Bonding, degradation, and environmental effects on novel perfluoropolyether lubricants

Tribological properties of perfluoropolyether (PFPE) lubricants with different end groups, applied on Si(l 00) substrate, are investigated. The PFPE lubricant with two hydroxyl groups at each end of the molecular chain (Z-TETRAOL) and another lubricant with a hydroxyl group at one end and a cyclotriphosphazene group at the other end, respectively (A20H) (used by itself and mixed with Z-DOL) are studied and compared with conventional PFPE lubricant with one hydroxyl group at each end (Z-DOL). The thermal bonding in terms of thickness of the lubricants is investigated using an ellipsometer. For the first time, the degradation of the lubricants is investigated using a mass spectrometer in high vacuum. The environmental effects on the lubricants are studied in high vacuum, in argon, and in air with various humidity levels. It was found that the durability of Z-TETRAOL, A20H, and Z-DOL+A20H is better than that of Z-DOL in various environments. (c) 2005 Elsevier B.V. All rights reserved.