The technique of enhancing adhesion of PFPE (perfluoropolyether) lubricants to the carbon overcoat of magnetic media discs by irradiation with far-UV (185 nm) was reported some time ago.[1] It was later suggested that photoelectrons emanating from the carbon layer was responsible for the observed efficacy.[2] Capture of these low energy electrons by PFPE molecular chains would lead to detachment of a fluoride anion and formation of a radical center on the polymer backbone. Adhesion occurs when the radical center reacts with the carbon layer. Most recently this mechanism was challenged, and photo-cleavage of a CF2O unit from the molecular chain thus generating two radical chain fragments was proposed as the primary happening.[3] In either case the reaction commences at a point randomly selected on the molecular chain. The UV-curing process was not adopted into the production process until recently. The process is now being used for such lubricant mixtures as A20H/Z-dol and A20H/Z-tetraol. In these mixtures, however, an electro- or photo-chemistry involving the phosphazene moiety of A20H appears to play a major role.[4] One negative issue with the far-UV curing process is production of ozone if oxygen is present.

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