Chitosan-Poly(aspartic acid) Microgel with Ionic Network for Dual Inhibition of Corrosion and Scale on Steel Surface

A bifunctional chitosan-poly(aspartic acid) (CS-PASP) microgel with ionic crosslinking network was fabricated via ionic coupling for simultaneous corrosion inhibition and calcium carbonate scale suppression on carbon steel. The fraction of PASP (fPASP) exhibits a dual regulatory effect on the interfacial adsorption of microgels, in which increasing fPASP monotonically enhances corrosion resistance in electrochemical tests, while moderate fPASP is identified as the optimal value to facilitate the formation of uniform adsorbed films on steel surfaces. Electrochemical and scale inhibition measurements confirm that the optimized CS-PASP microgel at 100 mg L−1 delivers outstanding dual performance, with high-scale inhibition efficiency maintained across a suitable concentration range and acceptable tolerance to moderate temperature fluctuation. The core innovations of this work lie in the constructed ionic crosslinking network structure, the dual-control mechanism combining electrochemical response and interfacial adsorption behavior, and the integrated excellent anti-scaling and anticorrosion capacities. This study provides a facile strategy for designing green multifunctional water treatment agents and deepens the fundamental understanding of PASP fraction-mediated interfacial protection behavior.