Synthesis and Characterization of Novel Fatty Alcohol Ethoxylate Surfactants for Corrosion Inhibition of Mild Steel

Novel fatty alcohol ethoxylate surfactants (NFAES) C1:(C12–C14–EO30) and C2:(C16–C18–EO30) were synthesized and characterized, and the effect of an increase of the hydrocarbon chain length at the same numbers of ethoxylated groups of these surfactants on the corrosion of mild steel (MS) in 1 M HCl was studied by different methods. These have revealed that the inhibition efficiency (IE%) increases with increasing the dose and the hydrocarbon chain length at the same number of ethoxylated groups in the surfactants (NFAES). The surfactants (NFAES) have a perfect performance as corrosion inhibitors. The results revealed that C2 > C1 in the IE% at the same studied dose of each surfactant, The IE% reached 85% at the very low dose of 30 ppm. Potentiodynamic measurements (PP) revealed that the NFAES surfactants are working as mixed type of inhibitors for both cathodic (reduction) and anodic (oxidation) reactions. The critical micelle dose for C1 is 350 ppm while for C2 it is 30 ppm. IE% acquired from PP, electrochemical impedance spectroscopy, and electrochemical frequency modulation are approximatly the same. The surface morphology was analyzed and is discussed.