Ultra-low gas permeable cellulose nanofiber nanocomposite films filled with highly oriented graphene oxide nanosheets induced by shear field.

Graphene oxide nanosheet/cellulose nanofiber (GONS/CNF) nanocomposite films with ultra-low gas permeable property were fabricated through layer-by-layer coating and hot pressing method. XRD results showed that GONS was completely exfoliated and well dispersed in CNF matrix. The images of SEM and GI-WAXS manifested that the exfoliated GONS was highly oriented along the film direction under a strong external shear flow field. Such unique structure endows GONS/CNF nanocomposites with ultrahigh oxygen barrier property and good water vapor barrier performance. With only 3.66 vol% GONS, the oxygen permeability coefficient of CNF film decreased by about 4 × 104 times, from 5.5 × 10-13 to 1.4 × 10-17  cm3 cm·cm-2 s-1  Pa-1. Meanwhile, the tensile strength and Young's modulus of the CNF film were respectively enhanced by 2 and 57 times. Furthermore, the thermal stability of CNF film was also improved with the incorporation of GONS.