Integrating PANI@BTA@MSN mesoporous nano-hybrid into zinc-rich epoxy coatings for long-term smart anti-corrosion durability

Zinc-rich epoxy coatings (ZRs) offer effective cathodic protection by combining metallic zinc fillers with organic barriers; however, issues with high zinc filler loading have prompted the exploration of alternative methods. This study investigates a novel approach, incorporating a Pani@BTA@MSN composite into ZR coatings to enhance long-term anti-corrosion durability. Here, a mesoporous silica nanoparticle (MSN) was synthesized as a mesoporous carrier for benzotriazole (BTA) and polyaniline (PANI), both of which contribute to the coating's corrosion resistance. The nano-hybrid structure was characterized using FTIR, FESEM, BET, UV–Vis, and TGA techniques. Electrochemical analyses, including EIS and Tafel tests, showed that inhibitor release from PANI@BTA@MSN increased |Z|_10mHz values to 2415 Ω·cm² after 24 h in saline solution, achieving an 82 % inhibition efficiency. Furthermore, EIS and OCP tests in the coating phase revealed that the intact composite-enhanced ZR coating extended cathodic protection from 10 to 20 days. After 65 days, the barrier performance improved by an order of magnitude compared to neat ZR coatings. FESEM/EDS mapping demonstrated the protective layer's formation, while pull-off adhesion tests showed minimal adhesion loss (5 %) in the PANI@BTA@MSN-ZR coating, underscoring its enhanced barrier and active anti-corrosion properties.