In Situ Self-Induced Synthesis of the Zinc Silicate/Polypyrrole Composite with Excellent Anticorrosion Performance

Functional corrosion inhibitors can enhance the anticorrosion performance of epoxy resin; however, traditional inhibitors tend to lose the structural integrity when the coating is damaged and fail to provide secondary protection to the metal substrate. In this work, the zinc silicate/polypyrrole (Zn₂SiO₄/PPy) composite was synthesized via an in situ self-induced polymerization method. During the salt water immersion test process, the artificially damaged coatings exhibited self-healing characteristics, attributed to the Fe³⁺ ions in the solution acting as an initiator for polypyrrole (PPy), causing the dissociated pyrrole monomer to continue polymerizing into PPy. In addition, the specific capacitance of Zn₂SiO₄/PPy composites increased by 11.67 F/g compared to Zn₂SiO₄, which indicates that Zn₂SiO₄/PPy has a higher specific capacitance for storing electrons. The contact angle of 74.0° for the Zn₂SiO₄/PPy composite coating was improved by 21.7 and 15.7° with Zn₂SiO₄ and PPy, reducing the contact area of water or other corrosive solutions on the coated surface. The impedance value of the Zn₂SiO₄/PPy composite coating was 16.62 times that of the epoxy resin at 120 h. This work provides a new approach to the development of self-healing corrosion inhibitors.