Ternary systems self-diffusion coefficients

Figure C2.3.8. Self-diffusion coefficients at 45°C for AOT ( ), water ( ) and decane ( ) in ternary AOT, brine (0.6% aqueous NaCl) and decane microemulsion system as a function of composition, a. This compositional parameter, a, is tire weight fraction of decane relative to decane and brine. Reproduced by pennission from figure 3 of [46].

Zielinski and Hanley [AlChE J. 45,1 (1999)] developed a model to predict multicomponent diffusivities from self-diffusion coefficients and thermodynamic information. Their model was tested by estimated experimental diffusivity values for ternary systems, predicting drying behavior of ternary systems, and reconciling ternary selfdiffusion data measured by pulsed-field gradient NMR. 

If Dp depends significantly on Cp, extrapolation to Cp 0 must be performed. The initial slope of the dependence of Dp on probe concentration, and the slope s dependence on matrix concentration, have been measured in some systems and should be accessible to theoretical analysis. In this review If the probe and matrix polymers differ appreciably in molecular weight or chemical nature, the phrase probe diffusion coefficient is applied. If the probe and matrix polymers differ primarily in that the probes are labelled, the phrase self diffusion coefficient is applied. The tracer diffusion coefficient is a single-particle diffusion coefficient, including both the self cind probe diffusion coefficients as special cases. The interdiffusion and cooperative diffusion coefficients characterize the relaxation times in a ternary system in which neither m lcrocomponent is dilute. 

In Chapter 1, Murgia, Palazzo, and coworkers investigated the physicochemical behaviors of a binary IL bmimBF and water, and the ternary NaAOT, water and bmimBF mixtures essentially through the evaluation of the self-diffusion coefficients of the various chemical species in solution by PGSTE-NMR experiments. The diffusion of water molecules and bmimBF ions were found to be within different domains, which suggested that the systems were nanostructured with formation of micelles having positive curvature and a bicontinuous micellar solution for the former and the later systems, respectively. The remarkable differences between the two systems are attributed to the specific counterion effect between the aforementioned ILs and the anionic surfactant. In Chapter 2, Bermudez and coworkers focused on the characterization of small (conventional surfactants) and polymeric amphiphiles (block copolymers) in different types of ILs (imidazolium, ammonium. 

Here, the apparent self-diffusion coefficient D pp of the alcohol in the ternary system can be measured by the NMR spin-echo technique [6]. is the selfdiffusion coefficient of the alcohol within or associated with the micelles and the corresponding value in the aqueous pseudophase it is approximated by measuring the self-diffusion coefficient in the binary D20-pentanol system. As is much smaller than the partition coefficient p can be approximated by... 

Figure 20.2 Influence of the hydrocarbon chain length m on the micellar self-diffusion coefficient D in ternary Ci4DMAO/CmH2ni+2/D20 surfactant systems. For m = 6, cyclohexane C6H12 has been chosen as the solute.

Figure 16 Variation of the water self-diflfusion coefficient with the water + surfactant volume fraction <1> for three different dilution lines corresponding to different water/surfactant ratios in the ternary DDAB-water-dodecane system. Above a certain concentration, which depends on the water/surfactant ratio, the water diffusion coefficient increases dramatically, indicating a water droplet-to-bicontinuous transition. (Data from Ref. 48.)...

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