Robust superhydrophobic composite fabricated by a dual-sized particle design

Superhydrophobic surfaces have shown great potential in various areas such as self-cleaning, anti-icing, drag reduction and biomedical applications. However, it is still challenging to prepare robust superhydrophobic surfaces for real applications. Here, a facile, low-cost dual-sized particle strategy is proposed to fabricate the robust superhydrophobic composite with an “armoured” micro-/nanostructure. As a proof-of-concept, the intrinsically hard quartz sand microparticles (QS MPs) and the epoxy (EP) adhesive are adopted to construct a firm surface frame (EP@QS) as an “armour” to provide mechanical durability while modified superhydrophobic SiO2 nanoparticles (msSiO2 NPs) are confined within the cavities among the QS MPs, forming a nanostructure to impart liquid repellency. Benefitting from the strong “armour”, the EP@QS@msSiO2 composite can reserve excellent water repellency after different kinds of environmental test such as cycled mechanical abrasion, ultraviolet radiation treatment, outdoor exposure damage, tape-stripping test, acid-base treatment and NaCl salt solution immersion, temperature treatment and knife scratching. Furthermore, the substrate versatility and nanoparticle versatility of our strategy are explored and verified. By virtue of the structural advantages, these EP@QS@msSiO2 composite manifest superior self-cleaning property and efficiently directional oil adsorption ability even after mechanochemical damage. Together with robustness and universality, the design strategy of the robust superhydrophobic composite is expected to extend the application scope in harsh nautical applications.