Transition interfacial film-bulk liquid

Figure 13. Depiction of the interfacial film-bulk liquid transition...

Many reports are available where the cationic surfactant CTAB has been used to prepare gold nanoparticles [127-129]. Giustini et al. [130] have characterized the quaternary w/o micro emulsion of CTAB/n-pentanol/ n-hexane/water. Some salient features of CTAB/co-surfactant/alkane/water system are (1) formation of nearly spherical droplets in the L2 region (a liquid isotropic phase formed by disconnected aqueous domains dispersed in a continuous organic bulk) stabilized by a surfactant/co-surfactant interfacial film. (2) With an increase in water content, L2 is followed up to the water solubilization failure, without any transition to bicontinuous structure, and (3) at low Wo, the droplet radius is smaller than R° (spontaneous radius of curvature of the interfacial film) but when the droplet radius tends to become larger than R° (i.e., increasing Wo), the microemulsion phase separates into a Winsor II system. 

We now take into account both the finite thickness of a liquid interlayer between droplets or bubbles and the variation in thickness in the transition zone between the interlayer and the equilibrium bulk liquid phase. It was already mentioned that there is a problem in using the approach of thickness-dependent interfacial tension if we try to use the Navier-Stokes equation for description of flow or equilibrium in thin liquid films, a thickness-dependent surface tension results in an unbalanced tangential stress on the surface of thin films. This is the reason why this particular approach is not used in this book. 

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