Buff/wipe effects on the physicochemical properties of perfluoropolyether nanoscale thin films

Buff/Wipe (B/W) process is commonly used in disk drive manufacturing to remove the particles and asperities on the lubricated disk surface. In this paper, we investigated how B/W process impacts the physicochemical properties of perfluoropolyethers (PFPE) nano-films through the study of surface energy and bonded ratio. Two-liquid geometric method was used to analyze the surface energy of nonfunctional PFPE, i.e., Z03, and functional PFPE, i.e., Zdol, lubricated media before and after B/W process. It was found that the dispersive surface energy of Z03 films greatly decreased after B/W, which was more significant in the submonolayer regime. In addition, the bonded ratio slightly increased. However, B/W effect on the surface energy and bonded ratio was not detected for Zdol films. It is hypothesized that nonfunctional PFPE behaves liquid-like on the carbon overcoat due to the weak interaction between lubricant and overcoat. External mechanical stress as applied with B/W can change the conformation and increa...