Structure and Sieving Mechanism of High Selective Graphene-based Membranes

Graphene oxide was used as charge able to confer high selectivity to the final product. A self-assembling technique, namely layer-by-layer has been developed to stratify graphene-based coating on polymeric films; this coating is composed by nanolayers of graphene oxide alternated with polymers, bonded each other by electrostatic forces. Permeability measurement on layered Matrimid, a commercial polyimide, showed incredibly high selectivity values to small particle mixtures, as O-2, CO2, He and H-2. Through simple post-treatments the selective performance was also improved, as demonstration of potentiality of the well-ordered hi-dimensional system: improvement on the coating would make this material one of the viable solution for industrial separations, e.g. hydrogen purification in sustainable energy production. A further investigation on similar structures obtained by other strategies shall demonstrate the peculiar mechanism occurring in this material for high selective performance.