SURFACE-POTENTIAL OF THIN PERFLUOROPOLYETHER FILMS ON CARBON

Perfluoropolyether (PFPE) films for lubrication of thin film magnetic recording media are made progressively thinner and their physical prop erties are increasingly dominated by molecular interactions with the c arbon overcoat. Surface potential measurement is one of a few techniqu es to study the interaction of ultrathin films with surfaces, A scanni ng Kelvin probe apparatus with spatial resolution of 100 microns and p otential sensitivity of 0.5 mV was employed to study the surface poten tials of linear and branched PFPE films with methyl, hydroxyl, phenyl ester, and carboxylic acid end groups on amorphous hydrogenated carbon surfaces. The surface potential is dominated by polar groups rather t han the PFPE monomers, Application of the scanning surface potential t echnique to measure the migration of PFPE films is also shown. (C) 199 7 American Institute of Physics.