Probe microscopy of organics, an update

Scanning probe microscopy as applied to organic materials has evolved from the original demonstrations that the technique could successfully and non-invasively image these soft samples [1]. One evolutionary pathway has been to switch from qualitative to more quantitative measurements. Among those studies are measurements of adhesion [2-5], elasticity [6], friction [7], and quantification of individual bonding interactions [8-11]. The use of this technique to derive absolute values for these properties is still limited by uncertainties such as the degree to which the instrument itself contributes to the measured signals, an exact knowledge of the geometry of the interface between sample and probe, and which intermolecular interactions are contributing to measured signals. In this overview, we will address these issues, with particular attention to the ''two-body'' (or ''many-body'') nature of the tip-sample interaction. These multi-body interactions will be discussed in the contexts of adhesion, delamination, friction, and bio-specificity.