Material Science News and Discussions

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Researchers create photonic materials for powerful, efficient light-based computing

by Robert Wells, University of Central Florida

University of Central Florida researchers are developing new photonic materials that could one day help enable low power, ultra-fast, light-based computing.

The unique materials, known as topological insulators, are like wires that have been turned inside out, where the current runs along the outside and the interior is insulated.

Topological insulators are important because they could be used in circuit designs that allow for more processing power to be crammed into a small space without generating heat, thus avoiding the overheating problem today's smaller and smaller circuits face.

https://phys.org/news/2022-05-photonic- ... based.html

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Researchers unveil a secret of stronger metals
https://phys.org/news/2022-05-unveil-se ... etals.html
by David L. Chandler, Massachusetts Institute of Technology

For the first time, researchers have described how the tiny crystalline grains that make up most solid metals actually form. Understanding this process, they say, could theoretically lead to ways of producing stronger, lighter versions of widely used metals such as aluminum, steel and titanium. Credit: Massachusetts Institute of Technology

Forming metal into the shapes needed for various purposes can be done in many ways, including casting, machining, rolling, and forging. These processes affect the sizes and shapes of the tiny crystalline grains that make up the bulk metal, whether it be steel, aluminum or other widely used metals and alloys.

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Transparency on demand: A novel process can render artificial materials transparent or even entirely invisible
https://phys.org/news/2022-05-transpare ... arent.html
by Sissy Gudat, University of Rostock

Space, the final frontier. The starship Enterprise pursues its mission to explore the galaxy, when all communication channels are suddenly cut off by an impenetrable nebula. In many episodes of the iconic TV series, the valiant crew must "tech the tech" and "science the science" within just 45 minutes of airtime in order to facilitate their escape from this or a similar predicament before the end credits roll. Despite spending a significantly longer time in their laboratories, a team of scientists from the University of Rostock has succeeded in developing an entirely new approach for the design of artificial materials that can transmit light signals without any distortions by means of precisely tuned flows of energy. They have published their results in Science Advances.

"When light spreads in an inhomogeneous medium, it undergoes scattering. This effect quickly transforms a compact, directed beam into a diffuse glow, and is familiar to all of us from summer clouds and autumn fog alike," Professor Alexander Szameit of the Institute for Physics at the University of Rostock describes the starting point of his team's considerations. Notably, it is the microscopic density distribution of a material that dictates the specifics of scattering. Szameit continues, "The fundamental idea of induced transparency is to take advantage of a much lesser-known optical property to clear a path for the beam, so to speak."

This second property, known in the field of photonics under the arcane title of non-Hermiticity, describes the flow of energy, or, more precisely, the amplification and attenuation of light. Intuitively, the associated effects may seem undesirable—particularly the fading of a light beam due to absorption would seem highly counterproductive to the task of improving signal transmission. Nevertheless, non-Hermitian effects have become a key aspect of modern optics, and an entire field of research strives to harness the sophisticated interplay of losses and amplification for advanced functionalities.

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Can we make graphite from coal? Researchers start by finding new carbon solid

by Ohio University
https://phys.org/news/2022-06-graphite- ... solid.html

As the world's appetite for carbon-based materials like graphite increases, Ohio University researchers presented evidence this week for a new carbon solid they named "amorphous graphite."

Physicist David Drabold and engineer Jason Trembly started with the question, "Can we make graphite from coal?"

"Graphite is an important carbon material with many uses. A burgeoning application for graphite is for battery anodes in lithium-ion batteries, and it is crucial for the electric vehicle industry—a Tesla Model S on average needs 54 kg of graphite. Such electrodes are best if made with pure carbon materials, which are becoming more difficult to obtain owing to spiraling technological demand," they write in their paper, "Ab initio simulation of amorphous graphite," that published today in Physical Review Letters.

"Ab initio" means "from the beginning," and their work pursues novel paths to synthetic forms of graphite from naturally occurring carbonaceous material. What they found, with several different calculations, was a layered material that forms at very high temperatures (about 3000 degrees Kelvin). Its layers stay together due to the formation of an electron gas between the layers, but they're not the perfect layers of hexagons that make up ideal graphene. This new material has plenty of hexagons, but also pentagons and heptagons. That ring disorder reduces the electrical conductivity of the new material compared with graphene, but the conductivity is still high in the regions dominated largely by hexagons.

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Scientists develop antimicrobial, plant-based food wrap designed to replace plastic
https://phys.org/news/2022-06-scientist ... astic.html
by Rutgers University

Aiming to produce environmentally friendly alternatives to plastic food wrap and containers, a Rutgers scientist has developed a biodegradable, plant-based coating that can be sprayed on foods, guarding against pathogenic and spoilage microorganisms and transportation damage.

The scalable process could potentially reduce the adverse environmental impact of plastic food packaging as well as protect human health.

"We knew we needed to get rid of the petroleum-based food packaging that is out there and replace it with something more sustainable, biodegradable and nontoxic," said Philip Demokritou, director of the Nanoscience and Advanced Materials Research Center, and the Henry Rutgers Chair in Nanoscience and Environmental Bioengineering at the Rutgers School of Public Health and Environmental and Occupational Health Sciences Institute. "And we asked ourselves at the same time, 'Can we design food packaging with a functionality to extend shelf life and reduce food waste while enhancing food safety?'''

Demokritou added, "And what we have come up with is a scalable technology, which enables us to turn biopolymers, which can be derived as part of a circular economy from food waste, into smart fibers that can wrap food directly. This is part of new generation, 'smart' and 'green' food packaging."

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Cooking up a conductive alternative to copper with aluminum
https://phys.org/news/2022-06-cooking-a ... minum.html
by Alexandra Freibott, Pacific Northwest National Laboratory

In the world of electricity, copper is king—for now. That could change with new research from Pacific Northwest National Laboratory (PNNL) that is serving up a recipe to increase the conductivity of aluminum, making it economically competitive with copper. This research opens the door to experiments that—if fully realized—could lead to an ultra-conductive aluminum alternative to copper that would be useful in markets beyond transmission lines, revolutionizing vehicles, electronics, and the power grid.

"What if you could make aluminum more conductive—even 80% or 90% as conductive as copper? You could replace copper and that would make a massive difference because more conductive aluminum is lighter, cheaper, and more abundant," said Keerti Kappagantula, PNNL materials scientist and co-author on the research. "That's the big picture problem that we're trying to solve."

Copper vs. aluminum

Copper demand is fast outpacing its current availability, driving up its cost. Copper is a great electrical conductor—it's used in everything from handheld electronics to underwater transmission cables that power the internet—but there's no escaping the fact that copper is becoming less available and more expensive. These challenges are only expected to get worse with the rising number of electric vehicles (EVs), which need twice as much copper as traditional vehicles. Plus, copper is heavy, which drives down EV efficiency.

Aluminum is just one-third the price and weight of copper, but it is only about 60% as conductive. Aluminum's relatively low conductivity can be a limitation in some real-world applications.

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A ceramic aerogel made with nanocrystals and embedded in a matrix for use in thermal insulation applications
https://phys.org/news/2022-07-ceramic-a ... atrix.html
by Bob Yirka , Phys.org

A team of researchers at the Harbin Institute of Technology, in China, working with a colleague in the U.S., has developed a new kind of aerogel for use in flexible thermal insulation material applications. In their paper published in the journal Nature, the group describes how they made their aerogel and how well it worked when extreme heat was applied.

Prior work has shown that aerogels made using ceramic materials work very well as thermal insulators—their very low densities have very low thermal conductivity. But such materials are brittle, making them unavailable for use in flexible material applications, such as suits for firefighters. They also tend to break down when exposed to very high temperatures. In this new effort, the researchers have developed a method for making a ceramic based aerogel that can be used in flexible applications and also does not break down when exposed to very high temperatures.

To create their aerogel, the researchers took a novel approach—they pushed a zirconium-silicon precursor, using a plastic syringe, into a chamber with turbulent airflow—an electrospinning approach that produced a ceramic material that resembled cotton candy. They then folded the resulting material into a zig-zag pattern and heated it to 1100° C. Heating it in such a way changed the texture of the material from a glassy state to a nanocrystal. Study of the resulting material using a spectroscope showed that their approach had resulted in the creation of a material with nanocrystalline bits embedded in an amorphous zircon matrix—a flexible aerogel made using a ceramic that was not prone to breaking down under high temperatures.

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Characterizing the materials for next-generation quantum computers with nonlinear optical spectroscopy
https://phys.org/news/2022-07-character ... inear.html
by Universität Hamburg

Researchers at the Department of Physics and the Cluster of Excellence "CUI: Advanced Imaging of Matter" of Universität Hamburg and the University of California at Irvine have recently proposed a new way to characterize topological superconductors by means of multi-THz-pulse experiments.

This opens a pathway to unambiguously identifying predicted exotic states of matter and can aid in the design of novel materials for future devices that carry and process quantum information.

Scientists around the world are working to build scalable quantum computers based on solid-state matter. One such class of materials are topological superconductors. They are purported to host a particular kind of collective quantum state, the non-abelian anyons in the form of Majorana fermions at their boundaries. By shuffling these quasiparticles around in networks of quantum wires, researchers can construct logical quantum gates, the building blocks of quantum computers.

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Scientists develop durable material for flexible artificial muscles
https://phys.org/news/2022-07-scientist ... icial.html
by University of California, Los Angeles

UCLA materials scientists and colleagues at the nonprofit scientific research institute SRI International have developed a new material and manufacturing process for creating artificial muscles that are stronger and more flexible than their biological counterparts.

"Creating an artificial muscle to enable work and detect force and touch has been one of the grand challenges of science and engineering," said Qibing Pei, a professor of materials science and engineering at the UCLA Samueli School of Engineering and the corresponding author of a study recently published in Science.

In order for a soft material to be considered for use as an artificial muscle, it must be able to output mechanical energy and remain viable under high-strain conditions—meaning it does not easily lose its form and strength after repeated work cycles. While many materials have been considered contenders for making artificial muscles, dielectric elastomers (DE)—lightweight materials with high elastic energy density—have been of special interest because of their optimal flexibility and toughness.

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Designer materials to keep plastic out of landfills
https://phys.org/news/2022-07-materials ... fills.html
by Alison Hatt, Lawrence Berkeley National Laboratory

Scientists have designed a new material system to overcome one of the biggest challenges in recycling consumer products: mixed-plastic recycling. Their achievement will help enable a much broader range of fully recyclable plastic products and brings into reach to an efficient circular economy for durable goods like automobiles.

We generate staggering quantities of plastic and plastic-containing products each year, but only a tiny fraction of that plastic can be recovered and used to manufacture products of similar quality. That's because most products, from food-packaging films and single-use bags to sneakers and electronics, are made from mixtures of different plastics, and once they are mixed, those plastics can't be recovered and used to make new bags or sneakers. Instead, most of it ends up in landfills, incinerators, or oceans.

A team of scientists from Lawrence Berkeley National Laboratory (Berkeley Lab) are tackling the mixed-plastic challenge using a custom-designed material called polydiketoenamine (PDK), a new type of plastic they developed to be recycled efficiently and indefinitely, providing a low-carbon manufacturing solution for plastic products that never have to end up in a landfill.

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New bioremediation material can clean 'forever chemicals'
https://phys.org/news/2022-07-bioremedi ... icals.html
by Helen White, Texas A&M University

A novel bioremediation technology for cleaning up per- and polyfluoroalkyl substances, or PFAS, chemical pollutants that threaten human health and ecosystem sustainability, has been developed by Texas A&M AgriLife researchers. The material has potential for commercial application for disposing of PFAS, also known as "forever chemicals."

Published July 28 in Nature Communications, the research was a collaboration of Susie Dai, Ph.D., associate professor in the Texas A&M Department of Plant Pathology and Microbiology, and Joshua Yuan, Ph.D., chair and professor in Washington University in St. Louis Department of Energy, Environmental and Chemical Engineering, formerly with the Texas A&M Department of Plant Pathology and Microbiology.

Removing PFAS contamination is a challenge

PFAS are used in many applications such as food wrappers and packaging, dental floss, fire-fighting foam, nonstick cookware, textiles and electronics. These days, PFAS are widely distributed in the environment from manufacturing or from products containing the chemicals, said Dai.

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New adaptive artificial muscles made of a single-helical woolen yarn
https://techxplore.com/news/2022-08-art ... -yarn.html
by Ingrid Fadelli , Tech Xplore

In recent years, material scientists have designed a wide range of innovative materials that could be used to create new technologies, including soft robots, controllers and smart textiles. These materials include artificial muscles, structures that resemble biological muscles in shape and that could improve the movements of robots or enable the creation of clothing that adapts to different environmental conditions.

As part of an ongoing project focused on textile-based soft actuators, a team of researchers at Jiangnan University in China recently developed new artificial muscles based on free-standing, single-helical woolen yarn. Their artificial muscles, introduced in a paper published in Smart Materials and Structures, could be used to easily and affordably produce twisted actuators that can detect and respond to humidity in their environment.

"We are trying to design flexible and versatile actuators by leveraging the hierarchical structure design of textiles, ranging from microscales (e.g., molecular chains and aggregation structures) to macroscales (e.g., fiber morphology and textile architectures)," Fengxin Sun, one of the researchers who carried out the study, told Tech Xplore. "Realizing a yarn-based artificial muscle with free-standing and single-helical architecture via eco-friendly and easy-fabrication manufacturing process is still challenging."

The primary objective of the recent work by Sun and his colleagues was to overcome some of the common challenges faced when designing artificial muscles based on yarn (i.e., spun thread). Most notably, past studies have showed that reliably twisting yarn to create free-standing artificial muscle structures without using harmful chemicals or processes is far from an easy task.

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Protective coating material self-heals in 30 minutes when exposed to sunlight
https://phys.org/news/2022-08-coating-m ... posed.html
by National Research Council of Science & Technology

Researchers have developed a transparent protective coating material that can self-heal in 30 minutes when exposed to sunlight.

Excellent durability of automotive coatings is the most important issue in protecting a vehicle surface. In addition, protective coating materials should be colorless and transparent so that the original color of the product can be seen. However, it is difficult to provide a self-healing function while satisfying all of these conditions. Materials with free molecular movement have high self-healing efficiency, but have low durability, whereas materials with high hardness and excellent durability have remarkably poor self-healing performance.

The research team of Dr. Jin Chul Kim, Dr. Young il Park, and Dr. Ji-Eun Jeong of the Korea Research Institute of Chemical Technology (KRICT) has developed a transparent coating material that satisfies all of the above conditions and has similar performance to that of commercial protective coating materials and can be self-healed with only sunlight (particularly near infrared light in sunlight, in the wavelength range of 1,000 to 1,100 nm).

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Scientists discover a new mechanism to increase the strength and ductility of high-entropy alloys
https://phys.org/news/2022-08-scientist ... tropy.html
by City University of Hong Kong

A research team co-led by materials scientists from City University of Hong Kong (CityU) has recently discovered a new mechanism to increase the strength and ductility of a high-entropy alloy, two properties which normally vary inversely with each other. The findings provide important insights for the future design of strong yet ductile high-entropy alloys and high-entropy ceramics.

The strength-ductility trade-off is a longstanding issue for conventional alloys that are usually based on one or two principal elements, meaning that increasing the strength usually sacrifices ductility. In the past decade, a new alloy design strategy was proposed: mixing multiple elements to form alloys, termed "multi-principal element alloys" (MPEAs) or "high-entropy alloys" (HEAs). MPEAs exhibit excellent mechanical properties, such as both great ductility and superb strength.

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A simple way of sculpting matter into complex shapes
https://phys.org/news/2022-08-simple-sc ... mplex.html
by University of Strathclyde, Glasgow

A new method for shaping matter into complex shapes, with the use of 'twisted' light, has been demonstrated in research at the University of Strathclyde.

When atoms are cooled to temperatures close to absolute zero (-273 degrees C), they stop behaving like particles and start to behave like waves.

Atoms in this condition, which are known as Bose–Einstein condensates (BECs), are useful for purposes such as realization of atom lasers, slow light, quantum simulations for understanding the complex behavior of materials like superconductors and superfluids, and the precision measurement technique of atom interferometry.

The Strathclyde study has shown that when twisted light is shone on to a moving BEC, it breaks into clusters of BEC droplets that move following the light's features, with the number of droplets equal to twice the number of light twists. Altering the properties of the light beam can change both the number of BEC droplets and the way that they move.

The research has been published in Physical Review Letters.

Grant Henderson, a Ph.D. student in Strathclyde's Department of Physics, is lead author on the paper. He said: "By shining a laser beam on to a BEC, we can influence how it behaves. When the laser beam is "twisted," it has a helical phase profile and carries orbital angular momentum (OAM). Laser beams with OAM can trap and rotate microscopic particles, behaving like an optical spanner.

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Manufacturing metal-organic framework-based composites for efficiency
https://phys.org/news/2022-08-metal-org ... iency.html
by Michelle Revels, Texas A&M University

Dr. Qingsheng Wang, associate professor and George Armistead '23 Faculty Fellow in the Artie McFerrin Department of Chemical Engineering at Texas A&M University, and his team of researchers have spent over three years finding more efficient ways to manufacture metal-organic framework (MOF)-based composites for industrial applications such as flame retardants.

MOFs are a class of crystalline materials with permanent porosity and wide applications, including gas purification, gas separation, water remediation, catalysis and drug delivery. However, process improvement is required to produce MOFs at a higher capacity in industry as the use and applications of MOF-based composites expand.

"To produce MOFs requires a deep understanding of process engineering and stringent conditions, and even with that, only a small amount can be produced at a time," said Wang. "Many alterations are needed to improve the process if we want to mass-produce MOFs."

Wang's group has published four studies in ACS Publications regarding their discoveries on MOF stability, MOF development processes, manufacturing MOF-based composites and their applications in flame retardancy.

Currently, most MOF-polymer composites are prepared by a discretely bottom-up principle that requires complex chemical reactions blended within different polymers in solutions. This multi-step process entails significant time, energy and money to produce minimal quantities.

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Cage with caps: Selective confinement of rare-earth-metal hydrates in host molecules

by Wiley
https://phys.org/news/2022-08-cage-caps ... rates.html

Rare-earth metals are indispensable for many technical products, from smartphones, laptops, batteries, electromotors, and wind turbines, to catalysts. In the journal Angewandte Chemie, a Japanese team has now introduced a molecular "cage" with "caps" that can be used to selectively "confine" certain rare-earth-metal ions for isolation or recycling.

The rare-earth elements include 17 metals: scandium, yttrium, lanthanum, and the lanthanides, the 14 elements that follow after lanthanum in the periodic table, including neodymium and europium. The name is misleading because the rare-earth metals are not actually rare. They are everywhere in the environment but are highly dispersed and bound in minerals ("earths"); large deposits are rare. Reclaiming these elements from electronic waste is becoming more important. Some microorganisms have been discovered that contain enzymes with rare-earth metals. These could be useful in extraction and reclamation and provide inspiration for the use of rare-earth metals as catalysts.

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Researchers engineer novel material capable of 'thinking'
https://techxplore.com/news/2022-08-mat ... pable.html
by Pennsylvania State University

Someone taps your shoulder. The organized touch receptors in your skin send a message to your brain, which processes the information and directs you to look left, in the direction of the tap. Now, Penn State and U.S. Air Force researchers have harnessed this processing of mechanical information and integrated it into engineered materials that "think".

The work, published today in Nature, hinges on a novel, reconfigurable alternative to integrated circuits. Integrated circuits are typically composed of multiple electronic components housed on a single semiconductor material, usually silicon, and they run all types of modern electronics, including phones, cars and robots. Integrated circuits are scientists' realization of information processing similar to the brain's role in the human body. According to principal investigator Ryan Harne, James F. Will Career Development Associate Professor of Mechanical Engineering at Penn State, integrated circuits are the core constituent needed for scalable computing of signals and information but have never before been realized by scientists in any composition other than silicon semiconductors.

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Serendipitous backyard experiment shines light on producing polymers
https://phys.org/news/2022-09-serendipi ... ymers.html
by Queensland University of Technology

QUT researchers who conducted their experiment in a Brisbane backyard have found an unprecedented methodology for the production of microspheres.

Their research, reported in the journal Nature Communications, is a result of a series of factors, including the COVID lockdown which impacted laboratory access, a decision to investigate a waste product and more than a decade of cutting-edge research into the power of light to make molecules.

Polymer microspheres—spheres that are 1000 times smaller than 1 mm—are used in a wide range of applications including drug delivery, pharmaceuticals, cosmetics and paints. An example of their everyday use is that microspheres enable the now iconic display of the one or two stripes on pregnancy tests or rapid antigen tests for SARS-CoV-2 infections.

Microspheres are typically produced in a process in which chemicals are heated, requiring substantial amounts of energy and can cause problems of overeating and uncontrolled reactions.

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Newly developed ice-shedding coating is 100 times stronger than others

by Laurie Fickman, University of Houston
https://phys.org/news/2022-09-newly-ice ... onger.html

A University of Houston mechanical engineer has developed a sprayable ice-shedding material that is 100 times stronger than any others. The new durable coating material has been tested by Boeing under erosive rain conditions at 385 miles per hour and has outperformed current state-of-the-art aerospace coating technologies.

The principle of the new "fracture-controlled material" lies in the fact that for detachment of any external solid object from a surface (like ice from an airplane wing), force must be applied, and that force will inevitably lead to formation of some cracks at the interface. These cracks (or fractures) grow until full detachment of the object from the surface.

Through a new concept developed by Hadi Ghasemi, Cullen Associate Professor of Mechanical Engineering, detachment can be accurately controlled and accelerated.