Preparation and characterization of pH-controlled-release intelligent corrosion inhibitor

•A pH-controlled-release intelligent corrosion inhibitor was designed, which performed long-term inhibition capability in the solution.•The pH-sensitive hydrogel was prepared via grafting the mixtures of acrylic acid (AA) and 2-hydroxy ethyl methacrylate (HEMA) onto potato starch backbones.•The hydrogel exhibited a high swelling degree in alkaline solutions and excellent sensitivity to the pH of the medium.•The intelligent corrosion inhibitor showed a favorable drug release property and could effectively sustain in a long cycling life.

A pH-controlled-release intelligent corrosion inhibitor is designed, which performs long-term inhibition capability in the solution. The pH-sensitive hydrogel was prepared via grafting the mixtures of acrylic acid (AA) and 2-hydroxy ethyl methacrylate (HEMA) onto potato starch backbones. Increasing pH generally produced an increased swelling of the hydrogel which peaked at pH 8.0. The hydrogel also showed a fast and reversible swelling behavior when alternately immersed in pH 1.0 and 8.0 solutions. A corrosion inhibitor, 1 H-Benzotriazole (BTA), was loaded into the hydrogels and the cumulative release capabilities were studied at different pH. From the electrochemical measurement and scanning electron microscopy (SEM) analysis, the intelligent corrosion inhibitor exhibited an improved long-term inhibition ability on aluminum alloy due to the controlled-release behaviors.