Non-covalent and covalent-synergistical-interaction assembled GO self-supporting membrane with excellent alignment for ultrahigh H2 barrier applications

The emerging graphene oxide membranes (GOm) showcase superiority in molecule barrier applications, yet their hydrogen (H 2 ) barrier performance is still less than ideal due to the insufficient control of GOm assembly architecture. Here, molecular patch engineering, in which amino rich polyethyleneimine (PEI) is controllably introduced into the GO system, is proposed to construct a highly aligned self-supporting PGO membrane (PGOm) for exceptional H 2 barrier performance. Based on the non-covalent and covalent interactions between GO nanosheets and PEI, the assembly behavior of GO nanosheets from the liquid phase to the solid phase is efficiently optimized in both extension and alignment synergistically, resulting in the superior alignments of PGOm with a Herman's orientation factor as high as 0.86. Owing to the excellent alignments, the hydrogen permeability (P H2 ) of PGOm is substantially reduced to a mere 2.28 cm 3  cm/(cm 2 ·s·Pa)·10 −15 even at a high temperature of 80 °C, representing a remarkable three-order-of-magnitude decrease compared to GOm. Additionally, at 25 °C, the P H2 of PGOm-enhanced epoxy sandwich composites is minimized to 1.2 cm 3  cm/(cm 2 ·s·Pa)·10 −15 , approximately 50 times lower than that of pure EP. This highlights the significant potential of PGOm in enhancing the gas tightness of composite pressure vessels.