A combined electrochemical and theoretical analysis of environmentally benign polymer for corrosion protection of N80 steel in sweet corrosive environment.

• Aniline based polymer as effective corrosion inhibitor for N80 steel. • Electrochemical measurements using potentiodynamic polarization and EIS. • SECM was used to study the localized electrochemical behavior. • SEM was used to observe the surface morphologies. • DFT and molecular simulations supported the experimental results. The corrosion inhibition efficiency of aniline, formaldehyde and piperazine based polymer (ADPD) on N80 steel in 3.5% NaCl solution saturated with carbon dioxide was investigated using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, weight loss, scanning electrochemical microscopy (SECM), scanning electron microscopy (SEM) measurements, density functional theory (DFT) and molecular dynamics simulation (MD). The adsorption of polymer onto N80 steel surface followed Langmuir adsorption isotherm model. Potentiodynamic polarization study confirmed that inhibitor is mixed type with cathodic predominance. SECM study reveals the current values decreases with the increasing concentration of polymer. SEM study supports the smooth metal surface texture. DFT and MD calculations are in agreement with the experimental findings. [ABSTRACT FROM AUTHOR]