Friction is involved in many different processes on different length scales, such as motions of joints, writing on a blackboard and the occurrence of earthquakes. Empirical theories have been developed in past centuries by Leonardo da Vinci, Amontons and Coulomb among others, founding the discipline of tribology. However, a general description of friction has not been achieved so far.
Fundamentally, friction is defined as the resistance acting against the motion of two bodies sliding past each other. In order to properly understand friction, we have to extend our knowledge to the molecular scale. In particular, the amount of energy dissipated in friction depends on many parameters such as the shape of the asperities, elasticity of interacting materials and type of medium between those materials sliding past each other.
Atomic force microscopy (AFM)-based methods offer the unique opportunity to detect frictional forces with piconewton resolution at a spatial scale from micrometers to Angstrom. Wear can be quantified by imaging with AFM. Furthermore, for triboelectric studies surface potentials can be obtained via Kelvin probe force microscopy with millivolt accuracy. Thus, AFM-based techniques help us to understand friction at the molecular scale, which stimulates the field of nanotribology and finally allows us to design future energy-efficient and wear-resistant devices.
Register for the special nanotribology session at NSFE 2021 here: www.nanoscientificforum.com