Tribology Studies of Organic Thin Films by Scanning Force Microscopy

Abstract

AbstractUsing the micro-contact printing method we prepared patterned self-assembled monolayers (SAMs) consisting of methyl-terminated alkanethiols of different chain lengths. The samples were characterized using lateral force microscopy (LFM) and the force modulation technique (FMT). In general, higher friction is observed over the short chain regions than over the long chain regions when a low or moderate load is applied to the scanning force microscopy (SFM) tip. For such cases the high friction (short chain) regions are also “softer” as measured by FMT. At high loads, a reversal of the image contrast is observed and the short chain regions show a lower friction than the long chain regions. This image contrast is reversible upon reduction of the applied load.