Development of an oxyresveratrol incorporated bio-based smart nanocomposite coating with anti-corrosive, self-healing, and anti-microbial properties

Abstract

Green and sustainable smart coatings with multiple functionalities that exhibit an excellent response to triggers, are essential in order to reduce energy consumption, usage of fossil resources, and to enhance economic impact. In the current work, oxyresveratrol (OXY) is extracted from coconut shell waste and subsequently used as a green corrosion inhibitor, encapsulated in mesoporous silica (MSNP) nanocontainers. Castor oil is a non-edible vegetable oil; it is epoxidized and crosslinked with bio-sourced citric acid and reinforced with oxyresveratrol-silica nanoparticles. The bio-based composite coating showed excellent anti-corrosive properties with improved thermal stability. At 2 wt% of OXY-MSNP content, the corrosion potential shifted to −0.028 V from −0.666 V, and the corrosion current reduced significantly from 30.53 μA cm⁻² to 0.0074 μA cm⁻² with an inhibition efficiency of 99.97%. The corrosive protection was found to be effective in 3.5 wt% NaCl solutions of acidic, neutral, and basic media, thus demonstrating the suitability of the coating in all environments. The coating also showed complete self-healing potential within 48 h, as confirmed by SEM micrographs, Electrochemical Impedance Spectroscopy and Potentiodynamic Polarisation studies. The coating inhibited the growth of both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria revealing a strong antibacterial effect. This type of bio-based self-sanitizing composite coating paves the way for the development of multifunctional smart coatings with self-healing, antimicrobial and anticorrosion properties from waste material in a sustainable manner.