Superhydrophobic, Highly Adhesive, and Corrosion-Protective Fluoropolymer-Modified Polythiophene Coatings

In this study, we introduce an approach aimed at enhancing the adhesion, surface stability, water repellency, and corrosion resistance of electrodeposited polythiophene (PTH) coatings by integrating a thienyl-substituted silane coupling agent as a surface modifier alongside poly(vinylidene fluoride-co-hexafluoropropylene) as a topcoat. The fluoropolymer inclusion further improves the resultant coating's water repellency, while the utility of a silane coupling agent addresses a crucial, yet often overlooked, issue in polymeric coatings─ensuring strong adhesion to steel substrates. Spectroscopic analyses confirm the silanization of steel, indicating a strong chemical bond between the substrate and coating. Subsequent tape adhesion tests substantiate this finding, revealing minimal coating delamination and corroborating the enhanced adhesion achieved. Even after rigorous cyclic corrosion tests, the coating maintains a consistently high water contact angle (∼163°), demonstrating remarkable stability and durability, while impedance measurements and potentiodynamic polarization unveil a notable increased corrosion resistance (low-frequency impedance modulus, |Z|0.1 Hz ∼ 7.2 MΩ cm2, corrosion potential, ECORR ∼ 0.14 V, and corrosion current, ICORR ∼ 0.76 nA). Our approach, unprecedented in existing literature, not only extends the lifespan of PTH coatings but also broadens their utility in corrosion-prone environments. Overall, this study sets a new benchmark for developing durable and hydrophobic protective coatings, offering a promising avenue for future research and industrial applications.