pH-Responsive Chitosan Microspheres Loaded with Gemini Imidazolium-Based Ionic Liquids as Smart Corrosion Inhibitors for N80 Steel in Hydrochloric Acid Solution

Chitosan microspheres (CSM) loaded with synthesized Gemini imidazolium-based ionic liquids ([C 2 (Bim) 2 ]Cl 2 @CSM and [C 6 (Bim) 2 ]Br 2 @CSM) are constructed as smart corrosion inhibitors to protect N80 steel in hydrochloric acid solution. The optimal inhibition efficiency of [C 2 (Bim) 2 ]Cl 2 and [C 6 (Bim) 2 ]Br 2 at 300 mg L −1 reaches 94.68% and 95.96%, respectively, indicating mixed-type inhibition behavior. On this basis, the prepared [C 2 (Bim) 2 ]Cl 2 @CSM and [C 6 (Bim) 2 ]Br 2 @CSM can proactively identify corrosive environments and protect the metal. The microspheres are pH-responsive owing to the presence of Schiff-base C═N bonds and the loaded inhibitors can be released rapidly in acidic environment. Released inhibitors are delivered to corroded sites and synergistically interact with decomposed microspheres for enhanced corrosion inhibition effect.