Ionic liquids based gemini cationic surfactants as corrosion inhibitors for carbon steel in hydrochloric acid solution

Three ionic liquid based gemini cationic surfactants; N1,N1,N1,N2,N2,N2-hexadodecylethane-1,2-diaminium bromide (G2IL), N1,N1, N1,N2, N2,N2-hexadodecylpropane-1,3-diaminium bromide (G3IL) and N1,N1,N1,N2,N2,N2-hexadodecylhexane-1,6-diaminium bromide (G6IL) were synthesized and their chemical structures were elucidated by using FTIR and 1HNMR spectroscopic techniques. The physicochemical properties of ionic liquids were measured and discussed. The critical micelle concentration and surface properties were determined from their surface tension measurements. The performance evaluation of the synthesized inhibitors on the carbon steel corrosion in acidic environment (1.0 M HCl) have been investigated at different concentrations by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and weight loss techniques. Potentiodynamic polarization studies indicate that the studied inhibitors are mixed type inhibitors. For all inhibitors, the inhibition efficiency increases with increasing their concentration but decreases with increasing temperature. The adsorption of the ionic liquid surfactants on the metal surface and adsorption process obeys the Langmuir isotherm.