Mechanical properties of free-standing graphene oxide

The mechanical properties of free-standing graphene oxide (GO) films were investigated using nanoindentation on a dynamic contact module (DCM) system. The Young's modulus, stiffness, and ultimate strength of thin films were evaluated. Nanoindentation measurements were combined with the DCM to evaluate the mechanical properties of thin films and to predict the crack length and critical energy. Electrophoretically deposited GO film, 50 ~ 60 nm in thickness, was found to have a Young's modulus of 695 ± 53 ~ 697 ± 15 GPa. The critical energy values for 50- and 60-nm-thick films were 0.142 ~ 0.201 and 0.479 ~ 0.596 J/m², respectively. Nanoindentation combined with the DCM can thus be used to obtain the mechanical properties and critical energy of thin films.