Multiscale study of influence of interfacial decohesion on piezoresistivity of graphene/polymer nanocomposites

A multiscale strategy is proposed to study the role of interfacial decohesion on the piezoresistive properties of a graphene/polymer nanocomposite. The piezoresistive effect is a change in the electrical resistivity when mechanical strain is applied. First, a cohesive zone model is identified by atomistic simulations. This cohesive zone model enriches imperfect interfaces, which model graphene sheet, at mesoscale in our continuum mechanical model. This nonlinear mechanical model is used to generate deformed representative volume element to study the influence of strain and interfacial decohesion on the conductivity of graphene/polymer nanocomposites. The effective conductivity is studied with an electric continuum model at mesoscale that incorporates the tunneling effect. A conductor-insulator transition is observed for elongations above 2% for graphene volume fraction just above the percolation threshold. The transition appears for an elongation of 8% instead of 2%, when the interfacial decohesion is neglected.