Improvement of superhydrophobicity and durability of EP+PDMS/SiO2 composite coatings by adjusting laser curing powers

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 SiO2 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 SiO2 nanoparticles on the surface of coatings. The coatings had the growth structure with SiO2 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-(CH3)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 degrees). 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.