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 anticorrosion 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 mu A cm(-2) and 99%, respectively. The excellent results obtained could be explained by barrier effects, where the hydrophobic property and high-aspectratio of rGO in the PVDF matrix inhibit corrosion factors from diffusing into the substrate.