A bird nest-inspired and fully biomass coating with an interpenetrating fibrous network for thermal insulation and universal fire retardancy

. The synergy of decarboxylation/carbonization and radical scavenging imparts self-intumescent barrier properties and universal flame retardancy to diverse materials (fabric, RPUF, paper, wood), yielding a limiting oxygen index of 25-30%, and smoke and toxic gas suppression. This work presents a biomimetic strategy for sustainable, high-performance flame-retardant coatings with broad applicability.