Scientists accidentally create the world's lightest paint by mimicking Mother Nature

Cal Jeffrey

Posts: 3,859   +1,237
Staff member
Yeah! Science! Traditional paint is made from a bonding agent, such as oil, and pigments from heavy metals like cobalt, ochre, and cadmium, which make blue, red, and yellow, respectively. We use paint to color the artificial world, but in nature, creatures such as butterflies and beetles display vibrant palettes without pigment – they use topography.

Take a peacock feather, for example. Submicroscopic ridges and contours in a peacock feather diffract light to create the iridescent blues and greens we see. This natural coloring is called structural color.

Scientists at the University of Central Florida have developed a "first-of-a-kind" paint that mimics the structural coloring we see in nature. Debashis Chanda, co-author of the study, "Ultralight plasmonic structural color paint," and his team accidentally stumbled upon the discovery.

The initial goal was to make a long continuous aluminum mirror using an electron beam evaporator. However, after numerous failed attempts, they noticed that the aluminum clumped together, creating microscopic "nanoislands." The bunching prevented the mirror from developing the highly reflective surface needed for a mirror. Chanda said, "It was really annoying."

However, he noticed that the aluminum's electrons became agitated when ambient light hit the nanoparticles, causing them to oscillate. Furthermore, the electrons resonated with various wavelengths of light depending on the nanoparticle size. White light hitting the uneven surface bounced around its ridges before finally reflecting as a single color.

"Just by shifting the dimension[s of the nanoparticles], you can actually create all colors," Chanda told Wired.

So the team began working to create various colors of paint by growing aluminum nanoislands in a double-sided mirror, then specifically "dissolved" sheets of them into dust the consistency of powdered sugar. They then mixed the various colored materials with binders to make paint.

Chanda said that because of its structural nature, only a very thin coat is needed to color a surface. He says a drop the size of a raisin can paint both sides of a door. This property makes it ultralight, which could be extremely helpful in the airline industry.

A Boeing 747 requires about 1,000 pounds of paint. Chanda estimates it would take less than three pounds of his team's structural color to coat a jet, shaving over 997 pounds. It might not seem significant for a craft that weighs just south of a million pounds. However, just saving a little weight translates to massive savings in fuel.

"Given that fuel is already the single biggest operating expense [about 30 percent last year], airlines are always interested in improving fuel efficiency," said a spokesperson for for the International Airline Trade Association.

For example, American Airlines estimated that it saved 400,000 gallons of fuel and $1.2 million annually by removing only 67 pounds of pilot manuals from its planes. The company claims it saved another 300,000 gallons in 2021 by switching to a lighter paint that shed 62 pounds from its 737s.

Another advantage of this type of paint is its durability. Airlines repaint their planes up to four times a year because of the sun's oxidation effects. Structural colors don't fade in the sun, meaning repainting is only needed when you want to change colors.

One final property of the paint makes it helpful in keeping things cooler. Most planes are white to reflect as much light as possible. Absorbed infrared radiation becomes trapped, making the interior warmer.

Preliminary tests show that the team's colorant keeps surface temperatures 20-30 degrees Fahrenheit cooler than traditional paint, regardless of the color. It's ideal for painting planes, cars, houses, and other buildings. If it can cut interior temperatures by even 15 degrees, it saves massive amounts of energy used for air conditioning.

The only problem the researchers face now is scalability. They have the equipment to make small vials but would have to produce much more to commercialize realistically. The lab is seeking commercial partners to help bring the paint to market.

Image credit: United Soybean Board

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m4a4

Posts: 3,331   +4,543
TechSpot Elite
A Boeing 747 requires about 1,000 pounds of paint. Chanda estimates it would take less than three pounds of his team's structural color to coat a jet, shaving over 997 pounds. It might not seem significant for a craft that weighs just south of a million pounds. However, just saving a little weight translates to massive savings in fuel.
But how much is the coating actually there for colour? I'm pretty sure it's more for protection against the elements (beyond sun bleaching) over making it look pretty.

I'm sure it'll still help (instead of using traditional colouring), but not as much as it sounds like...
 

Cal Jeffrey

Posts: 3,859   +1,237
Staff member
But how much is the coating actually there for colour? I'm pretty sure it's more for protection against the elements (beyond sun bleaching) over making it look pretty.

I'm sure it'll still help (instead of using traditional colouring), but not as much as it sounds like...
Yeah, I don't know. That was information provided by an International Airline Trade Association spokesman.
 

daffy duck

Posts: 140   +102
So they have basically discovered quantum dots. Nonparticles that can create different wavelengths based on their size.

BTW as someone that worked on structural colour in butterflies the term topography has never ever been used in this field.
 

mbk34

Posts: 516   +431
Out of curiosity, how do you apply a raisin sized drop of paint to something the size of a 737? I'm guessing very small paint brushes won't cut it.
 

Uncle Al

Posts: 9,576   +8,876
We keep hearing about these fabulous paints like the one that completely repels dirt and grime, but they never seem to make it into the marketplace .....
 

captaincranky

Posts: 19,397   +8,529
Structural colors don't fade in the sun, meaning repainting is only needed when you want to change colors.
OK, I call bullsh!t on the whole topic. "Chandra claims", "the company claims", bah humbug. Aircraft in the real world, face a harsh reality. High speed winds, heating and cooling cycles, rain, snow and ice, all tell me the the thinner the coating, the sooner it will wear off.

DuPont used to market a catalyzed acrylic enamel specifically designed for aviation named, "Imron". The extra heavy duty hardener was loaded with polyisocyanate, so as to retain flexibility, far beyond what was necessary in standard automotive acrylics

While paint technology may have advanced since then, you can't tell me that a finish a few microns thick is going to stay on a commercial airliner for very long.
 

Avro Arrow

Posts: 3,714   +4,802
This sounds promising in theory but as others have stated, there's no way that it can withstand the hellish environment that is the skin of an aircraft in flight. As an interior paint, however, it could work.

The only question I have is, if a drop the size of a raisin can paint both sides of a door, just how much will they try to gouge us for said raisin-sized drop?
 

HyperPete

Posts: 127   +63
I would like to know how to apply this said "paint". A raisin sized drop to paint my door will require 4 ounces to wet a roller, or 1 - 2 ounces to wet a paintbrush. This sounds a bit wasteful to me.
Even if it is sold in special spray cans, the amount adhering to the inside of the can, or that cannot be sprayed due to low volume, will far exceed the amount needed for a typical application.
 

p51d007

Posts: 3,541   +3,307
Of course "airlines", if this paint actually works, instead of reaping the savings in weight, and savings in fuel,
will just DECREASE the leg room on the plane even more, and stuff more seats into the cabin.
 
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Hodor

Posts: 765   +509
So they have basically discovered quantum dots. Nonparticles that can create different wavelengths based on their size.

Yeah, technology that many species of butterflies and other insects have developed millions of years ago. I guess the patent rights expired only this year.
 

captaincranky

Posts: 19,397   +8,529
The lab is seeking commercial partners to help bring the paint to market.
"To fund or not to fund, that is the question?" "Whether tis nobler in the mind to milk the fortune of another sucker, or pay for the scaling your damned self."

"(Captain Crankespeare)"

It's truly "miraculous" that aluminum portrays all these colors natively in teensy tiny blobs in the lab, but we haven't explained how we expect these particles to be non reactive to the atmosphere, with aluminum producing oxides, Which is after all, why you have to paint all exposed aluminum on an aircraft in the first place.

So, at the end of the day, it's practically a given that you'd have to clear coat the paint anyway. The same as we do with all metallic colors today. Oops, there goes the weight saving.
 

Robby-san

Posts: 14   +6
But how much is the coating actually there for colour? I'm pretty sure it's more for protection against the elements (beyond sun bleaching) over making it look pretty.

I'm sure it'll still help (instead of using traditional colouring), but not as much as it sounds like...
The colors the jets are painted are chosen to reflect sunlight and thereby keep heat out of the fuselage. They also, of course, help advertise, but the main purpose is reflection.
 

BadThad

Posts: 1,328   +1,602
Out of curiosity, how do you apply a raisin sized drop of paint to something the size of a 737? I'm guessing very small paint brushes won't cut it.

I think they're referring to the amount of "pigment" and not the total volume of paint.