Self-cleaning coating for exterior wall of concrete building

Abstract

Due to the advantages of beautiful appearance, the exterior wall real stone paint with properties of low-cost and good weather resistance has been widely applied in the concrete building for aesthetics and protection. However, the hydrophilicity of the exterior wall real stone paint make them susceptible to pollution by dust, acid rain, etc. Superhydrophobic coatings with the excellent self-cleaning property may effectively alleviate these problems, but the fabrication of the real stone paint coatings with superhydrophobicity has not been reported yet. Here, we developed a superhydrophobic exterior real stone paint coating (SEP-coating) with a water contact angle of 154 ± 3° and a rolling angle of 13 ± 2° by a simple and high-efficient physical blending method using emulsion, natural sand, low surface energy reagents and nano-SiO2. The SEP-coating possessed an excellent self-cleaning property for the pollutant including soil, dust and rust water, and had good anti-corrosion capability and outdoor time stability The SEP-coating also showed better solar reflectance characteristics than normal exterior real stone paint coating, which may contribute to lower temperatures in buildings during hot weather and save energy. In addition, a colorful SEP-coating for decorative requirements and large-area SEP-coating for practical application could be effectively fabricated, which is expected to have promising application prospects.