Nanoindentation characterization of nanocomposites coating based on graphene and siloxane matrix deposited by dielectric barrier discharge plasma

•Thin films of graphene/siloxane nanocomposites were deposited by aerosol injection.•Deposition was performed in a one-step process in an atmospheric pressure plasma.•The viscoelastic behavior of nanocomposite was evaluated by the nanoindentation test.•Graphene incorporation enhanced the mechanical properties of the nanocomposite. Hexamethyldisiloxane (HMDSO)/Graphene nanosheets (GNs) nanocomposite coatings were deposited by a dielectric barrier discharge at atmospheric pressure. Commercially available GNs were incorporated into HMDSO precursor at different concentrations up to 2 wt%. The nanocomposite coatings were analyzed using scanning electron microscopy (SEM) and nanoindentation test. Based on SEM images, it was found that the GNs were well distributed and dispersed in the plasma polymerized hexamethyldisiloxane (ppHMDSO) matrix with no significant agglomeration. The results of nanoindentation tests performed with the continuous stiffness measurements mode showed an increase in the hardness and reduced Young's modulus with the increase of graphene nanosheets percentage. The maximum increase was two orders of magnitude for 2% GNs/ppHMDSO nanocomposite coatings compared to the homopolymer ppHMDSO. Furthermore, the creep compliance analysis showed that the nanocomposite coatings exhibited a viscoelastic behavior compared to the plasma polymer homopolymer. [Display omitted]