Abstract
The results of NMR, and especially pulsed field gradient NMR (PFG NMR) investigations, are summarized. Pulsed field gradient NMR technique makes it possible to investigate directly the partial self-diffusion processes in spatial scales from tenth micron to millimeters. Modern NMR spectrometer diffusive units enable to measure self-diffusion coefficients from 10−13 m2/s to 10−8 m2/s in different materials on 1 H, 2 H, 7 Li, 13 C, 19 F, 23 Na, 31 P, 133 Cs nuclei. PFG NMR became the method of choice for reveals of transport mechanism in polymeric electrolytes for lithium batteries and fuel cells. Second wide field of application this technique is the exchange processes and lateral diffusion in biological cells as well as molecular association of proteins. In this case a permeability, cell size, and associate lifetime could be estimated. The authors have presented the review of their research carried out in Karpov Institute of Physical Chemistry, Moscow, Russia; Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia; Kazan Federal University, Kazan, Russia; Korea University, Seoul, South Korea; Yokohama National University, Yokohama, Japan. The results of water molecule and Li+, Na+, Cs+ cation self-diffusion in Nafion membranes and membranes based on sulfonated polystyrene, water (and water soluble) fullerene derivative permeability in RBC, casein molecule association have being discussed.
Highlights
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We have reviewed the water molecule and alkali metal ion diffusion data, which are compared with ionic conductivity results [16,17,21,25,55,56,57,58,59,60,61,105]
The principal part of these systems is formed by a polymer ion exchange membrane that should have high ionic conductivity
Summary
Acid ionic form The most thoroughly studied membranes are perfluorinated sulfonate cation-exchange membranes Nafion, MF-4SC [18,19,20,21,22,23,25], MF-4SC membranes modified with inorganic dopants [21] and perfluorinated carboxylic membranes F-4CF in various ionic forms [20,21]. The main spin relaxation mechanism of 23Na and 133Cs nuclei is quadrupole moment–gradient ligand electric field interaction We have observed these nuclei diffusion decays in aqueous solution and in sulfocation-exchange membranes (MSC) based on polyethylene sulfonated grafted polystyrene [16,17], which maximum water content λ is more compared to Nafion membrane. At this condition cation water molecule shell is high-symmetric. SO3− group directly and a contact ionic pair is forming This is the reason of low mobility and high self-diffusion activation energy of cesium cation in Nafion.
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