Cobaltocenium-Based Metallosurfactants with Unconventional Acid-Resistant Corrosion Protection Behavior

Developing highly efficient surfactant-based corrosion inhibitor with multiple interaction sites toward metal surface is crucial for both industry and academy, which can advance the understanding of the anti-corrosion mechanism and the structure-activity relationship of inhibitor. However, achieving this goal remains a challenge because of the limited variety of ionic group and the structure of surfactant. Herein, a series of cobaltocenium-based metallosurfactants is developed through click chemistry, where the cationic cobaltocenium is an ionic group and triazole is a potential coordination site with a metal surface. These metallosurfactants exhibit lower critic micelle concentration than corresponding quaternized ammonium with the same alkyl chains. Owing to the synergetic effect from coordination between triazole and metal surface as well as potential electrostatic interactions between cobaltocenium/protonated triazole with metal surface, these metallosurfactants exhibit highly efficient anti-corrosion performance to mild steel with inhibitive efficiency as high as 95%. Moreover, such a synergetic effect enforces the hydrophilic group anchored to the metal surface and the tilted angle of the hydrophobic chain increases by increasing the chain length, which results unconventional acid-resistant corrosion protection behavior.