Anticorrosive property of heterocyclic based epoxy resins on carbon steel corrosion in acidic medium: Electrochemical, surface morphology, DFT and Monte Carlo simulation studies

Abstract Present study deals with the synthesis, characterization and inhibition property of two epoxy resins (ERs) namely,2,2′-(((sulfonylbis(4,1-phenylene)) bis (oxy))bis(methylene)) bis (oxirane) (ER1) and 2,2′-bis(oxiran-2-ylmethoxy)-1,1′-biphenyl (ER2) on carbon steel corrosion in 1 M HCl medium using experimental and computational methods. Results showed that inhibition efficiency of ERs increases on increasing their concentration. ER1 and ER2 showed highest inhibition efficiencies of 98.1% and 95.6%, respectively at 10 −3  M concentrations. Results showed that adsorption of ERs on the carbon steel surface obeyed the Langmuir adsorption isotherm. Scanning electron microscopy (SEM) study suggested that ERs protect the metallic superficial through their adsorption and development protective films. Different computational parameters such as ionization potential ( I ), electron affinity ( A ), energy band gap (Δ E ),electronegativity (χ ), dipole moment ( μ ), hardness ( η ), softness ( σ ), electrophilicity and ( ω ) nucleophilicity ( e ) were computed for neutral as well as protonated forms of ER1 and ER2. Adsorption behavior and the orientation of ER1 and ER2 on metallic surface were studied by Monte Carlo (MC) simulations. Results derived from different experimental methods were supported by computational studies using DFT and Monte Carlo methods.