Chemical force microscopy: probing chemical origin of interfacial forces and adhesion

Abstract

Intermolecular interactions between distinct chemical functionalities define a multitude of adhesion events in chemistry, biology and materials science. Modern techniques for measuring molecular level forces have allowed direct quantitative characterization of these interactions. In particular, chemical force microscopy (CFM), which uses the probe tip of a force microscope covalently modified with specific organic functional groups, provides a flexible approach for studying interactions between specific chemical functionalities. In this review, we survey the progress in CFM in recent years as it applies to adhesion of soft materials. We show how new developments in the experimental and theoretical approaches continue to build a realistic and detailed picture of adhesion interaction in condensed phases. We specifically highlight the importance of the kinetics of the unbinding processes and solvation effects in determining the strength of intermolecular interactions. We also describe some recent new directions in CFM, such as high-throughput adhesion measurements and mapping of full intermolecular potentials.