Probing Friction At Nanoscale With Graphene Nanoribbons

Graphene is by far the simplest 2-d material and has received significant scientific attentions due to its combination of remarkable mechanical, chemical, thermal and electrical properties. In this thesis, we investigate the interaction between graphene nanoribbons (GNRs) and graphene substrate with the use of molecular dynamics method (MD) to probe friction at nanoscale. The results of this thesis can provide guidance for designing nano-devices nano-composite structures, etc.Firstly, the dragging processes of GNRs with different geometries between two flat graphene substrates at low temperature are simulated, where we find that the friction is strongly correlated with the width of a GNR. Simulated friction force appear to be consistent with other experiments. The dragging processes of GNRs on different waved monolayer substrates at room temperature are also investigated, where frictional forces exhibit a two-phase dependence on wave lengths. The results are subsequently discussed with different theories.We have also considered structures consisting of monolayer or multi-layer GNRs between two graphene substrates. Waves are created within the structures. In one case, we find the friction of GNRs is similar to that of double-walled carbon nanotubes. In another case, we find that the friction force gradually rises to a high level, which can be due to the effect of pretension. In addition, we also simulate the swinging and migration of GNRs on graphene substrate, which may be relevant to the migration or reorientation of biological cells on elastic matrixes.