Z-DOL and carbon overcoat: Bonding mechanism

Abstract

It has been postulated earlier that the bonding between Z-DOL and sputtered carbon occurs when a hydrogen atom is transferred from a hydroxyl end group of Z-DOL to a dangling bond site shielded inside the sp3 type (diamondlike) granules of the carbon film, and the Z-DOL moiety is linked to the carbon as an alkoxyl group, HO-CH2-CF2-O-(-CF2-CF2-O-) m-(-CF2-O-)n-CF2 -CH2-O-[carbon]. The postulated mechanism predicts that the Z-DOL bonding should occur spontaneously if freshly sputtered carbon were exposed to Z-DOL molecules without prior exposure to air, and that, for disks lubricated with Z-DOL, there would be less hydroxyl hydrogens, and there would exist the alkoxyl units depicted above. A recent reported result on vacuum deposition of Z-DOL (without prior exposure to air) clearly revealed the predicted spontaneous bonding, and analyzes by TOF-SIMS of disks lubricated with Z-DOL demonstrated the predicted decrease of the hydroxyl hydrogen and emergence of the predicted alkoxyl units as the bonding fraction of Z-DOL increases.