Supramolecular Phytic Acid/Melamine Self‐Assembly Coatings for Flexible Polyurethane Foam With Superior Flame Retardancy and Fire‐Warning

A supramolecular phytic acid‐melamine biomass flame retardant, phytic acid‐melamine nanosheet (PAM), was synthesized and incorporated into a gelatin‐sodium alginate coating (GSPAM) for table. The 200 μm thick GSPAM coating adhered via hydrogen bonding and mechanical interlocking without compromising substrate flexibility. FPUF/GSPAM composites achieved exceptional flame retardancy: UL‐94 V‐0 rating, 37.0% LOI value, 69.6% reduction in peak heat release rate and 35.9% lower total heat release. Moreover, the coating enabled rapid fire warning within 2 s, with warning durations up to 190 s at high PAM content through proton‐hopping conduction. After 30 cyclic compression tests, the FPUF/GSPAM composites still maintains excellent resilience. The fire‐warning function was further integrated into an IoT‐based wireless alert system for real‐time monitoring. This work provides a multifunctional strategy harmonizing flame retardancy, mechanical reinforcement, and smart fire protection for FPUF.