Polyethyleneimine-assisted supramolecular self-assembly of cerium-phenol-amine system on boron nitride surfaces for anticorrosive coatings with active pH responsive behavior and enhanced barrier performance

In this study, cerium-phenol-amine modified boron nitride nanosheets were successfully synthesized via a facile polyethyleneimine-mediated mechanical exfoliation and in-situ supramolecular self-assembly strategy. This approach was designed to endow boron nitride nanosheets (BNNS) with enhanced physical barrier properties and pH-responsive active anticorrosion functionality. When incorporated into a waterborne epoxy (WEP) coating, the resulting CTP-BNNS composite exhibited exceptional long-term shielding performance and significant self-healing capabilities in damaged areas. UV–vis spectroscopy confirmed the acid-triggered release of cerium ions, highlighting the stimulus-responsive nature of the assembly. Electrochemical impedance spectroscopy (EIS) revealed that the low-frequency impedance modulus (|Z|0.01 Hz) of the CTP-BNNS/WEP coating maintained a remarkable value of 4.00 × 109 Ω·cm2 after 75 days of immersion in 3.5 wt% NaCl solution, which was much higher than that of pure WEP coating (6.50 × 107 Ω·cm2). Furthermore, molecular dynamics simulations indicated that the CTP-BNNS/WEP system possesses superior impermeability, characterized by significantly reduced fractional free volume and lower diffusion coefficients for O2, H2O and Cl−. The synergy between the inherent impermeability of 2D BNNS and the cerium-phenol-amine active system not only strengthens the interfacial adhesion between the filler and the resin matrix but also imparts a dual-functional “passive-active” protection mechanism. This work provides a robust strategy for engineering high-performance, long-term anticorrosive coatings through the functionalization of exfoliated 2D nanomaterials.