XPS study on the perfluoropolyether derivative lubricating film on hard disk

The physical and chemical structure of the lubricating film (commercial name: Z-DOL) on hard disk were investigated. The various radicals in the chemical structure of a lubricant molecule were found to be identifiable from the relevant XPS spectra of C_ls; while the thickness of the lubricant film was determined from the peak intensity ratio of O_ls(C-O) with respect to the protective layer CN_x on the hard disk to that in perfluoropolyether (Radical F-O). It was found that the film thickness is variable within a range of 1.5-6.0 nm depending on the process for preparing the lubricating film on the hard disk.