Applications of high resolution solid state nuclear magnetic resonance spectroscopy to surface studies

Abstract

Surface properties have important effects on materials such as polymer composites, and technologies such as catalysis. The influences of surface properties arise on both macroscopic and microscopic scales. Therefore there is a need to characterize surfaces on a molecular level. A range of spectroscopic techniques are utilized for surface characterization. Recently, high resolution solid state nuclear magnetic resonance (NMR) Spectroscopy has proven to be a significant analytical technique for surface analysis. Solid state NMR is a particularly advantageous method for surface studies because there is no sample preparation necessary which could alter the molecular structure of the material as in other spectroscopic analyses. This technique allows for the detection of subtle molecular changes in the systems under study both qualitatively and quantitatively. With the range of information that can be obtained. Including: chemical structure, interactions, and molecular motion, solid state NMR promises to be a powerful addition to the established methods for the study of surfaces. This review focuses on surface characterization using the techniques developed for solid state magic-angle NMR where the observe nucleus is chosen to suit the surface system. The NMR studies of surfaces carried out to date can be divided primarily into 2 areas: the characterization of chemically modified silica surfaces and the study of the nature of molecular adsorption on catalytic surfaces. The solid state NMR studies of these systems have demonstrated that high resolution spectra are attainable and that this method of characterization, with its capabilities and relative ease of interpretation, is a valid and useful one.