Poly(vinyl alcohol) for multi-functionalized corrosion protection of metals: A review

The abuse of toxic substances and organic solvents in metal corrosion protection seriously threatens human health, environment, and ecosystem. It is an inevitable tendency to replace the harmful materials with biodegradable materials in future anti-corrosion technologies. Poly(vinyl alcohol) (PVA) is a polyhydroxy water-soluble biodegradable polymer with excellent film-forming property, adhesive property, emulsifiability, spinnability and biocompatibility, which can be used as a good candidate material towards greening of metal corrosion protection. In this review, the multifunctional applications of PVA in the fields of metal corrosion protection were systematically summarized, including corrosion inhibitor, chemical conversion coating, anticorrosion coating, nanofiller, microcapsule, and nanofiber mat. To conclude, PVA has been successfully used to fabricate individual inhibitors and composite inhibitors for different types of metals. The special molecular structure of PVA endows it with unique interfacial compatibility in chemical conversion coating, anti-corrosion coating, and nanofiller to improve the protective properties against corrosion. As an environment-friendly emulsifier, PVA has a promising application potential in promoting the greener production of anti-corrosion microcapsules. However, due to water-solubility of PVA, its practical application in the water environment is limited, which directs a great opportunity for future research. In the field of electrospinning, PVA fibers can also be used as carriers for various additives such as self-healing and self-reporting agents, which brings new prospects for the development of smart anti-corrosion coatings. With the increasingly stringent environmental protection policies, PVA can play a more important role in low-toxic, even non-toxic metal corrosion protection technologies, and help the development of green chemistry concept in corrosion field.