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Category: materials – Page 181

Researchers turn discarded CDs into flexible and stretchable biosensors

The CD was initially soaked in 40 mL of acetone for 1.5 minutes, releasing the metal layer by breaking down the polycarbonate substrate. The metal from the CD was easily harvested with polyimide tape, which also serves as the substrate layer in the new device integration to improve the mechanical durability and robustness of the thin metal film.

“When you pick up your hair on your clothes with sticky tape, that is essentially the same mechanism,” said Assistant Professor Ahyeon Koh, who led the research. “We loosen the layer of metals from the CD and then pick up that metal layer with tape, so we just peel it off. That thin layer is then processed and flex ible.”

Researchers created the sensors utilizing a commercially available Cricut cutter, an off-the-shelf machine for crafters that generally cut designs from materials like paper, vinyl, card stock, and iron-on transfers. The flexible circuits then would be removed and stuck onto a person. The whole fabrication process was completed in 20–30 minutes, without releasing toxic chemicals or needing expensive equipment, and it costs about $1.50 per device.

Low-energy fluidic cells could shade and cool buildings dynamically

A large percentage of a building’s energy usage is consumed by heating and cooling, but a new dynamic shading system designed by researchers at the University of Toronto could help. Inspired by the skin of krill, the system uses cells of blooming pigment that can block light on demand.

Krill are tiny marine organisms that are usually transparent, but have the ability to move pigments around in the cells beneath their skin, allowing them to turn darker to protect themselves from UV damage in bright sunlight. This, the UToronto team reasoned, would be a useful ability for windows and building facades to have.

The team’s krill-inspired prototype is made up of optofluidic cells that can switch between transparent and opaque on demand, using relatively little energy. Inside the cell is a 1-mm layer of mineral oil between two sheets of plastic. To make it turn darker, a small amount of water containing a pigment or dye can be injected into the cell through a connected tube, creating a “bloom” of the darker color.

A non-profit removes 100,000 kg of plastic from the ‘Great Pacific Garbage Patch

Another 999 attempts and the trash will be gone forever.

The first 100,000 kg of plastic has now been recovered from the Great Pacific Garbage Patch (GPGP), The Ocean Cleanup, a non-profit organization engaged in removing plastic dumped in oceans, revealed in a LinkedIn post.

Founded in 2013, The Ocean Cleanup is developing technologies that can help remove plastics that are discarded into the oceans as well as intercept them in the rivers before they enter the larger water bodies. The organization’s target is the GPGP in the North Pacific Ocean, where trash from countries in Asia, South America, and North America gathers into a large gyre of debris in the water. ## How does The Ocean Cleanup plan to clear it?

As part of its strategy to clear up the GPGP, the organization built System 001\.

Less than a decade since its founding, The Ocean Cleanup marks a major milestone and gears up for faster and more efficient cleanup in the future.

Natural clean-up: Bacteria can remove plastic pollution from lakes

A study of 29 European lakes has found that some naturally-occurring lake bacteria grow faster and more efficiently on the remains of plastic bags than on natural matter like leaves and twigs.

The break down the compounds in plastic to use as food for their growth.

The scientists say that enriching waters with particular species of bacteria could be a natural way to remove from the environment.

Shock-formed carbon materials with intergrown sp3- and sp2-bonded nanostructured units

Studies of dense carbon materials formed by bolide impacts or produced by laboratory compression provide key information on the high-pressure behavior of carbon and for identifying and designing unique structures for technological applications. However, a major obstacle to studying and designing these materials is an incomplete understanding of their fundamental structures. Here, we report the remarkable structural diversity of cubic/hexagonally (c/h) stacked diamond and their association with diamond-graphite nanocomposites containing sp3-/sp2-bonding patterns, i.e., diaphites, from hard carbon materials formed by shock impact of graphite in the Canyon Diablo iron meteorite. We show evidence for a range of intergrowth types and nanostructures containing unusually short (0.31 nm) graphene spacings and demonstrate that previously neglected or misinterpreted Raman bands can be associated with diaphite structures. Our study provides a structural understanding of the material known as lonsdaleite, previously described as hexagonal diamond, and extends this understanding to other natural and synthetic ultrahard carbon phases. The unique three-dimensional carbon architectures encountered in shock-formed samples can place constraints on the pressure–temperature conditions experienced during an impact and provide exceptional opportunities to engineer the properties of carbon nanocomposite materials and phase assemblages.

New Graphene Electronic Tattoos Kickstart Healthcare Electronics 2.0

Graphene electronic tattoos are unique devices used in healthcare systems for personalized applications. Monolayered graphene electronic tattoos are used to monitor different electrophysiological signals in humans. Despite their innovative functionality, these devices suffer from an impermeability to sweat and difficulties in reproducibility.

Study: Graphene electronic tattoos 2.0 with enhanced performance, breathability and robustness. Image Credit: Tex vector/Shutterstock.com.

In an article recently published in the journal npj 2D Materials and Applications, an enhanced version of graphene electronic tattoos was introduced. This update is wearable on the skin with sweat permeability, superior electrical properties, and robustness. While the older systems suffered scattered electrical properties due to growth or transfer-related discrepancies, the reported graphene electronic tattoos with graphene nanoscrolls (GNS) or multilayered graphene structures showed enhanced properties.

Team tests the effects of oxygen on uranium

A team of researchers from Lawrence Livermore National Laboratory (LLNL) and the University of Michigan has found that the rate of cooling in reactions dramatically affects the type of uranium molecules that form.

The team’s experimental work, conducted over about a year and a half starting in October 2020, attempts to help understand what uranium compounds might form in the environment after a nuclear event. It has recently been detailed in Scientific Reports.

“One of our most important findings was learning that the rate of cooling affects the behavior of uranium,” said Mark Burton, the paper’s lead author and a chemist in the Lab’s Materials Science Division. “The big picture here is that we want to understand uranium chemistry in energetic environments.”