Atomic force microscopy at submolecular and single chemical group resolution

Abstract

In this paper, we introduce frequency modulation atomic force microscopy (FM-AFM) for visualizing atomic-scale surface structures in liquid. Recent achievements in FM-AFM development allow us to visualize intramolecular structures for organic molecules and biomolecular assemblies formed by weak intermolecular interactions at a single functional group level. In contrast, visualization of fluctuating structures and vertically extended chemical structures is difficult, even with the FM-AFM technique. To overcome the technical limitation of the FM-AFM, three-dimensional scanning AFM (3D-AFM) is developed for visualizing the spatial distribution of solvation and fluctuation structures at the solid–liquid interface. The applications of 3D-AFM techniques are also introduced.