Highly Efficient Three-Dimensional Gas Barrier Network for Biodegradable Nanocomposite Films at Extremely Low Loading Levels of Graphene Oxide Nanosheets

A simple and facile method was proposed to successfully build a three-dimensional (3D) gas barrier network of graphene oxide nanosheets (GONSs) in the biodegradable poly(lactic acid) (PLA) matrix, in which GONSs were first self-assembled on the surface of PLA microspheres and then preferentially distributed at the interface of PLA domains. Polyethylene oxide was introduced as a flow accelerator and interfacial adhesive for favorable interfaces. As a result, the as-prepared PLA nanocomposite films exhibited a significant enhancement in barrier performance with similar to 78.6% reduction in the O-2 permeability coefficient at a low GONS loading of 0.0344 vol %. The modified Bharadwaj model by introducing an effective stacking factor indicated an efficient assembly of GONSs in the form of edge-to-edge stacking. The new insight into the relationship between the stacking efficiency of nanoplatelets and barrier performance provides a valuable clue in developing high-barrier polymer nanocomposite films.