Fabrication of superhydrophobic surface with hierarchical structure by thermal imprinting and spraying

Abstract

Superhydrophobic surfaces have recently attracted considerable attention in industry owing to their high water repellency and self-cleaning property. Many studies on the development of superhydrophobic surfaces have been reported, but the issues of the poor durability and difficulty in forming the desired hierarchical structures remain. Herein, a superhydrophobic surface with a hierarchical micro/nanostructure and good durability was developed on a poly(methyl methacrylate, PMMA) substrate. The micro-scale pillar array was first fabricated on PMMA by thermal imprinting. 1 H,1 H,2 H,2 H-perfluorooctyltriethoxysilane (PFOTES) was used to chemically modify silicon dioxide (SiO2) nanoparticles before developing nanostructure on the micro-scale pillar array. Subsequently, a nanocomposite suspension composed of polyvinylidene fluoride (PVDF) and PFOTES-SiO2 nanoparticles was sprayed on the pillar surface, forming the desired micro/nano hierarchical structure. The effect of the SiO2 nanoparticle size on the surface hydrophobicity was studied in detail. The good superhydrophobicity of the hierarchical surface, with a high contact angle of 163° and low sliding angle of 7°, was related to its high Brunauer-Emmett-Teller specific surface area of 42.43 m2 g−1 and pore volume of 0.35 cm3 g−1. The contaminants on the surface were cleaned easily as the water droplet rolled off, showing good self-cleaning performance. Owing to the binder of PVDF, the nanocomposite coating showed good adhesion to the PMMA substrate. The developed superhydrophobic surface is expected to be widely applied in self-cleaning, anti-fouling, and waterproof fields.