Solar reflective coatings with luminescence and self-cleaning function

Abstract

In this work, hydrophobic nano-silica, titanium dioxide powder, and luminous powder were simultaneously introduced into polydimethylsiloxane (PDMS), and a multifunctional coating was obtained using a simple brush-coating method. The solar reflectivity of the coating was studied, in which the near-infrared reflection and solar reflection values are 0.813 and 0.826 respectively, which have an obvious cooling effect on ordinary cement board. The coating exhibits superhyophobicity, with a contact angle (CA) of 155.2° and a sliding angle (SA) of 5.8°. In addition, the coating is mechanically robust and chemically resistant. It can still maintain superhydrophobic effect after being dragged 2 m under 1.0 kPa pressure, and the water droplets with different pH can also maintain superhydrophobic state. Meanwhile, the coating can remain superhydrophobicity after 10 times of of cooling/heating (-25°C - 100°C) cycles or 200 h UV aging test. As a result, the coatings have excellent durability in everyday life. The maximum continuous luminescence time of the coating can reach about 3.2 h with wonderful decorative effect. Therefore, the superhydrophobic luminescent coating with simple preparation technology, good decorative effect and excellent durability has a great application prospect.