Preparation of robust fluorine-free superhydrophobic coating using fly ash and its self-cleaning, anti-icing and anti-corrosion properties

Superhydrophobic coatings have attracted extensive interest from researchers in recent years. An important future development direction involves utilizing zero-cost solid waste materials as structural components to create superhydrophobic coatings. In this article, fly ash(FA), a common solid waste, was used as the main material, epoxy resin (ER) and polydimethylsiloxane (PDMS) were used as the main film-forming substances. A multifunctional FA-superhydrophobic coating ER/FA@PDMS/SiO 2 was prepared by spraying method. FA-superhydrophobic coating exhibited a water contact angle (WCA) of 156.4° ± 0.8° and water sliding angle (WSA) of 4.5° ± 0.1°. ER/FA primer has an irregular porous structure, and the PDMS/SiO 2 penetrate into the porous structure. The porous ER/FA coating can store PDMS and SiO 2 , and the FA superhydrophobic coating has similar rough structure and low surface energy inside and on the surface. FA-superhydrophobic coating have strong mechanical stability, after the surface coating is destroyed, the internal structure of the coating can still maintain excellent performance. The corrosion current density of FA-superhydrophobic coating is about 9.392 × 10 −7 A/cm 2 , which is one order of magnitude lower than ER/FA coating. FA-superhydrophobic coating can delay icing by about 121.55 % under extremely cold conditions. This simple and low-cost superhydrophobic coating has great application value in self-cleaning, anti-icing and anti-corrosion. • Preparation of FA superhydrophobic coatings by two-step spraying method • The coatings exhibit robust mechanical durability under harsh conditions. • Excellent anti-corrosion and anti-icing performances were achieved.