Sandwich-like polyvinyl alcohol (PVA) grafted graphene: A solid-inhibitors container for long term self-healing coatings

Polyvinyl alcohol (PVA) grafted graphene was served as the container of solid inhibitors (cerium hydroxide). The graphene-PVA-Ce (rGPC) was embedded in polyvinyl butyral (PVB) coating and applied on mild steel. Artificial defects in the modified PVB coatings were produced. Electrochemical impedance spectroscopy (EIS) analysis was performed in 3.5 wt% NaCl solution at pH similar to 7 and pH similar to 4 respectively to study the corrosion-inhibition effect and long-term healing behavior of rGPC/PVB composite. From the results, the long-term healing properties of rGPC/PVB composite was confirmed. It is ascribed to the fact that the PVA-grafted graphene, with high encapsulating capacity and controllable release rate of inhibitors, provided a prolonged release of cerium inhibitor. The rGPC composite coating also has high impermeability and anti-corrosion performance. It is attributed to that rGPC has smaller size, better dispersion and stability than graphene-Ce when embedded in PVB coating.