▎ 摘　　要

Two different graphene nanosheets with different oxygen groups' localization were synthesized to investigate their effect on the electrical properties of graphene/epoxy nanocomposite coatings. Graphite natural flakes (NG) and expanded graphite (EG) were used as a carbon precursor to synthesize Edge functionalized (E-GO) and Basal Functionalized (B-GO) graphene nanosheets, respectively. Next, polymer nanocomposite coatings were fabri-cated by dispersing E-GO and B-GO into a waterborne epoxy matrix. Rheology was assisted in evaluating the dispersion state of the nanosheets in the epoxy matrix. B-GO exhibited better performance in network formation which can be related to the similarity of oxygen groups between B-GO and epoxy matrix. Next, the electrical conductivitie values of polymer nanocomposite coatings were measured after in-situ thermal reduction at 225 degrees C. The results indicated that polymeric coatings containing B-GO nanosheets represent higher electrical conduc-tivity values compared to samples containing E-GO nanosheets despite the higher intrinsic electrical conductivity of E-GO compared to B-GO. This can be related to the improved ability of B-GO nanosheets to form an electrically conductive network inside the epoxy matrix. The electrical conductivity value of 0.5 S/m was obtained for polymeric coatings containing 0.8 vol% B-GO nanosheets with percolation thresholds of 0.17 vol%. The improved electrical conductivity can be correlated to the formation of the interphase region between the epoxy matrix and B-GO nanosheets which is the result of the similarity of the oxygen groups' nature in B-GO and epoxy.