Chemical Composition of Polymer Surfaces Imaged by Atomic Force Microscopy and Complementary Approaches

In this article we review the recent developments in the field of high resolution lateral mapping of the surface chemical composition of polymers by atomic force microscopy (AFM) and other complementary imaging techniques. The different AFM approaches toward nanometer scale mapping with chemical sensitivity based on chemical force microscopy (CFM) are discussed as a means to unravel, for instance, the lateral distribution of surface chemistry, the stability of various types of functional groups in various environments, or the interactions with controlled functional groups at the tip surface. The applicability and current limitations of CFM, which allows one to image chemical functional group distributions with a resolution in principle down to the 10–20 nm scale, are critically discussed. In addition, complementary imaging techniques are briefly reviewed and compared to the AFM-based techniques. The complementary approaches comprise various spectroscopies (infrared and Raman), secondary ion mass spectrometry (SIMS), matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), X-ray photoelectron spectroscopy (XPS or ESCA), and near-field optical techniques used for imaging.