Durable Superhydrophobic Nano-ZnO/Epoxy Composite Coating for Natural Gas Pipeline Corrosion Resistance

Natural gas pipelines face severe corrosion and hydrate deposition. Superhydrophobic coatings have potential but suffer from poor mechanical durability. Herein, a dopamine modification strategy is proposed, in which dopamine self-polymerizes on nano-ZnO to form a polydopamine (PDA) layer, improving epoxy compatibility and adhesion, thereby enhancing mechanical robustness and cohesion. A superhydrophobic coating (DZn) was fabricated by incorporating PDA-modified nano-ZnO into epoxy resin. DZn showed a water contact angle of 153.85° and a hysteresis of 3.11°. After 30 abrasion cycles, DZn retained its hydrophobicity, indicating excellent mechanical durability. DZn also achieved the highest adhesion grade (5B) and retained fouling-release capability under both acidic (pH = 1) and alkaline (pH = 13) conditions. EIS confirmed enhanced corrosion resistance, with an R c value of 9.18 × 10 9 Ω · cm 2 after 50 days of immersion, significantly higher than the control. This sustained R c indicates long-term stability of the trapped air layer, crucial for inhibiting hydrate nucleation and adhesion. This study demonstrates that dopamine modification effectively improves superhydrophobic coating performance, showing strong potential for internal pipeline protection against corrosion and hydrate deposition.