Nanoscale Mapping of Frictional Anisotropy

Friction hodographs contain all the information related to the intensity and symmetry of the friction phenomenon. We show how an atomic force microscope can be used to collect friction hodographs at the nanoscale and how to carry out data interpretation to unravel the friction–surface structure relationship. As a model system, we analyzed the basal plane of orthorhombic β-alanine single crystals, and interpreted the data in terms of a constitutive model of orthotropic friction with slip direction-dependent friction coefficients.