Revealing the interrelation between hydrogen bonds and interfaces in graphene/PVA composites towards highly electrical conductivity

Conductive graphene/polymer nanocomposites have drawn particular attention owing to their great promising in various environmental and energy-related applications. A percolation theory based on variation of conductive filler fraction has been demonstrated as the central guide for their fabrications. However, it typically fails in some special cases since the assumption has ignored the effect of interfacial interaction between the conductive nanofillers and the material matrix. Herein, we employ a graphene/poly(vinyl alcohol) model to study the effect of interfacial interaction on their electrical conductivity by using two types of graphene with different oxygen content. We further demonstrate cage effect as a critical role on their conductivities, which arise from the interfacial hydrogen bonding interaction between the graphene nanofiller and PVA matrix. A cage effect modified percolation theory gave an excellent match with the experimental data. Notably, such cage effect can be effective alleviated by applying a hot drawing treatment, thus achieving a higher electrical conductivity. As such, we successfully fabricate a graphene/PVA composite with a superior electrical conductivity up to 25 Sm-1 at a 6.25 wt% graphene. Its excellent electronic stability after multiple bending operations was also verified in a laboratory prototype device to confirm its suitability for flexible electronics.