The wide distribution of the lateral size of lab-prepared graphene oxide (GO) sheets often complicates the measurement of accurate average size. Herein, a series of reduced-GO/polyethyleneimine (RGO/PEI) composite membranes with compact brick-wall structures were successfully prepared. The large lateral size of RGO sheets in the membrane benefited gas barrier properties, including oxygen, nitrogen, and water vapor. The RGO sheets acted as impermeable inorganic filler to prolong the diffusion path, forcing gas molecules to wiggle through the permeable and tortuous channels of the PEI/water mixt...
