Mussel-inspired polydopamine and Al2O3 nanoparticles co-modified MoS2 for reinforcing anticorrosion of epoxy coatings

A novel Al 2 O 3 –PDA–MoS 2 nanohybrid was synthesized by depositing Al 2 O 3 nanoparticles on the surface of molybdenum disulfide (MoS 2 ) sheets covered with polydopamine (PDA). Many characterizations demonstrated that the Al 2 O 3 was successfully deposited on the surface of MoS 2 . It was found that when the mass ratio of PDA–MoS 2 to Al 2 O 3 was 1.5:1, the nano-hybrid filler showed good dispersion performance. Then, the composite coating samples were prepared by adding Al 2 O 3 –PDA–MoS 2 (1.5:1) hybrid to waterborne epoxy resin. The effects of Al 2 O 3 , MoS 2 , and PDA–MoS 2 on the corrosion resistance of epoxy coating were also investigated. The potentiodynamic polarization test demonstrated that Al 2 O 3 –PDA–MoS 2 nanohybrids had excellent corrosion inhibition properties. The results of electrochemical impedance spectroscopy also revealed that the impedance modulus of Al 2 O 3 –PDA–MoS 2 /EP composite coating was nearly two orders of magnitude higher than that of pure epoxy resin after immersion in saline for 21 days. This study confirmed that Al 2 O 3 –PDA–MoS 2 nanosheets had better barrier properties and corrosion inhibition properties, and provided a new idea for the wide application of nanofillers in the field of anticorrosion.