Surface-active antimicrobial and anticorrosive Oleo-Polyurethane/graphene oxide nanocomposite coatings: Synergistic effects of in-situ polymerization and π-π interaction

Abstract Inhibition of electrochemical and microbial corrosions is one of the prominent importance in both industrial and environmental applications. Therefore, we have designed a sustainable surface-active bi-functional (antimicrobial/anticorrosive) polyurethane nanocomposite (PUC) coating by means of synergistic effects of π-π interaction and in situ incorporation of graphene oxide (GO) for the first time. The PUC was synthesized using Pongamia oil, acrylic acid (to induce π-π interaction), GO (biocidal and reinforcing agent), and toluene diisocyanate (TDI) via one-pot addition polymerization. These interactions improved GO distribution, which influenced the structure and segmental dispersion within the PUC network. Further, it was observed that the properties (physical, mechanical, thermal, barrier, and adhesion) of the synthesized PUC coating were significantly improved. The electrochemical studies confirmed that upon addition of small amount of GO (0.5 wt.%) the anticorrosive behavior of PU nanocomposite coating was increased, exhibiting high corrosion potential (Ecorr= -0.179 V), low corrosion current density (Icorr = 2.3 × 10−11 A. cm-2), and enhanced impedance modulus at low frequency (|Z|0.01 Hz = 3.6 × 1010 Ω cm2) even after 21 days of immersion (5% NaCl solution). Besides, the surface activity of the PUC coating was confirmed by its strong contact-killing effect against Gram-positive and Gram-negative bacteria. Based on these results, present work provides a facile route towards the development of high-performance dual-functional coatings that may find a wider scope of applications in various industries like maritime, food, fuel and healthcare.