NMR self-diffusion studies

The first part of this review deals with the synthesis and characterization of dendritic aliphatic polyesters based on 2,2-bis(dimethylol)propionic acid (bis-MPA) and 1,1,1 -tris(hydroxyphenyl)ethane (THPE), as core molecule. The convergent growth approach described earlier was applied. We also present H NMR self-diffusion studies of dendrimers of first, second, and third generation. 

Soderman et al. [8] gave an overview of NMR self diffusion studies of emulsion systems. They stated that a log-normal distribution function gives a better fit than a normal distribution. Several examples are given including margarine and hydrocarbon gel emulsions. 

According to Eqs. (4)-(6), the molecular mean square displacements and thus the self-diffusion coefficients may be determined from the slope of a semilogarithmic plot of the PFG NMR signal F versus (Sg) The observation time of self-diffusion is the separation between the two field gradient pulses, t. Owing to their relatively large gyromagnetic ratio and to their natural abundance of 1, protons provide very suitable conditions for NMR self-diffusion studies, but C 44), F 45), and Xe 46-48) resonances have also been used successfully in recent PFG NMR studies of zeolites. 

C. Analysis of Molecular Translations and Rotations by Combined H NMR Relaxation and NMR Self-Diffusion Studies... 

B. Combined H NMR Relaxation and Pulsed-Field Gradient NMR Self-diffusion Studies for Propane in ZSM-5 AND NaX... 

Garasanin, T, Cosgrove, T, Marteaux, L., and Zick, K. NMR self-diffusion studies on PDMS oil-in-water emulsions, Langmuir, 18, 10298, 2002. 

Nilsson, P.G. and Lindman, B. (1982) Solution structure of nonionic surfactant microemulsions from NMR self-diffusion studies. /. Phys. Chem., 86, 271-279. 

Das, K.R Ceglie, A., Lindman, B. and Friberg, S. (1987) Fourier-transform NMR self-diffusion studies of a nonaqueous microemulsion system. /. Colloid Interface Sci. 116, 390 400. 

Table 2 Results of the PPG NMR self-diffusion studies with CF4 adsorbed in AIPO4-5 at 180 K, represented in terms of the single-file mobility factor F [cf. Eq. 3] and the singleparticle diffusivityD [cf. Eq. 8]. The mean free distance I is calculated according to Eq. 10. The errors of the experimental values are about 50% [47]...

The present review focuses on the study of microemulsion structure by NMR, since this is the main aspect about which NMR is capable of providing unique information. We mainly discuss NMR self-diffusion studies, as they have been the most informative and, in particular, self-diffusion work together with microscopy is probably the only direct... 

Ihre, H., Hult, A., and Soderlind, E. (1996) Synthesis, characterization, and H-1 NMR self-diffusion studies of dendritic aliphatic polyesters based on 2,2-bis(hydroxymethyl)propionic acid and l,l,l-tris(hydroxyphenyl)ethane. J. Am. Chem. Soc., 118, 6388-6395. 

Self-diffusion measurements using the NMR technique have also elucidated the matter of water structure in the pool up to 10-15 water molecules per — 03 group (when AOT is the surfactant) were shown to be structurally perturbed [42]. From self-diffusion NMR studies of AOT-induced w/o microemulsions, Maitra proposed several regions of bound water in the water pool domain [43]. The state of water in the pool for cationic surfactant-containing microemulsions (water/dodecyidimethyl ammonium bromide or didodecyldimethyl ammonium bromide/chloroform or cyclohexane) was examined by NMR self-diffusion studies at different [Fl20]/[amphiphile] ratios or rvalues. Three types of water molecules— bound, aggregated, and free—in various proportions have been envisaged [44]. 

Shapiro, Y. (1999) H-1 NMR self-diffusion study of morphology and structure of polyvinyl alcohol cryogels, J. Colloid Interface Sci., 212, 453-65. 

Olsson, U., Shinoda, K., and Lindman, B. 1986 Change of the structure of microemulsions with the hydrophile-lipophile balance of nonionic surfactant as revealed by NMR self-diffusion studies, J. Phys. Chem. 90 4083-4088. 

Stubenrauch, C. and Findenegg, G.H. 1998 Microemulsions supported by octyl monoglucoside and geraniol. 2. An NMR self-diffusion study of the microstructure,... 

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