Wrinkled p-phenylenediamine grafted graphene oxide as reinforcement for polyvinyl butyral anti-corrosive coating

Wrinkled p-phenylenediamine (PPD)-functionalized graphene oxide (PGO) is synthesized, characterized, and subsequently incorporated in a ethanol-based polyvinyl butyral (PVB) film (ca. 10 mu m thick). The anti-corrosive properties of the pure PVB and nanocomposite (PVB-PGO and PVB-GO) films are tested on steel and compared. Electrochemical impedance spectra reveal that the PGO-reinforced PVB nanocomposite film exhibits the slowest corrosion rate (4 x 10(-4) mm a(-1) after a 20-day immersion) among the samples, and the results of 7-day saline spray bombardment tests show it is the most robust and durable. The PVB-PGO coating protects the steel substrate from visible corrosion. Incorporation of GO in the PVB matrix results in a reduction of the PVB film anti-corrosion properties. However, by functionalizing GO with PPD, highly dispersible wrinkled PGO flakes are obtained, thus leading to a uniform film that presents a highly tortuous path for impeding liquid and gas molecules. The PVB-PGO nanocomposite film exhibits high, stable capacitance without film delamination, cracking, or other visible damage. Readily accessible as a simple and environmentally friendly, this approach may present an advantageous strategy for creating protective coatings in marine and other applications.