Structural modulation of graphene–polyimide interfaces below pyrolysis temperature under electrothermal treatment

In the area of carbon-based thin films, graphene/polyimide conductive films display remarkable heat resistance and mechanical properties, making them a valuable resource for utilisation in a multitude of manufacturing and living contexts. Nevertheless, modulating the interfacial structure between graphene and polyimide represents a significant challenge in the pursuit of enhancing the conductivity of the composite films, due to the elevated initial temperature of polyimide pyrolysis (exceeding 600 °C). To develop it, this study found that polyimide could undergo chemical bond breaking and atomic rearrangement at around 500 °C, when subjected to an applied electric field in graphene/polyimide films. A series of characterisations showed that the graphene/polyimide film formed a new interfacial structure under electrothermal treatment, which enhanced the electron transport capacity and increased its conductivity from about 1497.01 s m⁻¹ to about 2688.17 s m⁻¹, with an increase of about 79.57%. This study would provide the possibility of modulating the structure of polyimide below the pyrolysis temperature, as well as a feasible idea for transferring the properties of graphene into the polyimide matrix.