Interfacial Force Microscopy: Selected Applications

The interfacial force microscope (IFM) was developed in the early 1990s out of a research program aimed at fundamental studies of interfacial adhesion. The desire was to evaluate the adhesive bond and its failure involving controlled interfacial surfaces. One of the most important aspects of this interfacial control involves morphological defects, which are most easily handled by utilizing a very small surface for at least one of the interfaces, for example, by using a small probe. The atomic force microscope (AFM) had recently burst onto the scene [1,2] and, thus, all the necessary control features were already in place. The idea then was to measure the interfacial force as a function of the relative separation of the two surfaces. The behavior of this force upon approach would give a “fingerprint” of the bonding (e.g., van der Waals, electrostatic, covalent, etc.) and the withdrawal would give information on the bond failure, providing a detailed measure of the interfacial bonding process.