In disk drives of current generation, the thickness of the disk lubricant has been reduced to the level of a sub-monomolecular film. For a mono- or a sub-monomolecular film of a perfluoropolyether terminated with a primary hydroxyl unit at both ends, each lubricant molecular chain is chemically bound to the carbon substrate at both termini, and if it has a hydrocarbon sector inserted at its center, the hydrocarbon sectors would assemble at the top of the film. They are thus poised most aptly to react as a Lewis base (an electron donor) to the Lewis acid centers on the slider thus abating the Lewis acid-catalyzed lubricant degradation.
