Category Archives: coatings

Sprayable gels could protect buildings during wildfires

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This seems like a good idea especially for those of us who live in areas where wildfires have become commonplace, from an August 22, 2024 news item on ScienceDaily,

As climate change creates hotter, drier conditions, we are seeing longer fire seasons with larger, more frequent wildfires. In recent years, catastrophic wildfires have destroyed homes and infrastructure, caused devastating losses in lives and livelihoods of people living in affected areas, and damaged wildland resources and the economy. We need new solutions to fight wildfires and protect areas from damage.

Researchers at Stanford have developed a water-enhancing gel that could be sprayed on homes and critical infrastructure to help keep them from burning during wildfires [emphasis mine]. The research, published Aug. 21 [2024] in Advanced Materials, shows that the new gels last longer and are significantly more effective [emphasis mine] than existing commercial gels.

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An August 21, 2024 Stanford University news release (also on EurekAlert but published August 22, 2024), which originated the news item, delves further into the research, Note: Links have been removed,

“Under typical wildfire conditions, current water-enhancing gels dry out in 45 minutes,” said Eric Appel, associate professor of materials science and engineering in the School of Engineering, who is senior author of the paper. “We’ve developed a gel that would have a broader application window – you can spray it further in advance of the fire and still get the benefit of the protection – and it will work better when the fire comes.

Long-lasting protection

Water-enhancing gels are made of super-absorbent polymers – similar to the absorbent powder found in disposable diapers. Mixed with water and sprayed on a building, they swell into a gelatinous substance that clings to the outside of the structure, creating a thick, wet shield. But the conditions in the vicinity of a wildfire are extremely dry – temperatures can be near 100 degrees, with high winds and zero percent humidity – and even water locked in a gel evaporates fairly quickly.

In the gel designed by Appel and his colleagues, the water is just the first layer of protection. In addition to a cellulose-based polymer, the gel contains silica particles, which get left behind when the gels are subjected to heat. “We have discovered a unique phenomenon where a soft, squishy hydrogel seamlessly transitions into a robust aerogel shield under heat, offering enhanced and long-lasting wildfire protection. This environmentally conscious breakthrough surpasses current commercial solutions, offering a superior and scalable defense against wildfires,” said the lead author of the study, Changxin “Lyla” Dong.

“When the water boils off and all of the cellulose burns off, we’re left with the silica particles assembled into a foam,” Appel said. “That foam is highly insulative and ends up scattering all of the heat, completely protecting the substrate underneath it.”

The silica forms an aerogel – a solid, porous structure that is a particularly good insulator. Similar silica aerogels are used in space applications because they are extremely lightweight and can prevent most methods of heat transfer.

The researchers tested several formulations of their new gel by applying them to pieces of plywood and exposing them to direct flame from a gas hand-torch, which burns at a considerably higher temperature than a wildfire. Their most effective formulation lasted for more than 7 minutes before the board began to char. When they tested a commercially available water-enhancing gel in the same way, it protected the plywood for less than 90 seconds.

“Traditional gels don’t work once they dry out,” Appel said. “Our materials form this silica aerogel when exposed to fire that continues to protect the treated substrates after all the water has evaporated. These materials can be easily washed away once the fire is gone.”

A serendipitous discovery

The new gels build off of Appel’s previous wildfire prevention work. In 2019, Appel and his colleagues used these same gels as a vehicle to hold wildland fire retardants on vegetation for months at a time. The formulation was intended to help prevent ignition in wildfire-prone areas.

“We’ve been working with this platform for years now,” Appel said. “This new development was somewhat serendipitous – we were wondering how these gels would behave on their own, so we just smushed some on a piece of wood and exposed it to flames from a torch we had laying around the lab. What we observed was this super cool outcome where the gels puffed up into an aerogel foam.”

After that initial success, it took several years of additional engineering to optimize the formulation. It is now stable in storage, easily sprayable with standard equipment, and adheres well to all kinds of surfaces. The gels are made of nontoxic components that have already been approved for use by the U.S. Forest Service, and the researchers conducted studies to show that they are easily broken down by soil microbes.

“They’re safe for both people and the environment,” Appel said. “There may need to be additional optimization, but my hope is that we can do pilot-scale application and evaluation of these gels so we can use them to help protect critical infrastructure when a fire comes through.”

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Here’s a link to and a citation for the paper,

Water-Enhancing Gels Exhibiting Heat-Activated Formation of Silica Aerogels for Protection of Critical Infrastructure During Catastrophic Wildfire by Changxin Dong, Andrea I. d’Aquino, Samya Sen, Ian A. Hall, Anthony C. Yu, Gabriel B. Crane, Jesse D. Acosta, Eric A. Appel. Advanced Materials DOI: https://doi.org/10.1002/adma.202407375 First published online: 21 August 2024

This paper is open access.

Are electrochromic films like sunglasses for your windows?

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According to a May 29, 2024 news item on ScienceDaily, elctrochromic film is like having a pair of sunglasses for your windows,

Advances in electrochromic coatings may bring us closer to environmentally friendly ways to keep inside spaces cool. Like eyeglasses that darken to provide sun protection, the optical properties of these transparent films can be tuned with electricity to block out solar heat and light. Now, researchers in ACS Energy Letters report demonstrating a new electrochromic film design based on metal-organic frameworks (MOFs) that quickly and reliably switch from transparent to glare-diminishing green to thermal-insulating red.

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This seems to be a popular way to describe electrochomic film as the title for my February 1, 2010 posting suggests, “Window sunglasses; insect microids; open access to science research?; theatre and science.”

A May 29, 2024 American Chemical Society (ACS) news release (also on EurekAlert), which originated the news item, offers more detail about how the electrochromic film works, Note: Links have been removed,

Hongbo Xu and colleagues used MOFs in their electrochromic film because of the crystalline substances’ abilities to form thin films with pore sizes that can be customized by changing the length of the organic ligand that binds to the metal ion. These features enable improved current flow, more precise control over colors and durability. In demonstrations, Xu’s MOF electrochromic film took 2 seconds to switch from colorless to green with an electric potential of 0.8 volts, and 2 seconds to switch to dark red with 1.6 V. The film maintained the green or red color for 40 hours when the potential dropped, unless a reverse voltage was applied to return the film to its transparent state. The film also performed reliably through 4,500 cycles of switching from colored to clear. With further optimization, the researchers say their tunable coatings could be used in smart windows that regulate indoor temperatures, as well as in smaller scale intelligent optical devices and sensors.

In addition to Xu’s MOF-based electrochromic film, several other research groups have reported electrochromic coating designs, including a UV-blocking but visually transparent radiative cooling film, a colorful plant-based film that gets cooler when exposed to sunlight, and a temperature-responsive film that turns darker in cold weather and lighter when it’s hot.

The authors acknowledge funding from the National Natural Science Foundation of China, Natural Science Foundation of Heilongjiang Province and the Scientific Research Startup Project of Quzhou University.

Here’s a link to and a citation for the paper,

Biphenyl Dicarboxylic-Based Ni-IRMOF-74 Film for Fast-Switching and High-Stability Electrochromism by Xueying Fan, Shen Wang, Mengyao Pan, Huan Pang, and Hongbo Xu. ACS Energy Lett. 2024, 9, 6, 2840–2847 DOI: https://doi.org/10.1021/acsenergylett.4c00492 Publication Date:May 29, 2024 Copyright © 2024 American Chemical Society

This paper is behind a paywall.

Wall paint that’s self-cleaning

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Who hasn’t had dingy walls? It seems there may be a solution at some point in the future according to a March 25, 2024 news item on ScienceDaily,

Typically, beautiful white wall paint does not stay beautiful and white forever. Often, various substances from the air accumulate on its surface. This can be a desired effect because it makes the air cleaner for a while — but over time, the colour changes and needs to be renewed.

A research team from TU Wien [Vienna University of Technology] and the Università Politecnica delle Marche (Italy) has now succeeded in developing special titanium oxide nanoparticles that can be added to ordinary, commercially available wall paint to establish self-cleaning power: The nanoparticles are photocatalytically active, they can use sunlight not only to bind substances from the air, but also to decompose them afterwards. The wall makes the air cleaner — and cleans itself at the same time. Waste was used as the raw material for the new wall paint: metal scrap, which would otherwise have to be discarded, and dried fallen leaves.

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A March 25, 2024 Vienna University of Technology press release (also on EurekAlert), which originated the news item, describes the proposed technology,

Modified titanium oxide in the wall paint

A wide variety of pollutants occur in indoor air – from residues of cleaning agents and hygiene products to molecules that are produced during cooking or that are emitted by materials such as leather. In some cases, this can lead to health issues, which is then referred to as “sick building syndrome”.

“For years, people have been trying to use customized wall paints to clean the air,” says Prof. Günther Rupprechter from the Institute of Materials Chemistry at TU Wien. “Titanium oxide nanoparticles are particularly interesting in this context. They can bind and break down a wide range of pollutants.”

However, simply adding ordinary titanium oxide nanoparticles to the paint will affect the durability of the paint: just as pollutants are degraded by the nanoparticles, they can also make the paint itself unstable and create cracks. In the worst case, volatile organic compounds can even be released, which in turn can be harmful to health. After a certain time, the paint layer becomes gray and tinted, finally it has to be renewed.

Self-cleaning by light

However, the nanoparticles can clean themselves if they are irradiated with UV light. Titanium oxide is a so-called photocatalyst – a material that enables chemical reactions when exposed to suitable light. The UV radiation creates free charge carriers in the particles, which induce decomposition of the trapped pollutants from air into small parts and their release. In this way, the pollutants are rendered harmless, but do not remain permanently attached to the wall paint. The wall colour remains stable in the long term.

In practice, however, this is of little use – after all, it would be tedious to repeatedly irradiate the wall with intense UV light in order to drive the self-cleaning process. “Our goal was therefore to modify these particles in such a way that the photocatalytic effect can also be induced by ordinary sunlight,” explains Günther Rupprechter.

This is achieved by adding certain additional atoms to the titanium oxide nanoparticles, such as phosphorus, nitrogen, and carbon. As a result, the light frequencies that can be harvested by the particles change, and instead of just UV light, photocatalysis is then also triggered by ordinary visible light.

96% pollutant removal

“We have now investigated this phenomenon in great detail using a variety of different surface and nanoparticle analysis methods,” says Qaisar Maqbool, the first author of the study. “In this way, we were able to show exactly how these particles behave, before and after they were added to the wall paint.”

The research team mixed the modified titanium oxide nanoparticles with ordinary, commercially available wall paint and rinsed a painted surface with a solution containing pollutants. Subsequently, 96% of the pollutants could be degraded by natural sunlight. The colour itself does not change – because the pollutants are not only bound, but also broken down with the help of sunlight.

Waste as a raw material

For the commercial success of such paints, it is also important to avoid expensive raw materials . “In catalysis, for example, precious metals such as platinum or gold are used. In our case, however, elements that are readily available from everywhere are sufficient: To obtain phosphorus, nitrogen and carbon, we have used dried fallen leaves from olive trees, and the titanium for the titanium oxide nanoparticles was obtained from metal waste, which is normally simply thrown away,” says Günther Rupprechter.

This new type of wall paint combines several advantages at the same time: it removes pollutants from the air, it lasts longer than other paints – and it is even more resource-saving in production as it can be obtained from recycled materials. Further experiments are being carried out, and commercialisation of the wall paint is intended.

Here’s a link to and a citation for the paper,

Highly Stable Self-Cleaning Paints Based on Waste-Valorized PNC-Doped TiO2 Nanoparticles by Qaisar Maqbool, Orlando Favoni, Thomas Wicht, Niusha Lasemi, Simona Sabbatini, Michael Stöger-Pollach, Maria Letizia Ruello, Francesca Tittarelli, and Günther Rupprechter. ACS Catal. 2024, 14, 7, 4820–4834 DOI: https://doi.org/10.1021/acscatal.3c06203 Publication Date:March 15, 2024 Copyright © 2024 The Authors. Published by American Chemical Society. This publication is licensed under
CC-BY 4.0..

This paper is open access.

Preserving stone and repairing historic Church of the Scalzi in Venice (Italy) with nanotechnology

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Since stone wear down and away with time these researchers from China and Italy are trying to find ways to mitigate the damage. (At the end of this piece I have a list of other posts about stone buildings and monuments, preservation, and nanotechnology.)

From an August 23, 2023 news snippet by Echo Xie for the South China Morning Post, Note: Links have been removed,

A team of Chinese and Italian researchers has restored parts of a 300-year-old Catholic church in Venice, Italy, using modern nanotechnology.

The Church of Santa Maria di Nazareth [Church of the Scalzi], which overlooks the Grand Canal and is a prime example of Venetian Baroque architecture, is the beneficiary of a patented method developed to consolidate, or treat, marble stones damaged by time and the elements.The research was funded by the Veneto regional government, the National Natural Science Foundation of China, and the Ministry of Science and Technology’s belt and road foreign expert exchange programme [part of the Belt and Road Initiative?].

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There’s a more extended Sept. 6, 2023 snippet about the research on Vuink,

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The cutting-edge method could be used to restore landmarks of world-class cultural heritage – including the Pantheon, Trajan’s Column and the Victoria Memorial in London as well as historic sculptures – made from marble similar to the church [Church of Santa Maria di Nazareth]

The research team, led by scientists at China’s Northwestern Polytechnical University in Xian and the CNR [National Research Council of Italy]-Institute of Geosciences and Earth Resources in Florence, Italy, found an “effective and enduring” method to consolidate marble stones after the design and systematic study of nine different treatment methods.

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Ivana Milanovic’s, ASME [American Society of Mechanical Engineers] Fellow’s Post [undated] on LinkedIn provides more details,

… They [research team] discovered the combination of two commonly used consolidation products – nanosilica and tetraethoxysilane (TEOS) – had the highest consolidating effect among all tested materials.

In the study published in the peer-reviewed journal [Science China Technological Sciences], the authors used a two-step method to consolidate the marble stones. They first applied nanosilica with dimensions less than 10nm to the surface of the stone using a poultice, a paste-like material, to cover the stone. The nanosilica particles could then penetrate as deep as 5cm (2 inches) into the pores of the stone and consolidate it. Then they used the same poultice method and put TEOS on the surface, which could enhance the stone’s hardness or mechanical strength. …

Here’s a link to and a citation for the paper,

Enhanced consolidation efficacy and durability of highly porous calcareous building stones enabled by nanosilica-based treatments by YiJian Cao, Mara Camaiti, Monica Endrizzi, Giorgio Forti, Ernesta Vergani & Ilaria Forti. Science China Technological Sciences volume 66, pages 2197–2212 (2023 Published May 18, 2023

This paper is behind a paywall. However, it is possible to request a PDF copy of the paper from the authors on their Research Gate “Enhanced consolidation efficacy and durability of highly porous calcareous building stones enabled by nanosilica-based treatments” webpage,

My other stone postings:

That should be enough, eh?

A structural colour solution for energy-saving paint (thank the butterflies)

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The UCF-developed plasmonic paint uses nanoscale structural arrangement of colorless materials — aluminum and aluminum oxide — instead of pigments to create colors. Here the plasmonic paint is applied to the wings of metal butterflies, the insect that inspired the research. Credit: University of Central Florida

A March 9, 2023 news item on Nanowerk announces research into multicolour energy-saving coating/paint, so, this is a structural colour story, Note: Links have been removed,

University of Central Florida researcher Debashis Chanda, a professor in UCF’s NanoScience Technology Center, has drawn inspiration from butterflies to create the first environmentally friendly, large-scale and multicolor alternative to pigment-based colorants, which can contribute to energy-saving efforts and help reduce global warming.

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A March 8, 2023 University of Central Florida (UCF) news release (also on EurekAlert) by Katrina Cabansay, which originated the news item, provides more context and more details,

“The range of colors and hues in the natural world are astonishing — from colorful flowers, birds and butterflies to underwater creatures like fish and cephalopods,” Chanda says. “Structural color serves as the primary color-generating mechanism in several extremely vivid species where geometrical arrangement of typically two colorless materials produces all colors. On the other hand, with manmade pigment, new molecules are needed for every color present.”

Based on such bio-inspirations, Chanda’s research group innovated a plasmonic paint, which utilizes nanoscale structural arrangement of colorless materials — aluminum and aluminum oxide — instead of pigments to create colors.

While pigment colorants control light absorption based on the electronic property of the pigment material and hence every color needs a new molecule, structural colorants control the way light is reflected, scattered or absorbed based purely on the geometrical arrangement of nanostructures.

Such structural colors are environmentally friendly as they only use metals and oxides, unlike present pigment-based colors that use artificially synthesized molecules.

The researchers have combined their structural color flakes with a commercial binder to form long-lasting paints of all colors.

“Normal color fades because pigment loses its ability to absorb photons,” Chanda says. “Here, we’re not limited by that phenomenon. Once we paint something with structural color, it should stay for centuries.”

Additionally, because plasmonic paint reflects the entire infrared spectrum, less heat is absorbed by the paint, resulting in the underneath surface staying 25 to 30 degrees Fahrenheit cooler than it would if it were covered with standard commercial paint, the researcher says.

“Over 10% of total electricity in the U.S. goes toward air conditioner usage,” Chanda says. “The temperature difference plasmonic paint promises would lead to significant energy savings. Using less electricity for cooling would also cut down carbon dioxide emissions, lessening global warming.”

Plasmonic paint is also extremely lightweight, the researcher says.

This is due to the paint’s large area-to-thickness ratio, with full coloration achieved at a paint thickness of only 150 nanometers, making it the lightest paint in the world, Chanda says.

The paint is so lightweight that only about 3 pounds of plasmonic paint could cover a Boeing 747, which normally requires more than 1,000 pounds of conventional paint, he says.

Chanda says his interest in structural color stems from the vibrancy of butterflies.

“As a kid, I always wanted to build a butterfly,” he says. “Color draws my interest.”

Future Research

Chanda says the next steps of the project include further exploration of the paint’s energy-saving aspects to improve its viability as commercial paint.

“The conventional pigment paint is made in big facilities where they can make hundreds of gallons of paint,” he says. “At this moment, unless we go through the scale-up process, it is still expensive to produce at an academic lab.”

“We need to bring something different like, non-toxicity, cooling effect, ultralight weight, to the table that other conventional paints can’t.” Chanda says.

Licensing Opportunity

For more information about licensing this technology, please visit the Inorganic Paint Pigment for Vivid Plasmonic Color technology sheet.

Researcher’s Credentials

Chanda has joint appointments in UCF’s NanoScience Technology Center, Department of Physics and College of Optics and Photonics. He received his doctorate in photonics from the University of Toronto and worked as a postdoctoral fellow at the University of Illinois at Urbana-Champaign. He joined UCF in Fall 2012.

Here’s a link to and a citation for the paper,

Ultralight plasmonic structural color paint by Pablo Cencillo-Abad, Daniel Franklin, Pamela Mastranzo-Ortega, Javier Sanchez-Mondragon, and Debashis Chanda. Science Advances 8 Mar 2023 Vol 9, Issue 10 DOI: 10.1126/sciadv.adf7207

This paper is open access.

Here’s the researcher with one of ‘his butterflies’ (I may be reading a little too much into this but it looks like he’s uncomfortable having his photo taken but game to do it for work that he’s proud of),

Caption: Debashis Chanda, a professor in UCF’s NanoScience Technology Center, drew inspiration from butterflies to create the innovative new plasmonic paint, shown here applied to metal butterfly wings. Credit: University of Central Florida

Textiles fight back bacteria with electronics

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These textiles according to an April 24, 2023 news item on SpaceDaily do a little more than fight off bacteria (as impressive as that is),

Scientists from around the world have developed a simple metallic coating treatment for clothing or wearable textiles which can repair itself, repel dangerous bacteria from the wearer and even monitor a person’s electrocardiogram (ECG) heart signals.

Researchers from North Carolina State University [US], Flinders University [Australia] and South Korea [Sungkyunkwan University (SKKU] say the conductive circuits created by liquid metal (LM) particles can transform wearable electronics and open doors for further development of human-machine interfaces, including soft robotics and health monitoring systems.

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An April 25, 2023 Flinders University press release (also on EurekAlert but published April 26, 2023), which originated the news item, provides more technical details about the conductive, self-healing textiles, Note: Links have been removed,

The ‘breathable’ electronic textiles have special connectivity powers to ‘autonomously heal’ itself even when cut, says the US team led by international expert in the field, Professor Michael Dickey.  

When the coated textiles are pressed with significant force, the particles merge into a conductive path, which enables the creation of circuits that can maintain conductivity when stretched, researchers say.   

“The conductive patterns autonomously heal when cut by forming new conductive paths along the edge of the cut, providing a self-healing feature which makes these textiles useful as circuit interconnects, Joule heaters and flexible electrodes to measure ECG signals,” says Flinders University medical biotechnology researcher Dr Khanh Truong, senior co-author in a new article in Advanced Materials Technologies. 

The technique involves dip-coating fabric into a suspension of LM particles at room temperature.  

“Evenly coated textiles remain electrically insulating due to the native oxide that forms on the LM particles. However, the insulating effect can be removed by compressing the textile to rupture the oxide and thereby allow the particles to percolate.  

“This enables the creation of conductive circuits by compressing the textile with a patterned mold. The electrical conductivity of the circuits increases by coating more particles on the textile.”  

As well the LM-coated textiles offer effective antimicrobial protection against Pseudomonas aeruginosa and Staphylococcus aureus.  

This germ repellent ability not only gives the treated fabric protective qualities but prevents the porous material from becoming contaminated if worn for and extended time, or put in contact with other people.    

The particles of gallium-based liquid metals have low melting point, metallic electrical conductivity, high thermal conductivity, effectively zero vapor pressure, low toxicity and antimicrobial properties.  

LMs have both fluidic and metallic properties so show great promise in applications such as microfluidics, soft composites, sensors, thermal switches and microelectronics.  

One of the advantages of LM is that it can be deposited and patterned at room temperature onto surfaces in unconventional ways that are not possible with solid metals. 

Here’s a link to and a citation for the paper,

Liquid Metal Coated Textiles with Autonomous Electrical Healing and Antibacterial Properties (2023) by Jiayi Yang, Praneshnandan Nithyanandam, Shreyas Kanetkar, Ki Yoon Kwon, Jinwoo Ma, Sooik Im, Ji-Hyun Oh, Mohammad Shamsi, Mike Wilkins, Michael Daniele Tae-il Kim, Huu Ngoc Nguyen, Vi Khanh Truong and Michael D Dickey. Advanced Materials Technologies Online Version of Record before inclusion in an issue 2202183 DOI: 10.1002/admt.202202183 First published: 02 April 2023 [2nd DOI:] https://doi.org/10.1002/admt.202202183 

This paper is open access.

Reducing microplastic pollution from when you wash your clothes with a new coating

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A January 26, 2023 University of Toronto news release (also found on EurekAlert and here but published on January 30, 2023) by Safa Jinje announced a coating the minimizes the amount of microplastic entering the water when your clothes are washed, Note: Links have been removed,

A team of University of Toronto Engineering researchers, led by Professor Kevin Golovin, have designed a solution to reduce the amount of microplastic fibres that are shed when clothes made of synthetic fabrics are washed.   

In a world swamped by fast fashion — an industry that produces a high-volume of cheaply made clothing at an immense cost to the environment — more than two-thirds of clothes are now made of synthetic fabrics. 

When clothes made from synthetic fabrics, such as nylon, polyester, acrylic and rayon, are washed in washing machines, the friction caused by cleaning cycles produces tiny tears in the fabric. These tears in turn cause microplastic fibres measuring less than 500 micrometres in length to break off and make their way down laundry drains to enter waterways.   

Once microplastics end up in oceans and freshwater lakes and rivers, the particles are difficult to remove and will take decades or more to fully break down. The accumulation of this debris in bodies of water can threaten marine life. It can also become part of the human food chain through its presence in food and tap water, with effects on human health that are not yet clear.  

Governments around the world have been looking for ways to minimize the pollution that comes from washing synthetic fabrics. One example is washing machine filters, which have emerged as a leading fix to stop microplastic fibres from entering waterways. In Ontario, legislative members have introduced a bill that would require filters in new washing machines in the province.  

“And yet, when we look at what governments around the world are doing, there is no trend towards preventing the creation of microplastic fibres in the first place,” says Golovin.  

“Our research is pushing in a different direction, where we actually solve the problem rather than putting a Band-Aid on the issue.”   

Golovin and his team have created a two-layer coating made of polydimethylsiloxane (PDMS) brushes, which are linear, single polymer chains grown from a substrate to form a nanoscale surface layer.  

Experiments conducted by the team showed that this coating can significantly reduce microfibre shedding of nylon clothing after repeated laundering. The researchers share their findings in a new paper published in Nature Sustainability. 

“My lab has been working with this coating on other surfaces, including glass and metals, for a few years now,” says Golovin. “One of the properties we have observed is that it is quite slippery, meaning it has very low friction.” 

PDMS is a silicon-based organic polymer that is found in many household products. Its presence in shampoos makes hair shiny and slippery. It is also used as a food additive in oils to prevent liquids from foaming when bottled. 

Dr. Sudip Kumar Lahiri, a postdoctoral researcher in Golovin’s lab and lead author of the study, had the idea that if they could reduce the friction that occurs during wash cycles with a PDMS-based fabric finish, then that could stop fibres from rubbing together and breaking off during laundering.  

One of the biggest challenges the researchers faced during their study was ensuring the PDMS brushes stayed on the fabric. Lahiri, who is a textile engineer by trade, developed a molecular primer based on his understanding of fabric dyes.  

Lahiri reasoned that the type of bonding responsible for keeping dyed apparel colourful after repeated washes could work for the PDMS coating as well.  

Neither the primer nor the PDMS brushes work separately to decrease the microplastic-fibre shedding. But together, they created a strong finish that reduced the release of microfibres by more than 90% after nine washes.  

“PDMS brushes are environmentally friendly because they are not derived from petroleum like many polymers used today,” says Golovin, who was awarded a Connaught New Researcher award for this work.  

“With the addition of Sudip’s primer, our coating is robust enough to remain on the garment and continue to reduce micro-fibre shedding over time.”  

Since PDMS is naturally a hydrophobic (water-repellent) material, the researchers are currently working on making the coating hydrophilic, so that coated fabrics will be better able to wick away sweat. The team has also expanded the research to look beyond nylon fabrics, including polyester and synthetic-fabric blends.  

“Many textiles are made of multiple types of fibres,” says Golovin. “We are working to formulate the correct polymer architecture so that our coating can durably adhere to all of those fibres simultaneously.” 

Here’s a link to and a citation for the paper,

Polydimethylsiloxane-coated textiles with minimized microplastic pollution by Sudip Kumar Lahiri, Zahra Azimi Dijvejin & Kevin Golovin. Nature Sustainability (2023) DOI: https://doi.org/10.1038/s41893-022-01059-4 Published: 26 January 2023

This paper is behind a paywall.

Nanoimaging helps unravel mystery of coating used in Stradivarius violins

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Caption: A highly precise, nanometer-scale imaging technique revealed a protein-based layer between the wood and the varnish coating of these two Stradivarius violins [images of the San Lorenzo 1718 (left) and the Toscano 1690 (right)]. Credit: Adapted from Analytical Chemistry 2022, DOI: 10.1021/acs.analchem.2c02965

An October 25, 2022 American Chemical Society (ACS) news release (also on EurekAlert) describes how the mystery of the violins was unraveled,

Stradivarius violins produce elegant music with a level of clarity that is unparalleled by modern instruments, according to some musicians. And it’s the finishing touches — mysterious treatments applied hundreds of years ago by Antonio Stradivari — that contribute to their unique look and sound. In a step toward unraveling the secret, researchers in ACS’ Analytical Chemistry report on a nanometer-scale imaging of two of Stradivari’s violins, revealing a protein-based layer between the wood and varnish.

Previous studies have reported that some stringed instruments crafted by Stradivari have a hidden coating underneath the shiny varnish. This coating’s purpose would have been to fill in and smooth out the wood, influencing the wood’s resonance and the sound that’s produced. Knowing the components of this film could be key to replicating the historic instruments in modern times. So, Lisa Vaccari, Marco Malagodi and colleagues wanted to find a technique that would determine the composition of the layer between the wood and varnish of two precious violins — the San Lorenzo 1718 and the Toscano 1690.

Using a technique previously used on historic violins, synchrotron radiation Fourier-transform infrared spectromicroscopy, the team found that both samples had an intermediary layer, but this method couldn’t differentiate the layer’s composition from the adjacent wood. Then they turned to infrared scattering-type scanning near field microscopy (IR s-SNOM) to analyze the samples. The IR s-SNOM apparatus includes a microscope that collects images tens of nanometers wide and measures the infrared light scattered from the coating layer and the wood to collect information about their chemical composition. The results of the new method showed that the layer between the wood and varnish of both instruments contained protein-based compounds, congregating in nano-sized patches. Because IR s-SNOM provided a detailed 3D picture of the types of substances on the violin’s surface, the researchers say that it could be used in future studies to identify compounds in complex multi-layer cultural heritage samples.

The authors acknowledge CERIC-ERIC [Association of European-level Research Infrastructure Facilities] and Elettra Sincrotrone Trieste for access to experimental facilities and financial support.

The American Chemical Society (ACS) is a nonprofit organization chartered by the U.S. Congress. ACS’ mission is to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and all its people. The Society is a global leader in promoting excellence in science education and providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, eBooks and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a leader in scientific information solutions, its CAS division partners with global innovators to accelerate breakthroughs by curating, connecting and analyzing the world’s scientific knowledge. ACS’ main offices are in Washington, D.C., and Columbus, Ohio.

Here’s a link to and a citation for the paper,

A Nanofocused Light on Stradivari Violins: Infrared s-SNOM Reveals New Clues Behind Craftsmanship Mastery by Chiaramaria Stani, Claudia Invernizzi, Giovanni Birarda, Patrizia Davit, Lisa Vaccari, Marco Malagodi, Monica Gulmini, and Giacomo Fiocco. Anal. Chem. 2022, 94, 43, 14815–14819 DOI: https://doi.org/10.1021/acs.analchem.2c02965 Publication Date:October 17, 2022 Copyright © 2022 American Chemical Society

This paper appears to be open access.

Nano4EARTH workshop recordings available online

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Announced in October 2022, the US government’s Nano4EARTH is the Biden-Harris {President Joe Biden and Vice President Kamala Harris] Administration’s first national nanotechnology challenge. (You can find out more about the challenge in my November 28, 2022 posting.)

More recently, JD Supra’s February 22, 2023 news item notes Nano4EARTH’s kick-off workshop (Note: Links have been removed),

The kickoff workshop for Nano4EARTH was held January 24-25, 2023. Nano4EARTH will leverage recent investments in understanding and controlling matter at the nanoscale to develop technologies, industries, and training opportunities that address climate change. On January 26, 2023, the White House Office of Science and Technology Policy (OSTP) issued a press release summarizing the workshop. According to OSTP, more than 400 people across sectors, with diverse expertise and perspectives, participated in the workshop. OSTP states that discussions focused on identifying nanotechnologies that will have an impact on climate change in four years or less, in addition to sharing resources to address barriers to entrepreneurship and technology adoption. Workshop participants identified goals and metrics to maintain momentum throughout the challenge. New connections and networks spanning federal agencies, non-federal organizations, and industry were created and several examples of collaborations and events centered on nanotechnology and climate change developed organically between participants.

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A January 26, 2023 White House Office of Science and Technology Policy (OSTP) press release, which originated the news item on JD Supra, described some common workshop themes,

  • Battery technology has seen increased adoption in personal vehicles and long-term energy storage solutions, but further advances in Li-ion, as well as new chemistries and architectures, show tremendous and broad potential. It is critical that research directions are well matched with particular use cases.
  • Catalysts leveraging new understandings of nanoscale materials and phenomena could optimize many high-greenhouse gas emitting industrial processes, minimize the need for rare-earth metals, and serve as a precursor for alternative energy sources such as green hydrogen and electrofuels. 
  • Coatings and other material innovations are likely to increase the overall efficiency of nearly any industrial process and lead to more resilient structures and devices, especially in changing and harsh environments. Examples include reflective coatings, corrosion protection, heat management in computing, lubricants and other additives, and membranes for separations. Drop-in solutions would have a more near-term impact.
  • Capture of greenhouse gasses through advanced materials and sorbents (e.g., metal organic frameworks) and nature mimicking processes (e.g., artificial photosynthesis), especially deployed at the point of production, could be impactful but deploying at scale has significant challenges. In the near term, renewable energy production and efficient transmission is worthy of increased attention.

In the months to come, the NNCO will convene a series of roundtable discussions that focus on some of the highest potential nanotechnologies identified at the kick-off workshop. Subject matter experts and federal partners will be asked to match nanotechnology opportunities to urgent climate change needs, with strong consideration of the broader societal needs and impacts. Feedback from the kick-off workshop will also inform additional activities and events to facilitate conversations and collaborations across this growing community.

The US National Nanotechnology Initiative-hosted Nano4EARTH Kick-off Workshop page features the meeting agenda where there are links to video recordings of each session.

Speaking in Color, an AI-powered paint tool

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This June 16, 2022 article by Jeff Beer for Fast Company took me in an unexpected direction but first, there’s this from Beer’s story,

If an architect wanted to create a building that matched the color of a New York City summer sunset, they’d have to pore over potentially hundreds of color cards designed for industry to get anything close, and still it’d be a tall order to find that exact match. But a new AI-powered, voice-controlled tool from Sherwin-Williams aims to change that.

The paint brand recently launched Speaking in Color, a tool that allows users to tell it about certain places, objects, or shades in order to arrive at that perfect color. You start with a broad description like, say, “New York City summer sunset,” and then fine tune from there once it responds with photos and other options with more in-depth preferences like “darker red,” “make it moodier,” or “add a sliver of sun,” until it’s done.

Developed with agency Wunderman Thompson, it’s a React web app that uses natural language to find your preferred color using both third-party and proprietary code. The tool’s custom algorithm allows you to tweak colors in a way that translates statements like “make it dimmer,” “add warmth,” or “more like the 1980s” into mathematical adjustments.

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It seems to me Wunderman Thompson needs to rethink its Sherwin Williams Speaking in Color promotional video (it’s embedded with Beer’s June 16, 2022 article or you can find it here; scroll down about 50% of the way). You’ll note, the color prompts are not spoken; they’re in text, e.g., ‘crystal-clear Caribbean ocean’. So much for ‘speaking in color’ but the article aroused my curiosity which is how I found this May 19, 2017 article by Annalee Newitz for Ars Technica highlighting another color/AI project (Note: A link has been removed),

At some point, we’ve all wondered about the incredibly strange names for paint colors. Research scientist and neural network goofball Janelle Shane took the wondering a step further. Shane decided to train a neural network to generate new paint colors, complete with appropriate names. The results are possibly the greatest work of artificial intelligence I’ve seen to date.

Writes Shane on her Tumblr, “For this experiment, I gave the neural network a list of about 7,700 Sherwin-Williams paint colors along with their RGB values. (RGB = red, green, and blue color values.) Could the neural network learn to invent new paint colors and give them attractive names?”

Shane told Ars that she chose a neural network algorithm called char-rnn, which predicts the next character in a sequence. So basically the algorithm was working on two tasks: coming up with sequences of letters to form color names, and coming up with sequences of numbers that map to an RGB value. As she checked in on the algorithm’s progress, she found that it was able to create colors long before it could actually name them reliably.

The longer it processed the dataset, the closer the algorithm got to making legit color names, though they were still mostly surreal: “Soreer Gray” is a kind of greenish color, and “Sane Green” is a purplish blue. When Shane cranked up “creativity” on the algorithm’s output, it gave her a violet color called “Dondarf” and a Kelly green called “Bylfgoam Glosd.” After churning through several more iterations of this process, Shane was able to get the algorithm to recognize some basic colors like red and gray, “though not reliably,” because she also gets a sky blue called “Gray Pubic” and a dark green called “Stoomy Brown.”

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Brown has since written a book about artificial intelligence (You Look Like a Thing and I Love You; How Artificial Intelligence Works and Why It’s Making the World a Weirder Place [2019]) and continues her investigations of AI. You can find her website and blog here and her Wikipedia entry here.