Spin-diffusion NMR

Asakura, T., Ashida, J., Yamane, T., Kameda, T., Nakazawa, Y., Ohgo, K., and Komatsu, K. (2001). A repeated beta-turn structure in poly(Ala-Gly) as a model for silk I of Bombyx mod silk fibroin studied with two-dimensional spin-diffusion NMR under off magic angle spinning and rotational echo double resonance. / Mol. Biol. 306, 291-305. 

Buffy, J. J., Waring, A. J. and Hong, M. (2005) Determination of peptide oligomerization in lipid bilayers using F-19 spin diffusion NMR. Journal of the American Chemical Society, 127(12), 4477 1483. 

In spin-diffusion studies it is possible to detect not only two but three domain sizes. The third domain can be considered the interface (i) between the other two domains, which can be different chemical species in a polymer blend or rigid crystalline (r) and mobile amorphous (m) material in a semicrystalline polymer. To illustrate this point, a mobility timescale is depicted in Fig. 7.2.25(a) and the simplified ID domain structure of PE underneath in (b). Rigid crystalline and mobile amorphous materials exhibit motion of chain segments with different correlation times Tc. The chains at the interface between both domains exhibit intermediate mobility. The exact ranges of correlation times in the individual domains depend on the particular choice of filters. Therefore, the values of domain sizes derived through spin-diffusion NMR also depend on the type of filters used. In particular, the interface is defined solely by the NMR experiment and can only be detected if the filters are properly chosen. 

Two possible scenarios can be envisaged for the structure of the hybrid material (see Fig. 11). The poly(ethylene oxide) block, albeit strongly interacting and partially penetrating, forms a pure PEO layer at the interface to the hydrophobic poly(isoprene) (Fig. 11, left-hand sketch) ( three-phase system). The other possibility is the complete dissolution of the PEO chains in the aluminosilicate, which results in the two-phase system depicted in the right-hand sketch of Fig. 11. Spin-diffusion NMR experiments showed that there appears to be no dynamic heterogeneity in the poly(ethylene oxide) chains, as would be expected for a three-phase system, giving rise to the conclusion that the hydrophilic... 

Information on the short distance spatial proximity of different segments of molecules can be obtained using the proton spin-diffusion NMR. This is a particularly valuable method for the... 

Finally, structural studies of two well-known silk fibroin proteins, Bombyx mori and Sarnia cynthia ricini, have been reported. Solid state NMR methods, such as C 2D spin-diffusion NMR and REDOR were used in addition to the quantitative use of the conformation-dependent chemical shifts, measured by C CP MAS. 

HEMA MA-PIB-MA Eree radical MAS, DSC, SAXS, H-f spin diffusion NMR 73... 

Domain Size Determination of Poly(phthalamide)/Poly(dimethylsiloxane) Block Copolymers by Solid-State Spin Diffusion NMR Spectroscopy... 

Summary H solid-state spin diffusion NMR spectroscopy was applied to calculate domain sizes of separated phases in poly(phthalamide)/poly(dimethylsiloxane) block copolymers. To initiate spin diffusion, the dipolar filter technique was used. The correlation between longer PDMS chains in the copolymer and bigger domains of the PDMS phase could be shown. 

The H spin diffusion NMR experiments were performed on a 300 MHz Bruker DSX spectrometer. 

Spin-diffusion NMR techniques, typically involving abundant homonuclei like H and F, are an important and powerful avenue for interrogating heterogeneous systems. Excellent reviews of this area have recently been published [55,56]. While the general use of spin-diffusimi to probe length scales of mixing in polymer blends, or to... 

Information on short-distance spatial proximity between different segments of molecules can be obtained using the proton spin-diffusion NMR method. This is a particularly valuable method for the characterization of polymer blends. For example, in case of PS/PVME cast films, the method provided information on blend composition, fraction of interacting groups (phenyl from PS with ether from... 

Figure 20 spin diffusion NMR curves of P3HT PCBM thin films spun-cast using the stated processing recipes. The curves shown were fit using the lamellar model. Copyright 2012 Wiley. Used with permission from Ref. [55]. 

K. Schaler, M. Roos, P. Micke, Y. Golitsyn, A. Seidlitz, T. Thum-Albrecht, H. Schneider, G. Hempel, K. Saalwachter, Basic principles of static proton low-resolution spin diffusion NMR in nanophase-separated materials with mobility contrast, Solid State Nucl. Magn. Reson. 72 (2015) 50—63. 

R.C. Nieuwendaal, C.R. Snyder, R.J. Kline, E.K. Lin, D.L. VanderHart, D.M. DeLongchamp, Measuring the extent of phase separation in poly-3-hexylthiophene/phenyl-C-61-butyric acid methyl ester photovoltaic blends with H-1 spin diffusion NMR spectroscopy, Chem. Mater. 22 (2010) 2930-2936. 

The 2D spin diffusion NMR experiment allows us to examine further the spectral assigments obtained from the ID and the 2D J-resolved experiments [51]. It also provides new details concerning distribution of hydrocarbons in zeolite ZSM-5. Spectral spin diffusion in the solid state involves simultaneous flip-flop transitions of dipolar-... 

Nieuwendaal et al. showed that because of spin diffusion, NMR sensitivity to intermolecular correlations at the nanometer length scale, and its unambiguous chemical contrast, can be used to measure the phase behavior and domain sizes of BHJs of the P3HT/PCBM system [52]. When increasing the efficiency of OPVs, thermal treatment is generally thought of as a vital step in fabrication process however, the formation of needle-like PCBM crystallites which normally cause a lower effidency is one unfortunate consequence of thermal treatment. 

Caravatti, P., Neuenschwander, P., and Ernst, R. (1986) Characterization of polymer blends by selective proton spin-diffusion NMR measurements. Macromolecules, 19 (7), 1889-1895. 

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