From Helical Jump to Chain Diffusion: Solid-State NMR Study of Chain Dynamics in Semi-Crystalline Polymers

Recent progresses in solid-state NMR study of the helical jump and chain diffusion in semi-crystalline polymers are briefly surveyed. Special emphasis is placed on the nature of helical jump, chain diffusion and their correlation. Combination of the new solid-state NMR techniques allows dynamic elucidation with different length scales from atomistic to nanoscopic and the correlation between them. The morphological factors influencing the dynamics such as the thickness of crystal lamellae, the chain entanglements in the amorphous phase, the interphase between crystalline and amorphous regions of polymer sample are discussed. The correlation between the helical jumps and the chain diffusion is realised by their different temperature dependence and is further discussed in terms of the defect transfer mechanism.