Abstract:In this work，a simple and effective approach was reported to fabricate a low-cost, environment-friendly, self-cleaning and mechanically durable superhydrophobic film. The film was prepared by dip-coating acrylic resin film in an ethanol/ethyl acetate suspension of SiO2 and hexamethylene diisocyanate trimer (HDI trimer). Since the solubility of acrylic resin in ethyl acetate (solvent) differs from in ethanol (non-solvent), a porous structure was formed on the film surface based on phase separation. SEM images showed that as the volume ratio of ethyl acetate in mixture increased, the coated surfaces became fluffier and internal pores were larger. By contrast, the porous structures were more uniform and complete when the volume ratio of ethanol to ethyl acetate reached 6∶4 in solvent mixture. With a further addition of SiO2, the hydrophobicity of the film was greatly enhanced. Porous structures were also observed after SiO2 was added, and more nanoparticles were deposited on the inner wall of the holes as the content of SiO2 increased, which helped to form a dense nanoscale layer during phase separation process. The synergistic effect of nanoscale SiO2 and microscopic holes endowed the film with a remarkable superhydrophobicity (158° ± 3°) and self-cleaning property when 2.5 g of SiO2 was added. Moreover, acrylic resin and SiO2 were further cured by HDI trimer through the reaction between isocyanate groups and hydroxyl groups, which improved the mechanical properties of the superhydrophobic film. The performance test showed that the film still kept its superhydrophobicity after 35 cycles of sandpaper abrasion under 100 g of loading, indicating a pretty admirable mechanical durability. The facile preparation and high-performance of the superhydrophobic film make it quite suitable for the manufacture in a large scale, which would have extensive application prospects in the future.