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Superhydrophobic coatings often face challenges related to poor friction and corrosion resistance. In this study, composite coatings were developed, featuring a top layer of SiO 2 nanoparticles and a bottom layer of epoxy resin (EP) and polydimethylsiloxane (PDMS). As the number of SiO 2 nanoparticles layers increased, surface roughness escalated, and the coating structure transitioned from SiO 2 nanoparticles entirely encapsulated by EP and PDMS to a small fraction of SiO 2 exposed on the coating surface. Leveraging the rough surface and low-free-energy properties endowed by Si-(CH 3) 2 and Si-O-Si hydrophobic groups, coatings comprising 3–5 layers SiO 2 nanoparticles exhibited superhydrophobicity and self-cleaning capabilities. These coatings retained their superhydrophobic properties even after enduring heavy friction from sandpaper, and demonstrated robust corrosion resistance over extended periods. Increasing the number of SiO 2 layers not only enhanced superhydrophobicity, corrosion and friction resistance, but also improved the coating-substrate adhesion. The designed coating structure exhibited superior corrosion resistance and coating-substrate adhesion compared to those of EP/PDMS + SiO 2 double-layer and EP + PDMS + SiO 2 mixed coatings. Moreover, the coatings displayed a self-healing ability, regaining superhydrophobicity following O 2 or Ar etching, facilitated by the upward movement of hydrophobic groups/bonds and intensity recovery. Coatings subjected to Ar etching exhibited better self-healing properties due to higher Si-O-Si and lower C-C/C-H bond intensities. This research presents novel insights for the practical application of superhydrophobic coatings. • Coating structure with all or a part of SiO 2 surrounded by EP and PDMS was designed. • Rough surface with low surface energy led to coating superhydrophobic and self-clean. • Improving SiO 2 layers number achieved good adhesion, corrosion and friction durability. • Coatings present better corrosion durability and adhesion than other structure design. • Hydrophobic groups floating up and intensity recovery were coating self-heal reason. [ABSTRACT FROM AUTHOR]

The lack of durability in superhydrophobic coatings has restricted the practical applications of coatings in the fields of marine and construction. In this paper, the composite coatings of epoxy resin (EP), polydimethylsiloxane (PDMS) and SiO 2 nanoparticles were prepared by using the room-temperature liquid spraying and laser curing methods. The effects of the laser curing powers on the microstructure, hydrophobicity, durability in terms of corrosion and friction of the coatings were researched. The results demonstrate that there were micropores and aggregated SiO 2 nanoparticles on the surface of coatings. The coatings had the growth structure with SiO 2 nanoparticles partially embedded into the PDMS and EP bottom layer, and PDMS in the bottom layer migrating upward. With the increase of laser curing powers, the nanoparticles gathered significantly and the micropores was decreased. Under different laser curing powers, the coatings had the Si-(CH 3) 2 hydrophobic group and exhibited superhydrophobicity. All the coatings showed excellent self-cleaning performance in muddy water and ink. As the laser curing power increased, the superhydrophobicity of the coating was increased (the maximum contact angle of the coating was up to 161.90 ± 1.85°). Moreover, the coatings had strong corrosion resistance after being immersed in artificial seawater for 72 h. The coatings still had the superhydrophobicity after 100 cycles of load friction. With the increase of laser curing power, the friction resistance of the coating was improved, and the corrosion resistance was first improved and then reduced. This study provides a new idea for obtaining superhydrophobic and strong durable coatings. [Display omitted] • Laser curing was effective applied to improve durability of EP + PDMS/SiO 2 coatings. • All the coatings exhibit superhydrophobic and self-cleaning performances in sewage. • Coatings still exhibit superhydrophobicity after 100 cycles of 200 g load friction. • Superhydrophobicity and friction resistance improve by increasing laser curing power. • Coatings are strong corrosion resistance against artificial seawater exceed 72 h. [ABSTRACT FROM AUTHOR]