Physical properties comparison of two-dimensional materials: MXene and graphene oxide

Abstract Two-dimensional (2D) nanomaterials are promising for many different applications. Therefore, detailed characterization and knowledge of their properties are needed. This work focused on graphene oxide (GO) and a new 2D nanomaterial, MXene, type Ti 3 C 2 T x . The spray coating method was used to create thin GO and MXene films on a glass substrate. Their composition was characterized by X-ray photoelectron spectroscopy. Scanning probe microscopy (SPM) imaging and surface free energy calculation confirmed the homogenous coating of the substrate. The mechanical properties of the prepared films were measured by nanoindentation. The elastic modulus was independent of the film thickness; it was approximately 89 GPa for the MXene samples and approximately 100 GPa for the GO samples. Lower hardness values were determined for thicker films: 10.5 GPa for 5-layer MXene vs. 7.5 GPa for 10-layer MXene and 13.0 GPa for 5-layer GO vs. 9.8 GPa for 10-layer GO. Contact angle measurements and surface energy calculations were performed for all prepared films with 5 or 10 layers. MXenes oxidize on air over time, and the highly conductive Ti 3 C 2 T x structure changes to less conductive titanium oxides. The aging of MXene was studied by monitoring the MXene film conductivity within two months, which showed a decrease, but the 10-layer films were more stable than the thinner 5-layer films.