Elucidation of the Atomic-Scale mechanisms of Friction in Model SAMs and DLC films

The development of micron-sized devices for terrestrial and space applications has prompted the need for protection of the surfaces of these devices. Amorphous carbon films, diamondlike carbon, and SAMs are all possible candidates for the passivation and lubrication of these devices. The fundamental problem associated with controlling friction is a lack of understanding of the underlying atomic-scale processes that govern it. Over the past several years, we have performed extensive molecular dynamics simulations aimed at understanding the atomic-scale mechanisms of friction. We have examined the contact forces present at the interface of a tip and SAMs during sliding. Compression- and shear-induced polymerization have also been modeled in SAMs. In addition, we have done simulations that analyzed the tribological properties of amorphous carbon films with various compositions and of diamondlike carbon films. Some of our recent results will be discussed.