Enhancing adhesion and durability: A biomimetic approach with dopamine-modified lignin-polydimethylsiloxane coatings

Corrosion causes significant challenges in industrial settings, leading to economic losses and safety concerns. Previously, we developed a lignin-polydimethylsiloxane (lignin-PDMS) coating that exhibited high corrosion resistance. However, the adhesion of the developed lignin-PDMS coating to carbon steel was limited, affecting its overall performance. To address this, we incorporated dopamine (DOPA), known for its strong adhesive properties, as a pre-treatment before applying the coating. It was found that the adhesion and corrosion resistance of lignin-PDMS coated steel could be improved by adjusting the pH value of the DOPA solution. The steel treated with pH 4.5 DOPA solution showed two times higher adhesion strength to the coating than non-treated steel. After the DOPA treatment, the coating can maintain high barrier property for at least 3 months in 1 M NaCl solution, which is even better than commercial gelcoat, demonstrating super corrosion protection. Quartz Crystal Microbalance with Dissipation (QCM-D) and X-ray Photoelectron Spectroscopy (XPS) analyses confirmed the DOPA deposition on the steel surface. Our findings show that the DOPA-lignin-PDMS system is an environmentally friendly and efficient solution for enhancing the durability of steels in corrosive environments. •Dopamine improves lignin-polydimethylsiloxane coating’s adhesion on steel.•pH 4.5 dopamine solution doubles coating’s adhesion strength on steel.•Coating on dopamine-treated steel maintains barrier property for 3 months in 1 M NaCl.•Dopamine-lignin-polydimethylsiloxane system enhances the durability of steels in corrosive environments.