Intrinsic structure and friction properties of graphene and graphene oxide nanosheets studied by scanning probe microscopy

In this paper, atomic structure of single-layered graphene oxide (GO) and chemically reduced graphene oxide (CRGO) nanosheets was investigated using atomic force microscopy and scanning tunneling microscopy (AFM and STM). Furthermore, friction properties of the graphene and GO nanosheets were studied by frictional force microscopy (FFM). STM imaging provided direct evidence and the morphology was influenced by oxygen-containing groups and defects. The atomic scale structural disorder in a hexagonal two-dimensional network of carbon atoms changes the surface condition, which also caused the frictional property variations of the samples.