Effect of high molecular weight polyethyleneimine functionalized graphene oxide coated polyethylene terephthalate film on the hydrogen gas barrier properties

Fabrication of high-performance graphene-based polymeric composites is challenging due to poor dispersion of graphene caused by restacking, weak interfacial bonding, and incompatibility of graphene with polymers. Herein, reduced graphene oxide (rGO)-based polyethyleneimine (PEI) composite (rGO/PEI) was synthesized by utilizing the unique roles of PEI as reducing agent and surface modifier to overcome the above-mentioned drawbacks of graphene. Composites with different graphene oxide (GO):HPEI ratios were used to prepare rGO-high molecular weight PEI (rGO/HPEI). For potential application as hydrogen gas barrier material, rGO/HPEI composites were coated onto the polyethylene terephthalate (PET) substrates through spray coating technique to prepare gas barrier films. Analogous rGO/LPEI (low molecular weight PEI) coated PET film was also prepared. The rGO/HPEI composite-coated films showed dramatic enhancement in hydrogen gas barrier properties and excellent tensile strength with high elongation at break as compared to PET and rGO/LPEI coated PET films.