Surface energy and adhesion of perfluoropolyether nanofilms on carbon overcoat: The end group and backbone chain effect

In this paper, we have investigated the surface energy and adhesion of one functional PFPE (Zdol) and two series of nonfunctional PFPEs (Z and D) on carbon-overcoated disk surfaces. The effects of end group functionality, backbone chain flexibility, molecular weight, and film thickness were systematically examined. Our results indicated that nonfunctional PFPEs have weak attraction with carbon overcoat. However, due to backbone chain effect, Z has slightly stronger attraction than D. Based on the surface energy analyses and bonded thickness results, schematic bonding models were proposed, which indicate strong hydrogen bonding/ordered packing structure/low mobility for functional PFPE films and weak attraction/less-ordered packing structure/high mobility for nonfunctional PFPE films. (C) 2006 American Institute of Physics.