AN ADSORPTION OF PERFLUOROPOLYETHERS ON SIO2 SURFACES FOR THIN-FILM MAGNETIC DISK OVERCOATS
Author: Yanagisawa, M
HERO ID: 3860678
Perfluoropolyethers (PFPEs) have been widely used as an excellent lubricant on magnetic disks. Sol-gel . . .
Perfluoropolyethers (PFPEs) have been widely used as an excellent lubricant on magnetic disks. Sol-gel SiO2 has been applied as a protective overcoat for plated magnetic disks. Adsorption of PFPEs on the surface of a protective overcoat is an important issue in evaluating lubrication characteristics, such as coefficient of friction, wear resistance, volatility, spin-off, etc. for magnetic disks. Molecular configuration and magnitude of adsorption between lubricants and protective overcoats were measured, using various analytical methods, i.e., diffuse reflectance IR spectroscopy, polarization reflection IR spectroscopy, refractive index analysis, flow micro-calorimetry, etc. Functional groups in PFPE molecules adsorb to silanol groups on the sol-gel SiO2 surface. The main chain of PFPE molecule orients parallel to the sol-gel SiO2 surface. The thickness of adsorbed PFPE agrees well with the diameter of the PFPE main chain. The heat of adsorption increases with increasing hydrophilic affinity of functional groups. The heat of adsorption decreases with increasing baking temperature of sol-gel SiO2, which corresponds to the decrease in silanol group density.