Water-resistant and flame-retardant waterborne polyurethane coating based on hydrophobic SiO₂ and microcapsule perfluorohexanone: With automated intelligent fire early warning and fire protection

This is the first report of a Waterborne Polyurethane Coating integrating microcapsule perfluorohexanone (1230) for autonomous fire suppression. The coating features a unique thermochromic system that exhibits visible color transition at 80 °C, providing real-time thermal hazard alerts, while 1230 automatically ruptures at 125 °C to release flame-suppressing agents. Hydrophobic SiO₂ nanoparticles (10 wt%) enhance surface roughness (a 32.1 % increase inwater contact angle) and catalyze condensed-phase char formation, synergizing with the gas-phase radical scavenging from 1230 to achieve a 15.7 % reduction in peak heat release rate. Comprehensive characterization, including TG, SEM, FT-IR, XPS, and XRD confirms uniform filler dispersion and chemical stability, accelerated aging tests demonstrate sustained performance under 85 % RH/55 °C and salt spray conditions, while TG-IR analysis reveals suppressed pyrolysis products, underscoring the coating's eco-friendly profile. This work provides a scalable strategy for designing multifunctional coatings, ridging gaps in fire safety, environmental durability, and intelligent fire early warning.