Facile construction of superhydrophobic polydopamine-based film and its impressive anti-corrosion performance on zinc surface

Abstract

Under weakly alkaline conditions, polydopamine (PDA) has strong adhesion to the surface of metal materials and chelate adsorption to nanoparticles. According to this characteristic, polydopamine (PDA) was formed by spontaneous polymerization of dopamine (DA), and then modified with octadecylamine (ODA) and 1H,1H,2H, 2H-perfluoro-decyl mercaptan (PFDT) to form a dense and uniform superhydrophobic film on the surface of zinc material. SEM, XPS, FTIR, SVET, electrochemical measurement (polarization curve and impedance spectroscopy) and other methods were used to characterize the surface morphology and chemical structures of samples before and after modification. The water contact angle (WCA) were further used to analyze the wettability of the superhydrophobic film. The experimental results show that the zinc surface with superhydrophobic PDA film exhibits higher corrosion resistance and lower corrosion current density than control groups, and the modification effect of PFDT is better. Moreover, the corrosion resistance of pure zinc can be significantly improved by the modification treatment, which is the effect of “micro nano structure air valley” formed by the superhydrophobic film layer and the enhancement of adhesion.