Fabrication and Characterization of Superhydrophobic Poly(vinylidene fluoride-co- hexafluoropropylene)/TiO2 Nanocomposite Coating for Corrosion Protection Applications

Superhydrophobic surfaces have a strong potential for implementation in variety of fields, including self-cleaning surfaces, biomedical and coatings for corrosion protection. Preparation of superhydrophobic surfaces requires both an optimum roughness and low surface energy; therefore, these surfaces are conventionally prepared employing two steps: roughening a surface and lowering its surface energy.  

In this study, the superhydrophobic Poly(vinylidene fluoride-co-hexafluoropropylene)/TiO₂ nanocomposite coatings were fabricated  using a simple one-step coating method on a carbon steel substrate to study the corrosion behavior in harsh environments. The surface wettability and morphology of the prepared coatings were characterized using  the sessile droplet method and scanning electron microscopy, respectively. X-ray photoelectron spectroscopy and X-ray diffractometer were used to identify the elemental composition and chemical oxidation states of the prepared surface. The surface roughness of the coatings was measured using atomic force microscope. The chemical stability of the prepared coatings was inspected by immersion the specimens in different pH solutions. The results showed that stable superhydrophobic surfaces with high water contact angle and low contact angle hysteresis can be fabricated on the carbon steel surface. As well as, the corrosion resistant performance of the produced superhydrophobic surface on carbon steel was carried out by electrochemical impedance spectroscopy (EIS) measurements and potentiodynamic polarization in 3.5 wt % NaCl solution.  The electrochemical corrosion tests revealed that the as-prepared superhydrophobic surface significantly improved the corrosion resistant of the C-steel substrate.