Abstract: The inadequate dispersibility and weak interfacial bonding of hexagonal boron nitride (BN) nanosheets in polymer matrices hinder their application in high-performance marine protective coatings. Here, we report a supramolecular BN-P-CePN composite, synthesized via in situ polymerization of polydopamine (P) and self-assembly of cerium-tannic acid phenolic network (CePN), respectively, to address these challenges. This multifunctional nanofiller significantly enhances coating crosslinking density and filler-matrix interfacial interactions, achieving remarkable adhesion (5.7 MPa) and tensile stress (21.9 MPa) in the BN-P-CePN-EP coating. The intelligent supramolecular architecture enables dual-stimuli-responsive functionalities: photothermal confinement under 808 nm near-infrared irradiation and pH-triggered active corrosion protection. After 100 days of immersion in corrosive media, the BN-P-CePN-EP coating exhibits exceptional corrosion resistance (Z_f=0.01Hz=5.4 × 10⁹ Ω cm²), a 5934-fold improvement over pure EP coating. Additionally, synergistic UV absorption and radical scavenging by CePN supramolecules confer superior weather resistance to epoxy coating. This facile, scalable strategy not only advances BN-based composites for marine applications but also establishes a versatile platform for developing multifunctional coatings with integrated mechanical robustness, photothermal confinement, active protection, and long-term durability.

Key words: Supramolecular composite, Boron nitride, multifunctional coating, Photothermal confinement, Marine anticorrosion