Core/shell (ZnO/polyacrylamide) nanocomposite: In-situ emulsion polymerization, corrosion inhibition, anti-microbial and anti-biofilm characteristics

Polyacrylamide nanoparticles of 20 nm were prepared using emulsion polymerization technique. Core/shell nanocomposites of functional core of zinc oxide nanoparticles surrounded by a shell of polyacrylamide were also prepared using in-situ emulsion polymerization technique. Potentiodynamic polarization and Electrochemical impedance parameters for corrosion of carbon steel in absence and presence of ZnO/PAM.NCs indicated that, as the ZnO nanoparticles ratio increased, the corrosion inhibition efficiency increased; 50%, 80% and 94% for 1, 5 and 10% ZnO; respectively. Scanning electron micrographs of carbon steel specimen surface immersed in HCl in absence and presence of ZnO/PAM.NC10 indicated that carbon steel surface is less damaged in presence of ZnO/PAM.NC10 which confirms the observed high inhibition efficiency. ZnO/PAM.NC10 was found to display a broad spectrum antimicrobial activity with the inhibition zones in the range of 15-22 mm. ZnO/PAM.NC10 demonstrated a higher antibacterial activity for the Gram-positive than for the Gram-negative bacteria and exhibited lower minimum inhibitory concentrations and minimum bactericidal concentrations for the Gram negative bacteria than the Gram positive bacteria. Moreover, it showed MICs/MFCs against yeast and fungal strains at concentrations (250/250 ppm). Additionally, ZnO/PAM.NC10 exhibited antibiofilms activity against the standard bacterial strains; Bacillus subtilis and Escherichia coli as confirmed by SEM imaging. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.