Durable Superhydrophobic Bilayer Coating for Carbon Steel with Integrated Corrosion Resistance and Anti-icing Performance

To expand the application scope of carbon steel, imparting superhydrophobicity to its surface offers an effective strategy to overcome its inherently poor corrosion resistance. However, in marine environments, conventional superhydrophobic coatings often suffer from limited mechanical durability and inadequate long-term corrosion protection. In this study, a durable superhydrophobic bilayer coating composed of PDMS-MWCNTs (top layer) and PDMS (bottom layer) was developed to address these challenges. The top PDMS-MWCNTs layer imparted superhydrophobicity and effectively isolated the substrate from corrosive media, while the underlying PDMS layer enhanced adhesion and provided additional protection to the carbon steel. The resulting bilayer coating exhibited excellent self-cleaning properties, mechanical robustness, and chemical stability. Remarkably, the coating maintained stable superhydrophobicity in acidic, alkaline, and high- or low-temperature aqueous environments. Electrochemical measurements indicated a high inhibition efficiency (η) of 99.99%. Furthermore, the coating continued to exhibit strong protective performance after 30 days of exposure to a 3.5 wt % NaCl solution. In addition, the bilayer coating significantly delayed ice formation, with an icing time 7-8 times longer than observed for bare Q235, indicating excellent resistance to ice accumulation and effective ice removal capability. These results indicated that the fabricated superhydrophobic bilayer coating held significant potential for corrosion protection of carbon steel in diverse and harsh service environments.