In this work, we report superior mass transport properties of polymers prepared by the covalent coupling of supermolecular carbon cages (e.g., fullerenes, bucky balls) to a poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) polymer. Dispersing the bucky balls into the polymer reduces gas permeability, whereas covalent bonding enhances permeability up to 80% in comparison to the pure PPO. Gas pair selectivity, however, is not compromised and stays constant.