Sandwich-structured rGO/PVDF/PU multilayer coatings for anti-corrosion application

In this study, we fabricated a novel sandwich structure by combining reduced graphene oxide (rGO), polyvinylidene difluoride (PVDF) and polyurethanes (PU) to construct a composite film for anti-corrosion applications. The corrosion performances of the rGO/PVDF/PU multi-layered coatings on carbon steel were evaluated in 30 wt% boiling sulfuric acid solution for 1 h and 3.5 wt% NaCl electrolyte for electrochemical tests. The results show that the addition of PU and rGO dramatically improves the anti-corrosion performance of the bare PVDF coating and the optimized content of rGO is 7 wt%. The anticorrosion performances of corrosion potential, corrosion current and protection efficiency after protection coating are measured to be −757 mV, 0.1 μA cm−2 and 99%, respectively. The excellent results obtained could be explained by barrier effects, where the hydrophobic property and high-aspect-ratio of rGO in the PVDF matrix inhibit corrosion factors from diffusing into the substrate.