2, University of Arizona, Tucson, Arizona, United States
Recent advances in the ability to to synthesize metal-ion coagulated graphene oxide (GO) colloidal dispersions has provided new avenues for fabrication of GO and reduced graphene oxide (rGO) based thin films and membranes for applications as mechanically robust coatings as well as anti-corrosive protective layers. To this end, a fundamental study on the interplay between composition, thermal stability and mechanical properties of metal-GO as well as metal- rGO thin films was carried out employing multiscale models that couple molecular dynamics simulations in conjunction with mesoscale techniques such as finite element methods (FEM) and peridynamics (PD). Transition metals such as iron, vanadium and nickel were considered in this study. The investigations reveal that for a given concentration of metal ions, iron containing GO and rGO films demonstrate higher elastic modulus as well as a marked increase in tensile and shear strength, whereas incorporation of nickel and vanadium ions lead to a decrease in mechanical strength of the resulting GO/rGO films. Furthermore, the degree of orientation mismatch between neighboring GO/rGO grains was shown to have a significant effect on the tensile strength, implying a crucial role of the interfacial structure on the mechanical response of the thin films. Valuable lessons learned from this work provide important insights into the design and development of GO and rGO films for targeted mechanical and chemical applications.