ABSTRACT
The search for a truly ultra-thin (only a few to tens of nm thick) coating on solid substrates has gained importance in recent times because of the growth in microsystems technologies. Historically, Si has been the mainstay material for many microsystems where interfacial cyclic contacts and sliding are encountered, for example in microelectromechanical systems (MEMS). Si is known for poor tribological performance as it wears out easily when in dynamic contact with itself or with another similar material due to its strong hydrophilic nature and brittle mechanical response to contact stress. Hence, tribology of Si surface is a technologically very important area of research. In this chapter, a review of the recent developments in the area of tribology (friction, adhesion and wear properties) of self-assembled monolayers (SAMs) on Si is presented. Further, examples of the studies conducted on SAMs overcoated with peruoropolyether (PFPE) are demonstrated to elucidate the importance of a liquidlike lm on SAMs for enhancing the wear life of Si surfaces. PFPE overcoatedSAMs on Si have reduced friction and adhesion vis-à-vis only SAMs or bare Si surfaces, and have shown greater improvement in wear durability. These ultra-thin lms can nd applications in a variety of Si made components and devices.
