▎ 摘　　要

A graphene film was synthesized using chemical vapor deposition and then transferred to a flexible poly(ethylene terephthalate) (PET) substrate. The nanomechanical properties of the graphene/PET (G/PET) system were investigated by nanoindentation. The hardness (H) and reduced modulus (E-r) of PET and G/PET were calculated using the Oliver-Pharr. method with corrections for creep and material pile-up around the contact. The H and E-r of the G/PET were 97% and 16% higher respectively than on the PET substrate. The increase in E-r can be attributed to the high in-plane elastic modulus of graphene, the smaller increase in E-r than H merely reflecting the far-field nature of the elastic stress field compared to the plastic stress field. The creep behavior of the PET is strongly hindered by the presence of the graphene overlayer. A simple volume contribution model was adopted to calculate the elastic modulus of the graphene overlayer and the computed values were of the right magnitude for graphene film. (C) 2012 Elsevier Ltd. All rights reserved.