Signatures of normal and anomalous diffusion in nanotube systems by NMR

Abstract This paper reviews results of our recent studies of diffusion of gaseous sorbates in nanotube systems. 13 C pulsed field gradient (PFG) NMR at 17.6 T was used to probe diffusion of tetrafluoromethane in aluminosilicate nanotubes at several sorbate loadings. The results of PFG NMR measurements were compared with the corresponding data obtained by molecular dynamics simulations. The diffusion in this system was found to follow the laws of normal (i.e. Fickian) transport. At the same time, experimental data pointing at single-file diffusion were recorded for xenon gas confined inside dipeptide l -alanyl l -valine (AV) nanotubes. These data were obtained by means of high field 129 Xe PFG NMR. The PFG NMR data are compared with recently reported hyperpolarized tracer exchange 129 Xe NMR in the same material.