PNNL

Abstract

One of the challenging questions for a variety of research fields is visualizing solid-liquid interfaces and understanding how they are affected by solution conditions such as ion concentrations, pH, ligands, and trace additives as well as the underlying crystallography and chemistry. In this context, three-dimensional fast force mapping (3D FFM) has emerged as a promising tool for investigating solution structure at interfaces. This capability is based on atomic force microscopy (AFM) and allows the direct visualization of surfaces in three spatial dimensions with sub-nanometer resolution. Here we provide a detailed description of the experimental protocol for acquiring 3D FFM data. We discuss the main considerations for optimizing the operating parameters depending on the sample and application. Moreover, the basic methods for data processing and analysis are discussed, including the transformation of the measured instrument observables into tip-sample force maps that can be linked to local solution structure. Finally, we shed light on some of the outstanding questions related to 3D FFM data interpretation and how this technique can become a central tool in the repertoire of surface sciences.