Water soluble redox‐active polyurethanes as efficient corrosive inhibitors for mild steel

Abstract There is a necessity for an eco‐friendly inhibitor technology to safeguard mild steel from corrosion. Redox‐active Oligoanilines, namely diamine‐capped trimer (DCTA) and tetramer (DCTAni) have been synthesized and incorporated into the polyurethane backbone derived from polyethylene glycols (PEG, Mw = 2050, 4000) and toluene diisocyanate (TDI). The four water‐soluble polyurethanes, resulting from PEG, TDI, and DCTA/DCTAni, were denoted as IH‐1, IH‐2, IH‐3, and IH‐4. The corresponding redox‐active polyurethanes were rationally characterized using FTIR, and UV–visible spectroscopies. Scanning electron microscopy (SEM) was employed to investigate the surface morphology. The electrochemical properties of these inhibitors were characterized by cyclic voltammetry (CV). All the inhibitors were studied for their corrosion inhibition efficiency using Tafel potentiodynamic polarization analysis and weight loss methods. These demonstrated high efficacy at a low concentration of 200–300 ppm. The absorptivity of polymers on the mild steel were confirmed by Langmuir adsorption isotherms with a well‐fitting ( R 2 = 99.9%). The SEM analysis showed the adsorption capacity of inhibitors as protective layers for the mild steel panels. Overall, this work paves the way for innovative ideas for producing more water‐soluble and electrochemically active polymer additives as excellent corrosive inhibitors for mild steel surfaces.