Stability Analysis of Ultra-Thin Lubricant Films with Chain-End Functional Groups

Abstract

The thermodynamic stability of ultra-thin perfluoropolyether (PFPE) films is examined. The model used in this paper incorporates a layered structure due to polar interaction at the endgroups and provides the stability criteria as a function of film thickness, the surface/interfacial energies of PFPEs and substrates, and molecular weight. The surface energies of PFPEs were obtained from measured contact angles and separated into non-polar and polar components using Fowkes' method. The stability of PFPE films is examined via a diagram constructed from the measured surface energies of PFPEs and hydrogenated carbon substrate.