Graphene oxide nanobrick wall for gas barrier and fire protection of polystyrene

Graphene’s highly conjugated network makes processing difficult, limiting its functionality. Graphene oxide (GO) is a popular graphene derivative that allows for water-based processing, while retaining many of graphene’s desirable barrier properties. Polyethylenimine (PEI) and GO were alternately deposited via layer-by-layer assembly, thickened with tris(hydroxymethyl) aminomethane (tris), onto polystyrene, and subsequently reduced (rGO) to evaluate the gas barrier and fire protection of the resultant coating. An eight bilayer PEI + tris/rGO coating has an oxygen transmission rate of 2.88 cm³ m⁻² day⁻¹ atm⁻¹, which is a 400 × reduction compared to uncoated polystyrene. This 5 μm coating also imparts self-extinguishing behavior following direct flame exposure. This multifunctional film is the first highly aligned graphene oxide nanoplatelet coating to incorporate an amine salt to yield micron-thick films that are suitable for both gas barrier and heat shielding applications.