Study of a super-non-wetting self-cleaning solar reflective blue-grey paint coating with luminescence

A method for generating a solar reflective blue-grey paint coating with yellow-green luminescence that is cost-effective, industrially scalable, widely applicable, easily repairable, super-non-wetting, self-cleaning, and solar reflective, is introduced. The coating can be manufactured using as-received commercially available materials and following a simple industrial procedure. Grinding the coating surfaces using emery papers with appropriate grit numbers can readily yield appropriate surface roughness, generate suitable micro-grooves and expose micro- and nano-particles on the coating surfaces, thus endowing the coating surfaces with super-non-wettability and self-cleaning property. The surface free energy of the coating only depends on the dispersive component and both the Lewis acid component and the Lewis base component are 0 mN/m. The solar reflective blue-grey coating with solar reflectance of 0.808 can yield a cooling effect of 22.6 °C relative to a flat or low-sloped concrete roof on a typical clear summer sunny day. It emits yellow-green luminescence during the night, thus decorating the buildings to some extent when applied to the external walls of buildings. Although the super-non-wettability of the coating surfaces might be destroyed mainly by the periodic spraying of water (simulated by 400 h of artificial accelerated weathering tests), the super-non-wettability and the self-cleaning property can be completely re-established after roughening the weathered coating surfaces using emery papers with appropriate grit numbers. In terms of optical properties, the solar reflective blue-grey coating with yellow-green luminescence has good resistance to artificial accelerated weathering.