Microtribological study of perfluoropolyether with different functional groups coated on hydrogen terminated Si

Friction and wear properties of different perfluoropolyether (PFPE) films with and without hydrogen termination on Si (Si-H) were studied using a ball-on-disk tribometer. The physical and chemical properties of the films were evaluated using contact angle measurement, atomic force microscopy and X-ray photoelectron spectroscopy. Coating of PFPEs onto bare Si has lowered the coefficient of friction (from 0.6 for Si to ∼0.05 with PFPE) and enhanced the wear durability (20,000 times) in comparison with those for bare Si which failed immediately. The introduction of hydrogen termination onto Si prior to PFPE coating has further increased the wear durability of PFPE with different functional groups several times (>5 times) under a normal load of 30 mN and a sliding speed of 0.052 m/s.

► Influence of hydrogen termination of the Si substrate on the tribological properties of PFPE films. ► H-termination of the Si surface prior to PFPE coating has increased the wear durability by several orders when compared to PFPE coating onto untreated Si. ► H-termination on Si is a simple and cost-effective means to modify the tribological properties of Si.