Synergistic interfacial engineering of MnP@rGO heterostructures for mechanically robust, fire-safe, and thermally functional epoxy nanocomposite coatings

A green one-pot in-situ strategy constructs multifunctional MnP@rGO. • EP/4MnP@rGO achieves UL-94 V-0 rating with LOI of 29.5%. • PHRR and TSR are reduced by 40.2% and 49.7%, respectively. • Impact strength (+27.8%) and thermal conductivity (+284.2%) enhanced. • Excellent solar absorptance enables rapid photothermal de-icing. The intrinsic conflicts among mechanical robustness, fire resistance, and thermal functionality severely hinder epoxy resins (EP) in advanced applications. Conventional single-additive strategies inevitably compromise mechanical integrity and fail to address photothermal de-icing demands. Herein, we circumvent these limitations via a green one-pot in-situ reduction strategy that constructs a multifunctional manganese aminotrimethylene phosphonate@reduced graphene oxide (MnP@rGO) heterostructure without external reducing agents. This hybrid architecture exploits dual synergies, where the rGO scaffold ensures robust interfacial load transfer and physical barrier effects, while Mn 2+ centers serve as Lewis acid catalysts to promote cross-linking and graphitization of the degrading matrix into a protective char layer. At 4.0 wt% loading, the EP/MnP@rGO nanocomposite achieves a 27.8% enhancement in impact toughness and a 24.9% increase in tensile strength, alongside a UL-94 V-0 rating with 49.7% suppression in total smoke release and 46.4% reduction in total heat release. Moreover, the tailored interfacial structure imparts outstanding photothermal conversion efficiency, enabling rapid surface heating and reliable de-icing. This work establishes a transformative paradigm for converting an inherently compromised thermoset into an integrated multifunctional platform for protective coatings in icing-prone infrastructures such as wind turbine blades and aerospace composites.