Identifying the Mechanisms of Polymer Friction through Molecular Dynamics Simulation

Mechanisms governing the tribological behavior of polymer-on-polymer sliding were investigated by molecular dynamics simulations. Three main mechanisms governing frictional behavior were identified. Interfacial brushing of molecular chain ends over one another was observed as the key contribution to frictional forces. With an increase of the sliding speed, fluctuations in frictional forces reduced in both magnitude and periodicity, leading to dynamic frictional behavior. While brushing remained prevalent, two additional irreversible mechanisms, combing and chain scission, of molecular chains were observed when the interfaces were significantly diffused.