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Whitest paint is now thin enough to coat cars and planes
- Ancalagon 4y agoVery cool, but im skeptical about cost
- adrian_b 4y agoWith less than 300 grams of paint per square meter and a pigment made from cheap ingredients, it is unlikely to be more expensive than titanium white, but obviously this will be true only if it will be produced in large enough quantities.
- Ancalagon 4y agoYeah I mean I think all comes down to scalability not necessarily raw materials.
- JoeAltmaier 4y agoIt's things like this that have the potential to have big effects. Savings to cooling will directly improve energy efficiency and thus CO2 production.
- gonz0p0litik 4y ago
- colanderman 4y agoYes, it goes somewhere where we don't feel the need to spend energy moving it away from.
- gonz0p0litik 4y ago
- jrockway 4y agoI would assume that cooling buildings is more efficient than cooling small cars and planes. Buildings can, for example, use a ground source heat pump, which isn't an option for vehicles. I also have to assume that a perfect reflection from the top of a car or a plane just sends the radiation out into space.
- colanderman 4y agoBuildings subtend a very small solid angle relative to the earth and the sky most anywhere I drive (and I live in a major metropolitan area).
- wffurr 4y agoBack into space. Seems fine.
- njdvndsjkvn 4y agoBack towards space is more accurate. Some of the light will bounce back to the earth because of the greenhouse effect. edit: This doesn't mean that the paint isn't effective for what the researchers want it to do, in case that wasn't clear
- ceejayoz 4y ago> Reflected heat has to go somewhere. Back out to space, where it came from.
- metadat 4y agoHow does this new paint compare to the contents of a spray paint can from Home Depot? Having a hard time searching the web for this one, the first few pages of hits are all about this new 98.1% paint.
- zmgsabst 4y agoYou’re looking for something called “light reflectance value” or LRV. You can get 90-94% in wall paints; not sure about spray paints. https://www.kylieminteriors.ca/paint-colour-review-the-5-whitest-white-paint-colours/ https://www.kylieminteriors.ca/paint-colour-review-the-5-whi...
- throwaway888abc 4y agoThanks both, great q/a
- RetpolineDrama 4y agoThe future is now, and it is blinding!
- crayboff 4y agoI know nothing about this sort of stuff, but if this were applied to cars, would there be an increased risk of temporarily blinding other drivers on a sunny day?
- aliqot 4y agoHow does it affect white balancing on traffic cameras?
- HPsquared 4y agoIt won't shine any brighter than the light that's hitting it.
- lpghatguy 4y agoLike... the sun?
- Dylan16807 4y agoNot like the sun. A white object is thousands of times less bright, because in every direction it emits an average of the light hitting it and the sun is such a small fraction of the sky.
- twawaaay 4y agoStill, snow can cause blindness: https://en.wikipedia.org/wiki/Photokeratitis https://en.wikipedia.org/wiki/Photokeratitis
- tlb 4y agoIt reflects something like 98% of light instead of 90%, so the actual increase in reflected light isn't that big. Flat scattering surfaces are never blinding. The problem is with specular reflections off of shiny surfaces. Even though a shiny surface may only reflect a small fraction of incident light, it's all pointing in one direction which can dazzle observers.
- 4y ago
- jamesgreenleaf 4y agoIf you mixed it with Vantablack, would you get the greyest possible paint? /s
- WallyFunk 4y agoYou could try buying some and find out! https://culturehustle.com/products/black-v1-0-beta-the-world-s-mattest-flattest-blackest-art-material https://culturehustle.com/products/black-v1-0-beta-the-world... You could also mix it with the 'whitest white' https://culturehustle.com/products/white-20 https://culturehustle.com/products/white-20
- dfxm12 4y agoYou linked to black 2.0. It may very well be the blackest black, but it is decidedly not Vantablack. I think this is worth distinguishing, because interestingly, I don't think just anyone can get their hands on Vantablack because someone obtained exclusive rights to it. :) https://en.wikipedia.org/wiki/Stuart_Semple#Conflict_with_Anish_Kapoor https://en.wikipedia.org/wiki/Stuart_Semple#Conflict_with_An...
- olliej 4y agoMany years ago I bought some of the black 2.0 on a lark, and honestly both brush and air brushing seemed to produce very meh results. Like nothing that to me indicated any significant difference in matteness vs many other paints I’ve used. Now I realize I didn’t try applying it to actual glass or anything, but even on polished resin it didn’t stand out as meaningfully different. Vanta black is a whole different beast, but it also isn’t paint so I feel it’s cheating that particular race :)
- Doxin 4y agoIn my experience black 2.0 is pretty dang black, but it's not nearly as black as the marketing photos make it seem. It's still plainly visible in daylight. It's a structural black too, so in general touching it will make it more gray. Still an amazing product for all sorts of art, but also for building telescopes or photography hardware.
- daveslash 4y agoRe >> "with an ability to reflect around 98% of incoming sunlight" Seems like a mirror would reflect even more light. Now, obviously we don't want to make the exteriors of our buildings and cars a mirror!. but it made me wonder: What's the difference between a really really really white paint that reflects 98%+ light, vs. a reflective surface? Is it that the white paint reflects the light, but in a "scrambled" form, thus losing the image?
- wffurr 4y agoYes, it's not reflecting the light so much as re-radiating it in a diffuse pattern.
- thehappypm 4y agoI don’t think there’s a physical difference between reflection and re-radiation, is there? Reflection is just highly organized/non-diffuse.
- Fronzie 4y agoreflection is coherent, a single physical process. The light keeps it's phase and polarization. Re-radiation is incoherent, caused by multiple particle interactions (physical processes). So there's quite a difference in physics.
- thehappypm 4y agoCan you explain? As I understand it, in both cases, a photon comes in, gets absorbed by the material, and then gets re emitted.
- njdvndsjkvn 4y agoyes. A white surface scatters the photons and a reflective one keeps them in the same position relative to the others. If you make a surface smooth enough it starts becoming partly reflective. There is also scattering of photons that happens in object itself I found this video about the topic to be interesting: https://www.youtube.com/watch?v=1n_otIs6z6E https://www.youtube.com/watch?v=1n_otIs6z6E (title: Why aren't Mirrors White? Why isn't EVERYTHING a Mirror?)
- tobyjsullivan 4y ago> The new material features boron nitride in hexagonal nanoplatelet form and offers a solar reflectance of 97.9% What's the difference between white paint and a mirror? Scatter?
- zmgsabst 4y agoYep — mirrors are coherent while white paints scatter, even though they reflect similar amounts of light.
- colanderman 4y agoYes, exactly.
- theandrewbailey 4y agoIf this takes over and is used everywhere, in 50 years, will people become nostalgic over titanium dioxide white? Will the titanium industry be supported by the few remaining vintage white paint manufacturers? \s
- twawaaay 4y agoI think people will in fact get nostalgic about titanium dioxide white. Actually any white. Looking at the progress, in 50 years every surface is going to be covered with ads.
- bilsbie 4y agoCouldn’t this be revolutionary for spacecraft? Also would it make a better solar sail?
- detritus 4y agoColour me stupid, but in a simple white vs. black comparison, wouldn't a VantaBlack-clad solar sail absorb more energy, so be more useful? - ed I'm misunderestimating 'equal and opposite' photon reflections here, aren't I?
- twawaaay 4y agoFor solar sail you don't want to absorb, you want to reflect. When you absorb you only get half of the push (assuming reflective surface reflecting directly back at 100% efficiency vs absorbed heat that gets radiated omnidirectionally).
- thehappypm 4y agoIf you’re harvesting the energy from photons into heat, you’d want black. Any photon hitting your sail would be absorbed, and give you its momentum and energy. If you’re harvesting the momentum from a photon into momentum for your spaceship, you’re better off with white. A photon being reflected gives you its momentum twice. It’s first (briefly) caught like the black sail, imparting its momentum, but then it’s re emitted and hurled away, like a cannon, giving even more reactive momentum to the sail
- c7b 4y agoAre airplanes more in need of cooling or heating? The outside temperature at cruising altitude is around -50° (roughly where the Celsius and Fahrenheit scales meet, btw), is the insulation good enough to just keep the inside at acceptable temperatures for humans?
- deleted 4y ago[deleted]
- twawaaay 4y agoIt does not matter for airplanes. Both cooling and heating are in ample supply on an airplane.
- dingaling 4y agoCooling is in short supply when the aeroplane is parked on the ground. In some climates external air conditioning units are required to maintain a manageable cabin temperature. Hence why the majority of airline fleets have white-painted upper fuselages.
- chuzz 4y agoThe article mentions airplanes waiting on the ground, but I do wonder what happens during flight. I suppose the engines create plenty of heat after all.
- crazygringo 4y agoI know white clothing often contains "brighteners" which fluoresce, converting received UV light into visible wavelengths, so the resulting white is brighter than what is reflected in the visible spectrum. I'm just curious what role that ever plays in paint, if this 98% reflectivity is a big deal, or if we already have white paint with over 100% because of brighteners.
- adrian_b 4y agoThis 98% reflectivity refers to the total solar light, including infrared and ultraviolet light, because the purpose is to cool whatever is painted, despite being illuminated by the Sun. With fluorescent paints, the energy of the emitted visible light is always less than the energy of the absorbed ultraviolet light. The difference is heat that warms the paint. The paints discussed in the article also reflect the ultraviolet light. Moreover, they also emit infrared light in the frequency band where the air is transparent, and that infrared light leaves the Earth if the painted object is outdoors, which will be true for a building or for a car while it is used. By emitting more energy than it is absorbed from the solar light, the painted object is cooled (if it is outdoors).
- chris_st 4y agoFinally, we can make the city in Mirror's Edge [1] into reality! 1 https://en.wikipedia.org/wiki/Mirror%27s_Edge https://en.wikipedia.org/wiki/Mirror%27s_Edge
- ahazred8ta 4y agoBoron nitride and barium sulfate pigment.
- bilsbie 4y agoThis would be really cool for a shirt or hat.
- djmips 4y agoSurfaces get dirty in the real world. Won't these fantastic figures degrade rather quickly?
- adrian_b 4y agoWhile I find it very interesting that boron nitride can outperform all other white pigments in the combination between total solar reflectance and layer thickness, I believe that an another approach for making a white paint is even more promising. That method is described in the reference #17 from the bibliography of this paper. There are 2 methods that can be used to make a white paint. The first is to use a polymer as a binder and incorporate in it very small particles with high refractive index, i.e. a white pigment powder. The second method is to make a polymer that solidifies as a foam. In this case, the polymer contains voids filled with air having low refractive index, instead of pigment particles, but the effect of the optical non-homogeneity is the same, so both foams and powders are white, when they do not absorb light. The reference #17 describes such a method of making a polymeric foam, which can be used as a paint. According to the table from this paper about boron nitride, the previous best combination of total solar reflectance and layer thickness and layer density was for that polymeric foam, which had a 96% total solar reflectance and a 300 micron thickness, outperforming all the previous paints based on white pigments. While that foam had a slightly lower total solar reflectance, it had a better far infrared emittance, so the cooling performance was similar, i.e. of about 6 Celsius degrees below the air temperature. Because the methods that use foams do not need pigments, they have the potential to be cheaper than the methods with pigments, which need both a polymer as binder and a mineral pigment. Moreover, methods to make foams can be adapted to many different kinds of polymers, so there are chances that other polymers with even better performances or even lower cost can be found, perhaps a silicone polymer in foam form (silicones can have perfect resistance to solar light in outdoor conditions).
- foxyv 4y agoI wonder what difference a metal roof would make temperature wise to have this stuff on it in broad daylight?