Adhesion and friction behavior on magnetic disks with ultrathin perfluoropolyether lubricant film having different end-groups measured using pin-on-disk test

In this study, we prepared some kinds of lubricants with different numbers of a hydroxyl end group (Z-03, Z-dol, Z-tetraol, and Z-TMD) and measured the adhesion and friction forces on the disks for different lubricant thicknesses. We successfully obtained these forces as a function of lubricant film thickness. The adhesion and friction forces were smallest on the disk with Z-03; the adhesion force was largest on disks with Z-dol, and the friction force was largest on disks with Z-TMD. Z-03 has no hydroxyl end group; hence, this was assumed to be the reason why Z-03 showed the smallest adhesion and friction forces relative to the other lubricants with hydroxyl end groups. The friction force roughly depended on the lubricant coverage or mobile lubricant thickness in the lubricants with hydroxyl end groups.