Analytical Methods for Characterization of Nanomaterial Surfaces

This review discusses the present knowledge and recent advances in the techniques used to analyze nanomaterial surfaces, including traditional techniques that are easily accessible to researchers as well as advanced techniques and recent developments. Each technique will only be discussed in the context of its utility in nanomaterial surface characterization. We highlight both advantages and drawbacks of the techniques, and review examples from literature with the focus on recent publications. The following topics will be discussed: (1) ligand structure and conformation, (2) ligand density, (3) surface charge, (4) hydrophobicity, (5) ligand shell thickness, (6) binding affinity, and (7) surface morphology. This list is by no means complete, but rather serves as a discussion platform to draw attention to this important yet challenging field of nanomaterial surface characterization. Techniques that can provide quantitative information on the nanomaterial surfaces will be discussed whenever possible. As most nanomaterials are in the form of nanoparticles, both terms will be used interchangeably throughout the text.