Multilayer coating for flame retardant foam or fabric

A method includes coating a substrate to provide a flame resistant substrate. In an embodiment, the method includes exposing the substrate to a cationic solution to produce a cationic layer deposited on the substrate. The cationic solution includes cationic materials. The cationic materials include polymers, nanoparticles, or any combinations thereof. The method further includes exposing the cationic layer to an anionic solution to produce an anionic layer deposited on the cationic layer to produce a bilayer. The bilayer is the anionic layer and the cationic layer. The anionic solution includes layerable materials.U