Development of superhydrophobic layered double hydroxide directly on zinc substrate: structural and corrosion resistance properties

Abstract

This study is aimed to study the functionalization of zinc metal surface with the development of layered double hydroxides (LDHs) and was modified further to develop superhydrophobic LDHs thin film. The influence of the protective LDHs on physical–electrochemical properties and the chemical state of the surface against different reagents (NaOH, NaCl, acidic solution) for self-cleaning characteristics are reported. The structural characteristics of developed coatings were evaluated by scanning electron microscopy (SEM-EDS) and X-ray diffraction (XRD), while electrochemical impedance spectroscopy (EIS) measurements were performed in NaCl solution to analyse the importance of protective coating. The research demonstrates that active and passive corrosion protection by the LDH conversion film against electrolytic species yields a substantial enhancement in corrosion resistance properties. The superhydrophobic surface, by incorporating CF3(CF2)9CH2CH2Si(O-)3 groups (PDFTS) in ZnAl–LDHs, has shown significant corrosion protection efficiency after 7 days of immersion in 0.1 M NaCl solution with an increase of almost three orders of magnitude in the |Z|10 mHz in comparison to untreated zinc surface, which can lead to important values for more potential applications.