NANOMETER-SCALE MAPPING OF CHEMICALLY DISTINCT DOMAINS AT WELL-DEFINED ORGANIC INTERFACES USING FRICTIONAL FORCE MICROSCOPY

This paper demonstrates the ability to map chemically distinct domains at nanometer length scales using frictional force microscopy (FFM). The basis of this characterization is the dependence of the frictional interactions on the identity of the chemical functional groups at the outermost few angstroms of microscopic contacting areas, i.e., the surface free energies. Such a dependence is confirmed by characterizations of the frictional force between a variety of end-group-derivatized alkanethiolate monolayers deposited at both gold-coated sample substrates and gold-coated FFM probe tips. Coupled with this dependence, we show that the composition of chemically distinct domains at partially formed bilayer structures can be mapped at a spatial resolution of similar to 10 nm, with the image contrast governed by the surface free energies of the microscopic contacts. Opportunities presented by these findings are briefly discussed.