Kinetic and static friction between alumina nanowires and a Si substrate characterized using a bending manipulation method

The kinetic and static friction forces between Al2O3nanowires (NWs) and a Si substrate were simultaneously determined by the use of bending manipulation, which bent a NW into a “hook” shape, and then let it recover elastically. An analytical model was developed to estimate the kinetic friction force based on the hypothesis that part of the elastic energy stored in the bent NW was consumed by the work of the friction during recovering. The static friction force was also calculated using force equilibrium. Finite element analysis and experimental testing were performed to verify the analytical model. The kinetic and static friction forces per unit area obtained were in the ranges of 1.16–3.4 MPa and 0.68–2.7 MPa, respectively, which agree well with most of the values reported previously for NWs or nanoparticles on flat substrates. It was also found that the NW size had no apparent effect on the interfacial shear stress.