**4.5 Wettability**

The capability of a liquid to comes in contact with a surface of a solid and maintains it; this process is known as wettability. The adhesive and cohesive interaction helps in maintaining the interaction between liquid to solid and liquid to liquid. This property of gemini imidazoline surfactant increases with a decrease in the

hydrophobic group length in the chain present in the surfactant. Whereas, the fall in the concentration of gemini imidazoline surfactant resulted in a decreased in the rewet ability and vice-versa [1, 20].

### **4.6 Inhibitor**

Surfactants are used as corrosion inhibitors; they act as a protector on metal surfaces from corrosion. The gemini surfactants are amphiphilic, hence develops an affinity at metal/metal oxide–water interfaces for adsorption phenomena which leads to creating a barrier on metals and metal oxides surfaces and inhibits corrosion [36]. Imidazoline plays a vital role in corrosion inhibition as the imidazoline ring bond with the planar alignment to the surface of the metal. Further studies showed that the imidazoline inhibits the corrosion by blocking, activating, and using energy-related aspects together [37, 38].
