Poly(vinylidene fluoride)/molybdenum disulfide nanocomposite coatings: Studying the surface properties and corrosion protection

Abstract Robust nanocomposite coatings based on polyvinylidene fluoride (PVDF) and molybdenum disulfide (MoS₂) nanoplatelets were prepared by a spray coating method. To achieve various surface structures, the coatings were dried at room and oven temperatures (20 and 200°C). All the samples dried at room temperature exhibited a highly porous surface structure, attributed to the strong nonsolvent role of water vapor, which triggered the nonsolvent‐induced phase separation (VIPS). On the other hand, the oven‐dried coatings showed a dense structure with no pores, resulting from eliminating the VIPS process by enhancing the drying temperature. MoS₂ nanoplatelets were localized at the surface layer and the adjacent beneath layers. The formation of α‐type PVDF crystals was intensified for the oven‐dried samples based on the surface morphology and X‐ray diffraction patterns. Roughness analysis demonstrated that MoS₂ nanoplatelets interfere with the phase separation process leading to a lower porosity for the room‐dried coatings. The elimination of porosity by increasing the drying temperature caused the hydrophobicity of the coatings to be notably decreased. Polarization and electrochemical impedance spectroscopy results revealed that both polymeric and nanocomposite coatings improved the corrosion resistance of the aluminum substrates, and the oven‐dried pure PVDF coating exhibited the highest level of corrosion protection.