Polymer–nanoparticle hybrid MnO2@PVA: Characterization and corrosion inhibition performance in acidic media

Polymer–nanoparticle hybrid materials offer adaptable platforms for corrosion inhibition in aggressive environments. In this study, manganese dioxide (MnO₂) nanoparticles were embedded into the polymer matrix of polyvinyl alcohol (PVA) to form a stable MnO₂@PVA nanocomposite film. Upon dissolution in 1 M HCl, the composite acted as a solution-phase corrosion inhibitor for carbon steel. Structural characterization confirmed uniform dispersion of spherical MnO₂ nanoparticles (55–100 nm) throughout the polymer. Electrochemical analysis revealed a marked reduction in corrosion rate (from 0.0211 to 0.0118 mm/year) and a significant increase in polarization resistance (from 1921 to 14,456 Ω·cm²), with inhibition efficiency reaching 43.8% (PDP) and 86.7% (EIS) at 300 ppm. Thermodynamic and adsorption studies indicated a spontaneous, chemisorption-driven interaction. The combined effect of MnO₂’s oxidative surface activity and PVA’s polymeric stability and solubility enabled sustained inhibition, demonstrating the potential of MnO₂@PVA as a tunable corrosion mitigation system for acidic environments.