Abstract

The atomic force microscopy (AFM) is a versatile instrument that undoubtedly contributes to the development of the nanosciences. This chapter deals with a new technological breakthrough based on the AFM to study nano-tribology: the circular-mode AFM (CM-AFM). It consists in modifying the electronics of the AFM to generate a relative circular displacement of the AFM tip/sample contact. Unlike the traditional AFM modes, the CM-AFM allows performing friction force measurements in a quasi-stationary regime with a high sliding velocity (higher than 1mm/s). Advantages and limitations of the CM-AFM are discussed. Finally, applications of the CM-AFM for investigating friction mechanisms of hydrophilic and viscoelastic surfaces, nano-wear mechanisms and mechanical properties of cell membranes are reported.