A lava-inspired micro/nano-structured ceramifiable organic-inorganic hybrid fire-extinguishing coating

Fire-retardant coatings have demonstrated effective fire protection for various materials, ranging from flammable polymeric foam and wood to nonflammable steel. However, the poor cost effectiveness has significantly impeded their real-world applications. In nature, lava is a flowing, noncombustible molten liquid with a low thermal conductivity. We, herein, report a lava-inspired micro/nano-structured ceramifiable organic-inorganic hybrid coating comprising low-melting glass powders (GPs), such as ceramic precursors; boron nitride (BN) nanosheets as synergists; and a fire-retardant polymer as a coating base. Upon exposure to flame, the coating forms a lava-like noncombustible ceramic char layer that can serve as a robust fire shield for underlying substrates. The hybrid coating-treated polyurethane foam exhibits a rapid self-extinguishing behavior and increased compressive strength, outperforming its previous counterparts. Meanwhile, the hybrid coating offers exceptional fire protection for solid wood and steel. This work provides a bioinspired strategy for creating cost-effective fire-retardant coatings for diverse industrial applications and a fire-safe world.