Effects of the functionalized graphene oxide on the oxygen barrier and mechanical properties of layer-by-layer assembled films

An effective method to fabricate high-performance oxygen gas barrier films by alternately stacking negatively charged graphene oxide (GO) and positively charged aminno-ethyl-functionalized GO (AEGO) on PET substrates was suggested. The GO was prepared by the Hummer's method using natural graphite powder and the AEGO was synthesized by a carbodiimide reaction of the GO. High resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the introduction of functional groups of GO and AEGO. GO/AEGO/GO layers on a PET film were formed through spray coating method. The gas barrier and mechanical properties of the film were examined. One layer of GO/AEGO/GO stacked film coated on a PET substrate showed an oxygen permeability of 0.01 cc/m2 day atm, which is 103 times lower than that of pure PET. The results corresponding to tensile strength and modulus of the film revealed an increase of approximately 61 and 41% compared to those of pure PET, respectively.