In many developed countries of the world, the use of external air conditioners to cool buildings or objects is impractical and too expensive – that is why many cover the facade and roofs of buildings with white paint in order to reflect as much light as possible. However, the traditional white paint, due to the presence of pigment, still is not so effective, since it absorbs most of the ultraviolet radiation. Therefore, experts from Columbia University decided to present their new development, which could potentially solve the problem of light reflection – and it consists in the use of special polymer paint.
They note that their polymer coating material does not contain paint pigments, but instead creates peculiar air pockets, due to which it is possible to effectively reflect ultraviolet light. Developers explain how their material works. This paint is created first with the organization of a special solution, which includes the polymer, solvent and water, with which the material as a whole is attached to the wall. And while the solvent evaporates in the sun, water forms small dense droplets inside the polymer – and when it comes to evaporate, a huge number of microscopic air pockets remain, creating a white color of polymer paint.
Specialists have already carried out preliminary tests of their new material and found that it reflects up to 96% of the sun's rays, allowing you to effectively protect the building or any other object from excessive heat in the sun.
And this is achieved due to the fact that due to the difference in the refractive index between the sun's rays and the polymer, these sun's rays efficiently spread across the entire surface of the polymer paint, thus changing the wavelength of the light in the process. Thus, experts found that by changing the density of the final polymer and controlling the rate of evaporation of water and solvent, they can achieve even more effective results – even when changing the color of the paint from white to any other.