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 ([C2(Bim)2]Cl2@CSM and [C6(Bim)2]Br2@CSM) are constructed as smart corrosion inhibitors to protect N80 steel in hydrochloric acid solution. The optimal inhibition efficiency of [C2(Bim)2]Cl2 and [C6(Bim)2]Br2 at 300 mg L-1 reaches 94.68% and 95.96%, respectively, indicating mixed-type inhibition behavior. On this basis, the prepared [C2(Bim)2]Cl2@CSM and [C6(Bim)2]Br2@CSM can proactively identify corrosive environments and protect the metal. The microspheres are pH-responsive owing to the presence of Schiff-base CN 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. Gemini imidazolium-based ionic liquids are newly synthesized as corrosion inhibitors to be loaded into chitosan microspheres (CSM) carriers. In 1 m HCl corrosive solution, such corrosion inhibitors are smartly released from CSM carriers to form a mixed adsorption layer on metal surface with dissociated CS chains. The smart response is sensitive and the corrosion inhibition performance is excellent.image (c) 2023 WILEY-VCH GmbH