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Science

Scientists Create Eco-Friendly Paint That Keeps the Surface Beneath Cool 49

A team of researchers in Florida have created a way to mimic nature's ability to reflect light and create beautifully vivid color without absorbing any heat like traditional pigments do. Debashis Chanda, a nanoscience researcher with the University of Central Florida, and his team published their findings in the journal Science Advances. NPR reports: Beyond just the beautiful arrays of color that structure can create, Chanda also found that unlike pigments, structural paint does not absorb any infrared light. Infrared light is the reason black cars get hot on sunny days and asphalt is hot to the touch in summer. Infrared light is absorbed as heat energy into these surfaces -- the darker the color, the more the surface colored with it can absorb. That's why people are advised to wear lighter colors in hotter climates and why many buildings are painted bright whites and beiges. Chanda found that structural color paint does not absorb any heat. It reflects all infrared light back out. This means that in a rapidly warming climate, this paint could help communities keep cool.

Chanda and his team tested the impact this paint had on the temperature of buildings covered in structural paint versus commercial paints and they found that structural paint kept surfaces 20 to 30 degrees cooler. This, Chanda said, is a massive new tool that could be used to fight rising temperatures caused by global warming while still allowing us to have a bright and colorful world. Unlike white and black cars, structural paint's ability to reflect heat isn't determined by how dark the color is. Blue, black or purple structural paints reflect just as much heat as bright whites or beige. This opens the door for more colorful, cooler architecture and design without having to worry about the heat.

It's not just cleaner, Chanda said. Structural paint weighs much less than pigmented paint and doesn't fade over time like traditional pigments. "A raisin's worth of structural paint is enough to cover the front and back of a door," he said. Unlike pigments which rely on layers of pigment to achieve depth of color, structural paint only requires one thin layer of particles to fully cover a surface in color. This means that structural paint could be a boon for aerospace engineers who rely on the lowest weight possible to achieve higher fuel efficiency. The possibilities for structural paint are endless and Chanda hopes that cans of structural paint will soon be available in hardware stores.
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Scientists Create Eco-Friendly Paint That Keeps the Surface Beneath Cool

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  • Do 747s need to be painted at all ?
    • Yes. The company I work for owns a bunch of patents for various clever pigments that save airlines millions every year due to how their planes get painted.
      If these researchers have what they say they've got, we'll make them very, very rich.
      • Re:painting 747s (Score:5, Insightful)

        by TWX ( 665546 ) on Thursday April 13, 2023 @11:02PM (#63448502)

        Pedantically aluminum aircraft fuselages don't need to be painted, they can be polished instead.

        But polishing the aircraft so it doesn't get chalky and dull, which is an issue for aluminum, is more labor-intensive than just painting the aircraft. They still require some cleaning, but not to the extent of polishing.

        As for these researchers' developments, I want to see information on durability. In many industries they talk about coatings rather than paints, because the coatings usually serve other functions besides appearance, such as corrosion protection. It's all fine that they've managed to figure out how to reflect infrared, but if these paints don't provide the other benefits that existing products offer then it may still be necessary to apply those coatings, before using this product as a top-coat. That still means at least a two-stage process.

        • Anodization is still a thing. It produces a durable finish and isn't labor intensive like polishing. You just wouldn't be able to change the appearance on a whim.
          • by TWX ( 665546 )

            If you can point to an example of a commercial passenger liner whose fuselage has been anodized I'd like to see that.

          • by smap77 ( 1022907 )

            It would look like a patchwork quilt. The alloys are probably all wrong for the dye as well.

            Unless you are thinking of building the entire plane and then anodizing it all at one time in a giant tank? YMMV.

            • And? Why does it need to be particularly attractive?
              • From my understanding, commercial aircraft are painted for branding reasons, as well as protection form the elements. Branding is reason number one for our customers.
      • A thin layer may be colorful, but it will scratch extremely easily. One flight and it would need to be reapplied unless coated over, which may defeat the purpose.
  • by Spamalope ( 91802 ) on Thursday April 13, 2023 @10:15PM (#63448396)
    Here is a link to the video. His whole channel is worth watching. https://youtu.be/dNs_kNilSjk [youtu.be]
    • I haven't watched in depth yet but it's just impossible claim after impossible claim in the titles.

      Color me skeptical.

    • Nope. That's barium sulfate. A novel pigment, but not structural color, like this article. The latter is responsible for things like blue morpho butterfly wings, opal, etc.

  • by awwshit ( 6214476 ) on Thursday April 13, 2023 @10:32PM (#63448424)

    You go Florida Man.

  • We've known about this method of colour creation for as long as I can recall. Insects use it, and peacocks, and probably a host of other creatures I can't remember. Point is, it's a known thing.

    What is new here is the 'self-assembly' manufacturing technique that makes it commercially viable to produce.

    • by TWX ( 665546 )

      Of course. Iridescence has been long studied. But the infrared portion seems to be new.

    • We've known about this method of colour creation for as long as I can recall. Insects use it, and peacocks, and probably a host of other creatures I can't remember.

      Yes. If you read the article, they even mention that. This, however, is the first time someone has figured out a way to actually DO it. If a way can be determined to make this cheaply, this is a game changer. One drop of this stuff is enough to paint a door (both sides). The weight savings alone on aircraft will be HUGE. Imagine the exterior of a building or a house painted with this, roofing shingles that get their color from this, heck, even a clear coating that just reflects infrared on car/h

      • by gweihir ( 88907 )

        Indeed. That is if they can make it cheaply and assure good properties regarding its nature as paint.

      • >This, however, is the first time someone has figured out a way to actually DO it.

        Yes, if you read my post, I even mention that.

  • I see this work was funded by our taxes via the National Science Foundation. So I'm sure the university and its researchers won't attempt to patent and monetize it!

    • Re: (Score:2, Informative)

      by Anonymous Coward

      Since the 1980 enactment of the Bayh-Dole Act, the federal government has allowed universities and other nonprofit organizations to patent and retain title to inventions created from research funded by the government.

      Universities, in turn, must:
      * offer to license the rights to innovations to industry;
      * use any remaining income, minus the costs of technology management expenses, for scientific research or education;
      * share any future income from the patent with the inventor; and

    • What's wrong with commercializing (monetizing) that? There are two scenarios: they don't protect it with IP so the major paint companies run with it, or they do protect it with IP, and then the university/researchers commercialize it themselves. Either way it gets commercialized and someone makes $$$. If this is a valuable technology, those are the mechanisms by which it ends up back in taxpayer hands.

      You could argue that the government should get repaid, but the NSF and other funding agencies aren't VC in

  • If I paint myself with this, will I finally be cool?

  • Had problems because of the blue color
    https://simpleflying.com/air-f... [simpleflying.com]

  • Durable? (Score:4, Insightful)

    by MancunianMaskMan ( 701642 ) on Friday April 14, 2023 @07:53AM (#63449010)
    structural colour, how resistant to abrasion and contamination is it? Parrots and butterflies preen themselves a fair bit, and the former replace their feathers regularly, while the latter are famously fragile and relatively short-lived.
  • And will it stick to vinyl, or would I have to replace the siding? It's all well and good to say that it only takes a thin layer of particles and that a raisin's worth will do two doors, but how do you get it on them?
    • Apparently it would go on much like regular paint.

      "we formulated a paint by mixing the structural color flakes with a drying oil (linseed oil, Gamblin) (Fig. 6A). The mixture presents the simplest form of a paint, where the flakes are the pigment and the oil is the binder that permits transferring to the target substrate. This mixture can be used then to coat surfaces in applications otherwise incompatible with vacuum systems. In Fig. 6B, we show such an example, where we painted an artistic multicolor butt

    • It's like any other paint, with particles of pigment in a binder like oil. The big difference is that the particles are super-thin flakes that still manage to be perfectly opaque because of their structure. When laid flat on a surface, you can't see through it no matter how thin the layer of particles is.

      Regular paint needs to have macroscopic thickness or it'll be transparent. It's like, a certain percentage of light of a given wavelength is absorbed as it travels through each micrometer of paint thickness

  • Eh, paint a whole house with it.
  • "A raisin's worth" shall now be added to the pantheon of plebeian units of measure along with "football fields"

  • Their paint requires aluminum nano-particles to not oxidize. They call out pigmented paints for fading, but I'm pretty sure this paint will fade too. Maybe even faster than regular paint. Noticeably absent from this article is a description of where this paint was used as actual paint and what the results were. Stainless steel nano-particles might be a better choice, maybe they are holding that back for the patent.
    • They use aluminum oxide which is already oxidized.... Here's a quote from the published content.

      Although aluminum, due to its native oxide layer, is very chemically stable in atmosphere, we found the structures to be fragile to harsh contaminants and physical contact. To address this, we capped the samples with a commercial polyurethane clear coat .

  • Where does that reflected IR go ?

    • It's not a perfect mirror, so it's diffused in random directions.

      If you want to see an example of a similar tech working, have a look at this video.

      https://youtu.be/dNs_kNilSjk?t... [youtu.be]

      It's Tech Ingredients, a very competent DIY-er comparing a metal plate painted with his homemade barium sulfate nanoparticle paint, bare aluminum, and white Rustoleum. TI's goal is to make passive heat radiators that not only reflect incoming IR but also have a high enough emissivity to negate what heat it does absorb and cool be

  • Nope (Score:4, Informative)

    by groobly ( 6155920 ) on Friday April 14, 2023 @01:59PM (#63449836)

    "Infrared light is the reason black cars get hot on sunny days and asphalt is hot to the touch in summer." Nope. It is BLACK because it is absorbing all VISIBLE wavelengths. In fact, it re-radiates in infrared. Yes, it also might or might not absorb infrared, but that is not THE reason.

    "sunlight at Earth's surface is around 52 to 55 percent infrared (above 700 nm), 42 to 43 percent visible (400 to 700 nm)," --wikipedia.

  • This is illegal according to a bill certain to be passed and signed by the Florida Governor. It would severely impact an important local industry.

  • If you ask me, this discovery is quite interesting but highly unpredictable and it will take a long time with real experiments for it to come into force. But it would be perfect for books and other works that fade with time. So my favorite book Perfume: The Story of a Murderer that I listened to on https://freebooksummary.com/category/perfume-the-story-of-a-murderer [freebooksummary.com] and then bought the paper version wouldn't fade like that. But this is just a prototype that has not yet come into use and we have to wait for

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