Rolling and Spinning Friction Characterization of Fine Particles using Lateral Force Microscopy based Contact Pushing

Here, we have utilized Lateral Force Microscopy (LFM) based mechanical pushing of micro/nano-objects to study adhesion and friction characterization at the micro/nanoscale. Continuum micro/nano-friction models for particle rolling, spinning and sliding cases are discussed for general particle-substrate interfaces. A rolling resistance model using the Double-Hertz model is devoloped for such general interfaces. Using the friction models, the effect of work of adhesion, effective Young’s modulus, and contact radius at the particle-substrate interface are studied in detail. Combining friction models with experimental particle pushing vertical and lateral force data, the critical frictional interface parameters such as critical rolling distance and the interfacial shear strength are measured for a polystyrene particle and glass substrate interface. Results show that the critical rolling distance varies with the particle radius, and it is measured to be 42 nm, 84 nm, and 128 nm on average for 5 μm, 10 μm, and 15 μm radius particles, respectively. Next, using the particle spinning experimental data, the interfacial shear strength of the particle-substrate interface is measured as 9-15 MPa.