A team of Harvard engineers are developing a way of producing colour that could produce paint that never fades, and displays that never go dark.
Believe it or not, the method is based on bird feathers, which last centuries without losing their bright hues. This is because of how their colours are formed. Unlike your T-shirt or a painting on the wall, feathers don't get their colour from pigments that absorb certain wavelengths and reflect the rest. "What that means is that the material is absorbing some energy, and that means that over time, the material will fade," says Vinothan N. Manoharan, a researcher at Harvard's School of Engineering and Applied Science who's leading the effort.
Bird feathers, by contrast, stay bright because their feathers contain nanostructures that amplify specific wavelengths of light; it's called structural colour. Basically, the feathers' cells contain a series of tiny pores spaced in such a way that they only reflect, for instance, shades of red. Manoharan's team is recreating this effect in the lab by using microparticles suspended in a solution. When the solution dries out, the microparticles shrink and bring the particles closer together. And depending on how much of the solution dries out, the distance between the particles causes them to reflect different wavelengths of colour. The effect will even work with pixels on a display.
It's a little hard to wrap your head around, but this graphic might help. The red microcapsule starts out large on the left and shrinks as it dries out, producing shades of orange, yellow, and green:
"We think it could be possible to create a full-colour display that won't fade over time," says Manoharan. "The dream is that you could have a piece of flexible plastic that you can put graphics on in full colour and read in bright sunlight." Paint and ink that never fade are also a possibility.
For now, the development of such a display or paint is in the early, experimental stages. But imagine opening a laptop in bright sunlight and seeing the same vibrant colours you'd see in a magazine. With these advancements that is an idea just waiting to be realised. [Harvard]