Diffusion of the Dispersed Phase in a Highly Concentrated Emulsion: Emulsion Structure and Film Permeation
✍ Scribed by Balin Balinov; Per Linse; Olle Söderman
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 212 KB
- Volume
- 182
- Category
- Article
- ISSN
- 0021-9797
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✦ Synopsis
A highly concentrated emulsion, made up of lecithin, C 12 EO 4 , cerned with the latter type.
n-heptane, and brine (1 wt% NaCl solution), has been investigated
Although numerous studies have been concerned with the by means of the NMR PFG method. The emulsion is of the W/O structure of concentrated emulsions, very few studies, if any, type and contains 96 wt% brine. The self-diffusion of the water have dealt with the dynamic properties of these systems. The has been investigated at three different diffusion times, and it is purpose of this work has been to apply the NMR PFG found that the water diffusion is Gaussian over the range of the method to concentrated emulsions so as to obtain informarelevant experimental parameters covered, with a value for the tion pertaining both to the dynamic properties of the disself-diffusion coefficient that is reduced by a factor of roughly 10, persed phase and to the structural properties of concentrated as compared with the bulk water diffusion coefficient. The reduction is caused by the presence of a thin liquid film which separates emulsions.
the emulsion droplets and which exerts a diffusion barrier for the
In the field of surfactant science, the PFG method has been water molecules within the droplets. The data are interpreted by extensively applied to micellar and microemulsion systems, means of a simulation procedure, in which particles perform a where it is used to determine component-resolved self-diffurandom walk in droplets, the surface of which is partially permesion coefficients. One reason why the method is so powerful able to the particles. With independent structural information the in this context is the fact that the information the self-diffusimulation approach yields a permeability coefficient for the water sion coefficients convey about different features of the invescrossing the film. Finally, it is argued that concentrated emulsions tigated systems is easily extractable and one does not have are excellent model systems for developing PFG methods in studyto resort to complicated modeling as is the case with other ing the general class of porous systems.