A melting pre-bonding method for fabrication of mechanical-robust superhydrophobic powder coatings

The rapid development of the coating industry has led to the exploration of novel functions beyond decoration and protection of traditional coatings. Superhydrophobic coatings bring about many potential benefits. e.g., water-repellency, self-cleaning property and corrosion resistance, etc. However, the durability of such coating remains an issue in the practical application. In the study, we proposed a melting pre-bonding method for synthesizing a durable solvent-free superhydrophobic powder coating with a high-water contact angle of 164.9°. With this method, the nano-micro polyester (PE)-SiO₂ conglomerates were formed, which involved compaction, heating, and grinding operations to bond the SiO₂ nanoparticles with the PE matrix. The resulting PE-5 %SiO₂/PE composite coating retain its high WCA of beyond 150° after 150 abrasion cycles, presenting excellent abrasion resistance. The coating also has exceptional self-cleaning property and water bouncing behavior, as well as long-term durability when exposed to strong/weak acid/base corrosion media, NaCl solution, and UV radiation. This melting pre-bonding method increases the dispersibility and stability of nanoparticles in the fabricated superhydrophobic coating film under high-temperature melt-curing process, which is beneficial in achieving improved mechanical durability compared to the regular direct-blending method. The work endows powder coating with superhydrophobic property, promoting the development of functional coatings.