The bilayer coating stays cooler under sunglight. Source: Jyotirmoy MandalResearchers from Howard University (Washington D.C.), Peking University (China) and Columbia University (New York) have created a double-layered paint capable of reflecting heat without reflecting glare.

The researchers developed the dual layer paint with the aim of capturing the heat reflecting properties of white (or silver) paint without the glare to improve the efficiency of buildings in tropical climates.

As such, the bottom layer of the paint, the side that is in contact with the surface of a building, is a 500 micrometers-thick porous material like Teflon that reflects light, and, consequently, heat, from buildings, and features a network of micro- and nanopores.

Meanwhile, the top coat, which is the visible coat, is similar to traditional paint, absorbing specific wavelengths of light, thereby making the paint appear as specific colors beyond the heat reflecting white and the darker, heat absorbing colors associated with increased air conditioning bills. This layer opens up the possibility of different colors for the exterior of buildings.

During testing of the paint, researchers determined that an object painted black — the color most closely associated with heat absorption — had an internal temperature that was 16° C cooler than an object not treated with the dual layer paint.

With the potential for cooling buildings in desert and tropical locations, the research team is exploring how to eventually capture the heat reflected by the paint to harvest electricity.

The research appears in the journal Science Advances.