6. Conclusion

This article presents general concepts and applications for the determination of diffusion coefficients measured by field gradient NMR experiments in materials, colloids and soft matter. These experiments can be used to characterize molecular assemblies in solution, polymers in melt or solution and fluids confined in porous materials, and are particularly informative at nanometric scales.

The principle behind these measurements is to determine the mean square displacement of the molecules studied by NMR as a function of the diffusion time imposed by the measurement sequence. Modeling these data can provide the self-diffusion coefficient of molecules in a fluid, the hydrodynamic radius or mass of a molecular assembly, a macromolecule, an aggregate, a colloidal object or a micelle, or topological information on the geometry of a porous material. These measurements...