Engineering the Interface of Interfacially-Locked Graphene in Electrically Conductive Poly (ethylene furanoate)/Polyethylene (PEF/PE) Blends

Designing conductive nanocomposites by localizing/trapping a conductive nanofiller at the polymer/polymer interface is quite challenging and considered very dynamic. In this work, the interface developed in poly(ethylene furanoate)/polyethylene (PEF/PE) blends is studied and evaluated for strategic localization of graphene at the interface. The trapping of graphene at the interface was confirmed by extraction of individual components as well as a sharp increase in the electrical conductivity of the PEF/PE/graphene nanocomposites. The sequence of mixing PEF, PE, and graphene showed significant effects on graphene's localization. The inclusion of graphene reduced the characteristic domain size by inducing compatibility in PEF/PE. The PEF/PE interface acts as an energy well that does not allow diffusion of graphene nanosheets into or away from the interface by annealing at high temperatures. Furthermore, adding a compatibilizer affected conductivity negatively, attributed to the altered morphology in blends. The PEF/PE/graphene nanocomposites achieved a low percolation threshold of 0.97 vol%, whereas electrical percolation in PEF/GNP and PE/GNP nanocomposites was observed at 6–7 vol%. A 3D graphene network was confirmed in PEF/PE/GNP nanocomposites via power-law conductivity model. This is the first report on electrically conductive PEF-blends highlighting the potential of interfacially-localized graphene in optimizing the multifunctional properties of bio-based PEF.