Viscous isotropic phase composition

In hydrophobe-dominated compositions, such as aerosol OT-water systems, inverted middle and inverted viscous isotropic phases can occur in which the tails point outward towards the hydrophobic medium while water is trapped inside. ... 

Between and Tq at relatively high surfactant concentration are the neat and middle phase liquid crystalline regions. In addition. X-ray diffraction studies [16] have revealed several other phases intermediate in composition between the neat and middle phases, including the viscous isotropic phase. A comprehensive account of the structure of these and other mesomorphous phases is given by Skoulios [18]. 

The presence of mixed surfactant adsorption seems to be a factor in obtaining films with very viscous surfaces [411]. For example, in some cases the addition of a small amount of non-ionic surfactant to a solution of anionic surfactant can enhance foam stability due to the formation of a viscous surface layer, which is possibly a liquid crystalline surface phase in equilibrium with a bulk isotropic solution phase [25,110], In general, some very stable foams can be formed from systems in which a liquid crystal phase is present at lamella surfaces and in equilibrium with an isotropic interior liquid. If only the liquid crystal phase is present, stable foams are not produced. In this connection foam phase diagrams may be used to delineate compositions that will produce stable foams [25,110],... 

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