Functional Group Imaging by Adhesion AFM

Recently developed adhesion atomic force microscopy was used as a technique to map the spatial arrangement of chemical functional groups at a surface with a lateral resolution of 20 nm. The ratio of the adhesion forces for different functional groups can be compared with values determined from the known surface energies. This concept was demonstrated by mapping the adhesive interaction of domains in a phase-separated lipid monolayer with the AF'M tip. The ratio of the adhesion forces for both phases corresponds with the theoretical number for the CHz and CH3 groups.