Chemical Properties of Fomblin® Perfluoropolyether Lubricants with Arylalkyl Groups on Hard-Disk Media

Abstract

The chemical characteristics of perfluoropolyether lubricant films, which have arylalkyl groups at both ends of the main chain, were studied on hard-disk media. It was found by time-of-flight secondary ion mass spectroscopy (TOF-SIMS) that 94% of the functional groups of AM3001, (3,4-dioxomethylenephenyl)methyl, were eliminated from the main chain on a disk surface after a 672 h exposure, even in a regular clean room of 23°C and 55% RH. Regarding the lubricants synthesized by the authors, LUB-A having a benzyl functional group lost 35% of its functional group after a 768 h exposure. The 3-phenylpropyl functional group of LUB-B was not eliminated even after a 672 h exposure. It was suggested that hydrolysis easily occurred at the ether linkage between the main chain and the functional group, and removed the functional group from the main chain because the benzyl cation was chemically stable. The new lubricant having a 3-phenylpropyl functional group, which is chemically stable and does not decompose on a disk surface, was developed and proposed for use with hard-disk media.