Humans have always tried to find ways to reduce friction in order to minimize dissipation when moving objects or parts. One obvious way to achieve this goal, is to swap sliding with rolling (just think about ball bearings or, simply, the wheel). While apparent on a macroscopic scale, whether rolling can be initiated at the microscale and how it is characterized remain open questions.
In this talk, I will introduce the concept of boundary lubrication, revisit Amonton’s friction laws and talk about sliding and rolling contacts. I will then report on an atomic force microscopy method we have recently developed to measure rolling friction of individual microparticles and show that, by combining this method with mechano-sensitive polymeric coatings, we can reveal fundamental differences in the microscopic nature of sliding and rolling friction.