SOLID-STATE NMR OF HETEROGENEOUS MATERIALS

Most solid materials are heterogeneous on a microscopic or a macroscopic scale, or both. Examples of heterogeneities are the phase structure of incompatible polymers, pores in ceramics, distributions in mechanical stress, variations in molecular order and mobility of extruded polymers, and chemical composition in composite materials. Nuclear magnetic resonance (NMR) spectroscopy has unique capabilities for detailed characterization of such heterogeneities: Microscopic structures between 1 nm and 200 nm can be investigated in spin-diffusion studies, whereas macroscopic structures above 10-mu-m can be analyzed in imaging experiments.