Effect of annealing temperature on the mechanical properties of flexible graphene films

Free-standing graphene films (GFs) as functional materials require high mechanical performance for a convenient industrial processing. GFs were prepared from graphene oxide films by annealing temperatures from 1300 to 1700 °C, and were characterized by AFM, XRD, SEM, Raman spectroscopy and mechanical testing. Results indicate that the samples have a maximum tensile strength and fracture strain of 22.41 MPa and 2.44%, respectively and a minimum thermal conductivity of 744 W m−1 K−1 for an annealing temperature at 1500 °C. This is related to physical interlocking which results, from surface wrinkles of the graphene layers.