Perfluoropolyethers with dialkylamine end groups: ultrastable lubricant for magnetic disk application

It has been shown earlier that addition of XIP (partially fluorinated hexaphenoxy cyclotriphosphazene) to the lubricant Z-DOL markedly increases the durability of the magnetic disk system. Its efficacy has been attributed to the strong nucleophilic property of the triphosphazene ring. It follows that perfluoropolyethers terminated with nucleophilic end groups should exhibit a durability comparable to that of the Z-DOL/XIP mixture. To this end perfluoropolyethers with dialkylamine end groups were conceived and synthesized as better alternatives to Z-DOL or to the Z-DOL/XIP mixed system. Examination of the newly synthesized lubricant revealed that (1) perfluoropolyethers with dialkylamine end groups are resistant to the degradation process catalyzed by Lewis acid (e.g., aluminum oxide), (2) disks lubricated with these lubes have durability significantly better than those lubricated with Z-DOL, (3) in the drive system with disks lubricated with these lubes, the issue of the silicon oxide formation from siloxane contaminant is effectively contained (owing to the absence of degraded lube), and (4) the HDI system with disks lubricated with these lubes performs well even in the most aggressive atmospheric condition, i.e., nitrogen with 0% relative humidity.