Covalently Integrated Graphene Oxide and Polyaniline via Dual Molecular Bridges for Highly Durable Waterborne Epoxy Anticorrosive Coatings

Waterborne epoxy (WEP) coatings are attractive for their low volatile organic compound emissions, but curing‐induced micropores limit long‐term corrosion protection. Herein, this work develops a dual‐modification and multi‐site molecular‐bridging strategy to construct covalently integrated graphene oxide/polyaniline (GO/PANI) hybrid fillers for WEP anticorrosive composite coatings. Using GO as the two‐dimensional framework, m‐phenylenediamine (MPD) and γ‐aminopropyltriethoxysilane (APTES) were sequentially introduced to generate amino‐containing anchoring sites, enabling multi‐site covalent grafting of PANI and suppressing GO restacking. The resulting A‐MPDGO@PANI exhibited improved dispersion and interfacial compatibility in WEP, contributing to a compact composite coating structure. The enhanced anticorrosion performance of A‐MPDGO@PANI/WEP was attributed to the synergistic effect of the A‐MPDGO two‐dimensional barrier and the electrochemical passivation behavior of covalently grafted PANI. Among the tested formulations, the coating with 20% aniline content showed the highest corrosion resistance, with a low‐frequency impedance modulus (| Z | f =0.01Hz ) of 3.20 × 10 9 Ω·cm 2 , approximately four orders of magnitude higher than that of pristine WEP. After 30 days of immersion in 3.5 wt% NaCl solution, the optimized coating maintained | Z | f =0.01Hz above 10 9 Ω·cm 2 and showed slight corrosion after 720 h salt spray exposure, demonstrating the potential of this molecular‐bridging strategy for durable waterborne epoxy composite coatings.