Field Gradient NMR for Polymer Systems with Cavities

Pulse field gradient (PFG) NMR method has become a useful technique for studying self-diffusion of probe molecules in polymer systems. Recently, high fieldgradient NMR system with a maximum strength of more than 1,000 G/cm and new pulse sequences are possible to measure the diffusion coefficient (D) with the order of l–10^-11 cm²/s in polymer systems. It is expected that the use of this system leads to sophisticated knowledge on nature of polymer systems as well as diffusional behavior of probe molecules in polymer systems. A number of papers, reviews, and monographs in this field have appeared [1–7]. In this section, some of most recent topics especially characterization of the polymer systems such as polymer gels and polymer media with controlled cavity through the diffusion experiments rather than principle of PFG NMR system and diffusional behavior of polymer chains have been described.