Thin Film Lubrication Based On PDMS Networks

This study reports on the interfacial friction and wear properties of surface-tethered cross-linked polymer thin films. We have previously shown that thin, two-tiered films produced by covalently bonding polydimethylsiloxane (PDMS) networks to self-assembled monolayers manifest the lowest friction coefficient (μ = 0.0039) recorded for a dry lubricant film. To determine the origin of this result, we introduce controlled amounts of pendant and free PDMS chains into optimal PDMS network films, and explore their effects on interfacial friction, wear, and film modulus. Using a combination of lateral force microscopy, nanoindentation, and rheology experiments we determine the molecular-scale processes responsible for lubrication properties of thin PDMS films.