Highly conductive polyimide nanocomposite prepared using a graphene oxide liquid crystal scaffold

High loading of aligned graphene filler is effective for fabricating polymer nanocomposites with drastically improved properties, while practical preparation of such composites remains elusive. This paper reports on a method of preparing polyimide (PI, BPDA/PDA) nanocomposites containing highly loaded graphene fillers that are uniformly aligned parallel to the coating substrate in the PI matrix. The highly aligned graphene/PI film was achieved by infiltrating water-soluble poly(amic acid) ammonium salt (PAAS) into the scaffold of the graphene oxide liquid crystal. After thermal treatment, a freestanding reduced graphene oxide/polyimide (rGO/PI) film was prepared with the imidization of PAAS and reduction of graphene oxide. Owing to the excellent mechanical properties of the infiltrated PI, the hardness and modulus of the rGO/PI film were as high as 0.9 GPa and 9.3 GPa, respectively. In addition, the rGO/PI film was highly conductive, with an electrical conductivity of 446 S/m, because of the well-connected electrical pathways of the highly loaded and aligned graphene sheets. (C) 2020 Elsevier Ltd. All rights reserved.