Microemulsion systems with water, toluene and nonionic surfactants are
interesting for application due to the excellent solvent properties of
aromatic hydrocarbons. In this study, the pseudo-binary phase diagram
(?fish-diagram?) of such a ternary system was investigated using a branched
technical alkyl polyethoxylate. Lutensol ON 50 (i-C10E5) was considered a
suitable surfactant. The system with technical branched i-C10E5 exhibits very
long and for compositions near optimum solubilization, i.e. the minimum
content of surfactant needed for a bicontinuous microemulsion, extremely long
times for equilibration. In addition to visual observation, qualitative
measurements of turbidity were performed with a UV-Vis spectrometer for
characterizing the behavior of this unusually sluggish system. Isothermal
phase diagrams at 20, 25 and 30?C yielded inconsistent results after the
change of temperature and the application of mechanical stress for different
treatment of the samples. Ternary mixtures of water, toluene, and Lutensol ON
50 seem to form long-living metastable states. The sluggishness and the
ambiguous phase behavior of the system are discussed. Inconsistent results
are attributed to the slow kinetics of the formation and destruction of
liquid crystals and the ability of the system to form miniemulsions within an
unusual concentration range.
Bicontinuous Microemulsion Type Cleansing Containing Silicone Oil. I. Comparison of Solubilization Behavior of Cyclic Siloxane with Polar Oil