang and a team of scientists in industrial engineering, nanotechnology and materials science in the U.S., and China, described a process of converting metal salts to ultrafine HENAs on carbonaceous supports using nanosecond pulse lasers. Based on the unique laser induced thermionic emission and etch on carbon, the team gathered the reduced metal elements of ultrafine HENAs stabilized via the defective carbon support. The resulting process produced a variety of HENAs ranging from 1-to-3 nanometers and metal elements of up to 11 grams per hour, with a productivity reaching 7 grams per hour. The HENAs exhibited excellent catalytic performance during oxygen reduction, with great practical potential.

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Scientists develop powerful family of 2D materials
https://phys.org/news/2022-05-scientist ... rials.html
by Barri Bronston, Tulane University

A team from the Tulane University School of Science and Engineering has developed a new family of two-dimensional materials that researchers say has promising applications, including in advanced electronics and high-capacity batteries.

Led by Michael Naguib, an assistant professor in the Department of Physics and Engineering Physics, the study has been published in the journal Advanced Materials.

"Two-dimensional materials are nanomaterials with thickness in the nanometer size (nanometer is one millionth of a millimeter) and lateral dimensions thousands of times the thickness," Naguib said. "Their flatness offers unique set of properties compared to bulk materials."

The name of the new family of 2D materials is transition metal carbo-chalcogenides, or TMCC. It combines the characteristics of two families of 2D materials—transition metal carbides and transition metal dichalcogenides.

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Researchers develop 3D-printed shape memory alloy with superior superelasticity
https://phys.org/news/2022-05-3d-printe ... icity.html
by Michelle Revels, Texas A&M University

Laser powder bed fusion, a 3D-printing technique, offers potential in the manufacturing industry, particularly when fabricating nickel-titanium shape memory alloys with complex geometries. Although this manufacturing technique is attractive for applications in the biomedical and aerospace fields, it has rarely showcased the superelasticity required for specific applications using nickel-titanium shape memory alloys. Defects generated and changes imposed onto the material during the 3D-printing process prevented the superelasticity from appearing in 3D-printed nickel-titanium.

Researchers from Texas A&M University recently showcased superior tensile superelasticity by fabricating a shape memory alloy through laser powder bed fusion, nearly doubling the maximum superelasticity reported in literature for 3D printing.

This study was recently published in vol. 229 of the Acta Materialia journal.

Nickel-titanium shape memory alloys have various applications due to their ability to return to their original shape upon heating or upon removal of the applied stress. Therefore, they can be used in biomedical and aerospace fields for stents, implants, surgical devices and aircraft wings. However, developing and properly fabricating these materials requires extensive research to characterize functional properties and examine the microstructure.