*5.2.1 Corrosion inhibitor*

Zhuang et al. examined the corrosion inhibition property of gemini imidazoline surfactant on copper. They synthesized the imidazoline gemini surfactant using saturated fatty acids and studied the property by electrochemical method. Copper was taken in NaCl solution and according to the work, it showed that various factors like pH, surfactant concentrations, and length of carbon change affects the suppressive efficiency. The inhibition effect was better with the increase in gemini imidazoline surfactant concentration whereas suppressive efficiency is more when the length of the carbon chain is short [13].

Yang et al. synthesized the gemini imidazoline surfactant by adding oleic acid with triethylenetetramine (2:1). They studied the inhibition of carbon dioxide corrosion by linear polarization resistance in sparged beaker testing and concluded that the less concentration of gemini imidazoline was effective as corrosion inhibition when compared with traditional imidazoline and emulsion tendency was less than traditional imidazoline. The synthesized gemini imidazoline with oleic acid has improved film persistency, Higher surface activity, lower critical micelle concentration than traditional imidazoline. Therefore, this is a better surfactant as it is polluting the environment less than conventional imidazoline and also have better corrosion inhibition property [44]. Obot et al. also studied the corrosion inhibitors and concluded that the imidazoline based gemini surfactants are good corrosion inhibitors [37].
