Materials

Super white paint leans on Teflon to reflect up to 98% of the Sun's heat

Super white paint leans on Tef...
Whereas traditional white paints typically reflect around 85% of solar radiation to help keep buildings cool, a new "super white" paint can reflect up to 98%
Whereas traditional white paints typically reflect around 85% of solar radiation to help keep buildings cool, a new "super white" paint can reflect up to 98%
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Whereas traditional white paints typically reflect around 85% of solar radiation to help keep buildings cool, a new "super white" paint can reflect up to 98%
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Whereas traditional white paints typically reflect around 85% of solar radiation to help keep buildings cool, a new "super white" paint can reflect up to 98%
Effectiveness of the new super white paint (labeled E1 and E3) compared to current paints (E2)
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Effectiveness of the new super white paint (labeled E1 and E3) compared to current paints (E2)

Just like a tennis player might don a white shirt instead of a black one on warm summer's day, researchers see great potential in dressing buildings in reflective white paints to keep them cool. A team of material scientists is reporting a major advance in this area, producing a new kind of super white paint that reflects almost all incoming radiation from Sun.

For some time, scientists have been exploring how broad use of white paint could significantly cool buildings, and even the surrounding microclimate. One NASA study from 2012, for example, found that white coatings could reduce peak rooftop temperatures in New York City by an average of 43 °F (24 °C).

While researchers continue to probe the possibilities in this area, with some even producing reflective paint made from glass, the best performing white paints on the market reflect about 85 percent of solar radiation, while absorbing the rest. The team from the University of California, Los Angeles (UCLA) hoped to improve on this by making a few tweaks to the recipe.

The key ingredient in current cooling white paints is titanium oxide, which is very effective at reflecting the majority of visible and near-infrared light. One shortcoming, however, is that it absorbs ultraviolet and violet light at the same time, which leaves some room for improvement.

Through their explorations of alternative materials, the team found success in substituting titanium oxide for an artist’s pigment called barite, along with Teflon, or polytetrafluoroethylene. The scientists also cut down on the number of polymer binders in the paint, which usually serve to absorb heat.

Effectiveness of the new super white paint (labeled E1 and E3) compared to current paints (E2)
Effectiveness of the new super white paint (labeled E1 and E3) compared to current paints (E2)

These changes to the recipe resulted in a super white paint with significantly improved cooling capabilities, so much so that it was shown to reflect up to 98 percent of incoming radiation during testing. This kind of material could play a big role in cutting down the cooling costs of buildings, by reducing the use of air conditioners and other systems. And the team says it shouldn’t take too much work to deploy it in real-world scenarios.

“The potential cooling benefits this can yield may be realized in the near future because the modifications we propose are within the capabilities of the paint and coatings industry,” says UCLA postdoctoral scholar Jyotirmoy Mandal.

The research was published in the journal Joule.

Source: University of California, Los Angeles

14 comments
HahaDaJoker
Teflon is also very toxic. Remember lead paint? What happens when this paint dries and chips off? It will get ingested one way or another. Watch that movie "Dark waters" (?) with mark ruffalo in it
michael_dowling
HahaDaJoker: No,you are wrong. Teflon is stable and nontoxic unless heated to it's breakdown temperature of 500 Fahrenheit. Flakes from your frypan will pass through your gut harmlessly. Lead is a totally different animal.
moreover
Another use case: under bifacial solar panels. Also, most industrial buildings with flat roofs these days use a thick white roofing material off a roll that is impenetrable and long lasting. All the better if coated with this highly reflective paint.
CraigAllenCorson
There is a good reason that one often sees buildings in hot climates painted in light pastel colors. They tried white, and found it to be blinding when walking through the streets. This new whiter white will be even more so. When it comes down to a choice between saving on cooling costs or saving eyesight, guess which choice most people will make?
Mik Fielding
All very well, but polluting the environment with polytetrafluoroethylene is far worse than any good it may possibly do. With the quantities potentially involved it could well be catastrophic!

It will breakdown through friction from winds and rain etc. It is certainly not non-toxic and there is plenty of evidence for that.
Like micro-plastics it would become yet another synthetic material added to the environment in the form of tiny particles.

These developers really need to get their heads out of their behinds and do a bit of basic research!
BlueOak
The Teflon wouldn’t bother me one bit since it isn’t being super-heated above frypan temps required to make it toxic. However, “The scientists also cut down on the number of polymer binders in the paint” makes one wonder whether the resulting paint will have the durability of boat bottom paint and need to be recoated every several years.
ADVENTUREMUFFINffin
Nick, in order to give a balanced report, please check the fact on PFOA. https://www.cancer.org/cancer/cancer-causes/teflon-and-perfluorooctanoic-acid-pfoa.html
Giving a critical review of stupid ideas like this, that damage the environment and humans more than they help, is a critical thinking skill that we need to hear. Otherwise, you become a shrill for industry. The popular movie "Dark Waters" could help raise your awareness of the importance of demonstrating products are safe before they can be marketed.
Gregg Eshelman
Teflon can cause a lot of damage in the body. When used in joint replacement and repair parts it failed under load, shedding particles which the immune system attempted to deal with in a self destructive fashion. Some people with TMJ implants with Teflon ended up with holes in their skulls. https://curvolabs.com/insights/tmj-implants-lessons-for-all-of-us/ For uses where the Teflon isn't subjected to mechanical loads, it stays together and is very bio compatible.
GordonHoffman
98% full spectrum reflectivity is great - as good as highly polished aluminum. One could make some great reflectors for a solar oven, using cardboard and a coating. I am currently using some old fiberglass greenhouse glazing material with a space heating blanket to bake weeds to death in my driveway. I hope it is not toxic, and not too expensive.
HahaDaJoker
Michael dowling: No, teflon and pfoa's are toxic even when not in a frying pan and even when cold.

https://www.motherjones.com/environment/2007/05/teflon-forever/