Nanocoating prevents greasy smears

Nanocoating prevents greasy smears

Not only are greasy fingerprints on shiny stainless steel surfaces unattractive, they also attack the surface. A new nanocoating being developed by Fraunhofer researchers will in the future prevent the annoying smudges that result from fingers touching stainless steel surfaces. The key to their approach: special nanoparticles added to the coating.

The shiny new refrigerator features an attractive stainless steel front. But it doesn’t take long before the door is covered in dark fingerprints that are difficult to remove with only a cloth and detergent; the job actually calls for some arduous polishing. Fingerprints like these are more than just unsightly, the grease film also attacks the metal surface.

Say goodbye to greasy smears

Together with their colleagues at FEW Chemicals GmbH in Wolfen, researchers from the Fraunhofer Institute for Microstructure of Materials and Systems IMWS in Halle are now working to put an end to smears like these. The secret lies in a coating layer containing special additives and which is water and oil repellent. This layer’s effects are twofold: When the particles integrated in the coating settle on the surface of the stainless steel, the surface becomes rougher and its surface area increases. When a finger comes into contact with the refrigerator door, it only touches the raised points on the surface and the grease on the fingertip never reaches the “valleys” of the stainless steel surface. This means the surface area which actually comes into contact with the grease is kept very small. In addition the refractive index of the coating has been adjusted so that it matches that of the skin’s natural oil content. This means light is reflected by the coated stainless steel surface in about the same manner as by a surface that has been touched by sticky fingers. As a result, the fingerprints are hardly noticeable.

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Polymer-coated gold nanospheres do not impai…

Polymer-coated gold nanospheres do not impair the innate immune function of human B lymphocytes

Over the past 20 years, the use of nanoparticles in medicine has steadily increased. However, their safety and effect on the human immune system remains an important concern. By testing a variety of gold nanoparticles, researchers at the University of Geneva (UNIGE) and collaborators are providing first evidence of their impact upon human B lymphocytes—the immune cells responsible for antibody production. The use of these nanoparticles is expected to improve the efficacy of pharmaceutical products while limiting potential adverse effects.

These results, published in the journal ACS Nano, could lead to the development of more targeted and better tolerated therapies, particularly in the field of oncology. The methodology also makes it possible to test the biocompatibility of any nanoparticle at an early stage in the development of a new nanodrug.

Responsible for the production of antibodies, B lymphocytes are a crucial part of the human immune system, and therefore an interesting target for the development of preventive and therapeutic vaccines. However, to achieve their goal, vaccines must reach B lymphocytes quickly without being destroyed, making the use of nanoparticles particularly interesting.

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Ultraviolet light-based coating shows promis…

Ultraviolet light-based coating shows promise in self-disinfecting surfaces in medical facilities, public areas

The World Health Organization warns that antibiotic resistance is one of the biggest global threats and predicts that worldwide death rates from this threat could skyrocket past 10 million a year by 2050, becoming more deadly than cancer, which kills 8.2 million people worldwide each year.

Purdue University researchers are developing a method of combating that antibiotic resistance through self-disinfecting surfaces that would kill bacteria, even those known as superbugs. The researchers are developing an ultra-thin coating, smaller than a micrometer, made of ultraviolet lightemitting diodes (UV-LED) that could be integrated into materials, such as vinyl flooring, wall coverings, door handles and even toilet seats.

“This ultra-thin coating kills any germs, bacteria, viruses, fungi and parasites. They cannot become resistant because any DNA that could make them resistant gets destroyed during the disinfection,” said Tillmann Kubis, a research assistant professor in Purdue’s School of Electrical and Computer Engineering, who is leading the research.

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A new coating material that could help reduc…

A new coating material that could help reduce thermal noise on gravity wave detector mirrors

A team of researchers from the University of Glasgow, the University of Strathclyde and Hobart and William Smith Colleges has developed a new coating for mirrors used on gravity detectors that is 25 times less noisy than mirror surfaces used on LIGO. In their paper published in the journal Physical Review Letters, the group describes how they made it and how well it performed during testing.

The mirrors used in gravity wave detectors are positioned at the ends of its arms. Coherent light rays are reflected from both mirrors and interfere with each other. Gravitational waves are measured by noting how much the mirrors shift, resulting in slight changes in length of the arms to which they are attached, to an accuracy of 10–16 cm. As impressive as that is, researchers want to improve the sensitivity of the detectors used at LIGO/Virgo, even after the recent upgrade.

To that end, members of the European Union have begun developing plans for the construction of what the Einstein Telescope, a gravitational wave detector with sensitivity 100 times higher than LIGO/Virgo. But for that to happen, improvements in the design of the current interferometer are required. One of those improvements is reducing the amount of thermal fluctuations in the mirror coatings. In this new effort, the researchers claim to have done just that.

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Researchers study super-repellent surfaces f…

Researchers study super-repellent surfaces for safer fruits, vegetables

Texas A&M AgriLife Research and the Texas A&M Engineering Experiment Station, TEES, were recently awarded a grant from the U.S. Department of Agriculture’s National Institute of Food and Agriculture to study and develop super-repellent and anti-fouling surfaces for foods.

The grant will be used in their collaboration to help ensure the safety of fresh food products, benefiting both consumers and the produce industry.

“There is a need to reduce those outbreaks associated with microbial contamination that may take place in different operations along the fresh produce chain,” said Dr. Luis Cisneros-Zevallos, AgriLife Research food scientist in College Station and co-principal investigator for the project. “The surfaces we are designing avoid cross-contamination and reduce the risk of biofilm formation.”

“In recent years, we have developed various types of nanotechnology-based coating with an intriguing combination of surface texture and chemistry to inhibit and prevent the attachment of microorganisms on plastics, metals, ceramic and glass at the laboratory scale,” said Dr. Mustafa Akbulut, TEES chemical engineer in College Station and principal investigator for the project.

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New coating could have big implications for …

New coating could have big implications for lithium batteries

Coating provides extra layer of protection for battery cathodes

Coating provides extra layer of protection for battery cathodes.

Building a better lithium-ion battery involves addressing a myriad of factors simultaneously, from keeping the battery’s cathode electrically and ionically conductive to making sure that the battery stays safe after many cycles.

In a new discovery, scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have developed a new cathode coating by using an oxidative chemical vapor deposition technique that can help solve these and several other potential issues with lithium-ion batteries all in one stroke.

“The coating we’ve discovered really hits five or six birds with one stone.” Khalil Amine, Argonne distinguished fellow and battery scientist.

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Smallest pixels ever created could light up …

Smallest pixels ever created could light up color-changing buildings

The smallest pixels yet created – a million times smaller than those in smartphones, made by trapping particles of light under tiny rocks of gold – could be used for new types of large-scale flexible displays, big enough to cover entire buildings.

The colour pixels, developed by a team of scientists led by the University of Cambridge, are compatible with roll-to-roll fabrication on flexible plastic films, dramatically reducing their production cost. The results are reported in the journal Science Advances.

It has been a long-held dream to mimic the colour-changing skin of octopus or squid, allowing people or objects to disappear into the natural background, but making large-area flexible display screens is still prohibitively expensive because they are constructed from highly precise multiple layers.

At the centre of the pixels developed by the Cambridge scientists is a tiny particle of gold a few billionths of a metre across. The grain sits on top of a reflective surface, trapping light in the gap in between. Surrounding each grain is a thin sticky coating which changes chemically when electrically switched, causing the pixel to change colour across the spectrum.

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Solar-powered hydrogen fuels a step closer

Solar-powered hydrogen fuels a step closer

Researchers have used a graphite coating that makes perovskite solar cells waterproof

A cheaper, cleaner and more sustainable way of making hydrogen fuel from water using sunlight is step closer thanks to new research from the University of Bath’s Centre for Sustainable Chemical Technologies.

With the pressure on global leaders to reduce carbon emissions significantly to solve a climate change emergency, there is an urgent need to develop cleaner energy alternatives to burning fossil fuels. Hydrogen is a zero carbon emission fuel alternative that can be used to power cars, producing only water as a waste product.

It can be made by splitting water into hydrogen and oxygen, however the process requires large amounts of electricity. Most electricity is made by burning methane so researchers at the University of Bath are developing new solar cells that use light energy directly to split water.

Most solar cells currently on the market are made of silicon, however they are expensive to make and require a lot of very pure silicon to manufacture. They are also quite thick and heavy, which limits their applications.

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Regular

Ice-proof coating for big structures relies on a ‘beautiful demonstration of mechanics’

A new class of coatings that sheds ice effortlessly from even large surfaces has moved researchers closer to their decades-long goal of ice-proofing cargo ships, airplanes, power lines and other large structures.

The spray-on coatings, developed at the University of Michigan, cause ice to fall away from structures – regardless of their size – with just the force of a light breeze, or often the weight of the ice itself. A paper on the research is published in Science.

In a test on a mock power line, the coating shed ice immediately.

The researchers overcame a major limitation of previous ice-repellent coatings – while they worked well on small areas, researchers found in field testing that they didn’t shed ice on very large surfaces as effectively as they had hoped. That’s an issue, since ice tends to cause the biggest problems on the biggest surfaces – sapping efficiency, jeopardizing safety and necessitating costly removal.

They cleared this hurdle with a “beautiful demonstration of mechanics.” Anish Tuteja, an associate professor of materials science and engineering, described how he and his colleagues turned to a property that isn’t well-known in icing research.

“For decades, coating research has focused on lowering adhesion strength – the force per unit area required to tear a sheet of ice from a surface,” Tuteja said. “The problem with this strategy is that the larger the sheet of ice, the more force is required. We found that we were bumping up against the limits of low adhesion strength, and our coatings became ineffective once the surface area got large enough.”

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Light could make some hospital surfaces deadly…

Light could make some hospital surfaces deadly to germs:

sciencenewsforstudents:

PHOENIX, Ariz. — Shining light on a new material is all it takes to make its surface toxic to germs. If used on the outside of instruments, on countertops and more, the technology might one day help hospitals limit the spread of infections, including ones that no longer respond to drugs.

Across the world, about one hospital patient in every 10 picks up a new infection while at the health care facility. That’s according to the World Health Organization. “Contaminated hospital surfaces play a key role in spreading those infections,” notes Ethel Koranteng. She’s a chemist in England at University College London.

Her team has just developed a material to make hospital surfaces self-disinfecting. Such technologies are known as “active surfaces.” That’s because they can kill germs directly. They need no additional cleansing or disinfectants.

The new material is instead based on a plastic — a flexible polymer — that can be used as a film. It might be used to cover computer keyboards, for instance. Or, the material might be molded into hard, rigid casings. These might enclose phone handles, bedrails and other easy-to-contaminate surfaces.

Other polymer-based coatings exist that resist germs. But they tend to need a spritz of water to release some germ-killing particles. The new material doesn’t. Simply turning on a room’s lights unleashes its germ-killing properties.

The idea for this is not new. Asian engineers worked on a similar sort of active surface decades ago. But that one needed a good dose of ultraviolet light to work. And that UV light can itself be hazardous to both the skin and eyes. A few years ago, two Hong Kong teens tweaked the idea to develop another UV-triggered system. It disinfects door handles (another major source of germs).

The new covering is made from polyurethane (Paa-lee-YUR-eh-thayn), a type of plastic. Embedded in it are tiny semiconductor nanobits. They’re known as quantum dots. The plastic also contains crystal violet, which is a type of purple dye. The quantum dots absorb energy from the room lighting. They then transfer some of it to the dye particles. This triggers the crystal violet to release a type of high-energy oxygen molecule. And it’s that molecule that kills germs.

In lab tests, the new material killed 99.97 percent of bacteria known as MRSA. That stands for methicillin resistant Staphylococcus aureus (Staf-uh-loh-KOK-us OR-ee-us). MRSA are immune to the germ-killing action of many antibiotics, including methicillin. The new surface was almost as good at killing a dangerous strain of E. coli. These bacteria also resists many antibiotics. What’s more, in each test, the surfaces had hosted higher levels of microbes than typically are found on hospital surfaces.

Koranteng reported her team’s success here, on April 5, at the spring national meeting of the Materials Research Society.

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