A novel intercalated MoS2 nanosheet with polyaniline to enhance anti-corrosion protection in epoxy coating

Abstract

The hindering feature of MoS2 nanosheets brings anticorrosion properties to polymeric coating, but its previous compatibility, derived from the inert pristine basal surface, heavily limits its homogenous desperation. However, after in-situ intercalation with PANI (g-PANI@MoS2), its compatibility with epoxy coating (EP) was greatly ameliorated. The conductive network formed by PANI with a conductivity of 3.52 × 10−5 S/cm in the coating could transfer the electrons generated by the corrosion reaction to prevent further corrosion. Meanwhile, the hydrophobicity of PANI and the two-dimensional structure of MoS2 provided the coating with excellent barrier properties. g-PANI@MoS2/EP maintained a high impedance value of above 1010 Ω cm2 even after being soaked in 3.5 wt% NaCl solution for 40 days, which was three orders of magnitude higher than EP. Furthermore, even if the coating was defective, PANI could form a passivation layer with an impedance value of 1.0 × 105 Ω cm2 at the defect, to maintain the protective ability of the coating. Therefore, the novel g-PANI@MoS2 not only presents significantly barrier and anticorrosion properties but also generates a self-healing passivation layer with additional corrosion resistance. The composite epoxy coating provides a long-term protection to metal substrates.