Abstract
Depletion and replenishment characteristics of molecularly thin PFPE lubricant film coated over magnetic disk were studied through the pin-on-disk sliding test using magnetic disks coated with hydrogenated diamond-like carbon and a semi-sphere glass pin. Depletion and a pile of the lubricant after the sliding test and recovery process towards original flat surface were measured using OSA (optical surface analyzer). A peculiar phenomenon was observed wherein the replenishment function of lubricant was stalled or weakened when the residual film thickness after depletion nearly equaled to a monolayer of PFPE molecules. This phenomenon can be attributed to the fact that the polar component of surface energy takes a local minimum just at a film thickness equivalent to a monolayer of polar molecules.
