Conformation of ultra-thin PFPE lubricant with different structure on magnetic disks - direct observation and MD simulation -

Abstract

Three kinds of PFPE lubricants (Z-tetraol, TA-30, D-4OH) with different molecular structures were coated on the magnetic disks, then we confirmed the film conformation of these lubricants on the disks by the AFM with the fluoride coated probe. The film conformations of these lubricant films were different. Z-tetraol showed highest film thickness and lower coverage in these lubricants. TA-30 showed double layers structure and highest coverage. D-4OH showed monolayer and higher coverage than Z-tetraol. These observed results agreed with the molecular dynamics simulation results. In this simulation, TA-30 showed highest coverage and lowest thickness, because TA-30 molecule did not form the random coil shape, and it adsorbed rigidly on the disk surface. Z-tetraol adsorbed as the random coil shape. D-4OH adsorbed as the spiral shape.