Molecular Dynamics Simulation on Friction Properties of Textured Surfaces in Nanoscale Rolling Contacts

The dimension of components in micro/nanoelectromechanical systems (MEMS/NEMS) has been reduced to nanometer. Due to size effects at nanoscale, there is severe adhesion effect in the MEMS/NEMS. As a result, improving friction behaviors has become one of the most important ways for MEMS/NEMS to prolong their lives. At macroscale, friction forces of rolling contacts are lower than those of sliding contacts, while there are no comprehensive studies on the friction performance of the nanoscale rolling contacts. Molecular dynamics simulation is used to investigate the friction performance of nanoscale rolling contacts in this work. The dependence of average friction forces on indentation depth and tip size is investigated. The average friction force of the rolling contact is much lower than that of the sliding contact. Increasing the indentation depth causes the increase of the average friction forces, while the tip radius shows little influence. Furthermore, by creating textures with different widths on upper and lower substrates, their influence on the rolling contact performance is studied. Compared with a smooth surface, the textured surfaces can improve the friction properties of nanoscale rolling contacts. The texture width, texture depth, and texture shape influence the friction behaviors greatly.