Mechanisms of friction and corrosion resistance in superhydrophobic waterborne polyurethane modified fluorinated polyurethane coatings

Fluorinated polyurethane coatings (FPU) are commonly employed for metal surface protection owing to its superior hydrophobicity. However, the coatings tend to be mechanically fragile, leading to a significant reduction in hydrophobic performance when exposed to external forces such as friction or abrasion. In contrast, waterborne polyurethane (WPU) exhibits excellent mechanical properties, including remarkable wear resistance and impact resistance. By integrating FPU with WPU, a superhydrophobic coating with enhanced mechanical stability and corrosion resistance has been successfully developed. Experimental results indicate that a high content of WPU compromises wear resistance, while a low content affects hydrophobic performance. Optimal performance is achieved when the WPU content is 10 %. The FPU&10%WPU coating not only demonstrates excellent superhydrophobic and self-cleaning capabilities but also retains its hydrophobic properties after experiencing wear. Additionally, electrochemical tests conducted over 7 days in a 3.5 wt% NaCl solution confirm the coating exceptional corrosion resistance.