Weak Micelle-Like Aggregation in Ternary Liquid Mixtures as Revealed by Conductivity, Surface Tension, and Light Scattering

Abstract

A very small concentration of NaBr is added to ternary, transparent, and thermodynamically stable mixtures of water, ethanol, and octanol. Measuring the electrical conductivity along lines with constant water to ethanol ratios reveals remarkable composition dependencies similar to those found in classical surfactant-based microemulsions. Indeed, light-scattering experiments along the same composition lines and additional surface tension measurements confirm the onset of aggregation and possibly direct, bicontinuous, and reversed structures in these surfactant-free systems such as in classical microemulsions.

The Nanostructure Studies of Surfactant-Free-Microemulsions in Fragrance Tinctures

“…However, due to the lack of the surfactant, conductivity enhances only within one order of magnitude. The molecule forming the interface between water droplets and the citronellol-rich surrounding medium has been found in previous studies 2,9 unequivocally as being ethanol, and according to that in the systems studied here, the ethanol is the main component of the interfacial film whenever microstructures are present. As shown in Figure 3a, the low conductivity below φ w p suggests that the reverse droplets are discrete (isolated droplets in a non-conducting citronellol medium, forming w/o microemulsion) and show rare interaction.…”

“…Moreover, changes of slopes are also found when evaporation rates are plotted versus the amount of oil phase during the transition from o/w to w/o domains, a phenomenon that is widely used in formulation of long-lasting perfume formulation. 2 According available literature only few recent studies reported the theoretical analysis based on the percolation phenomenon, which occurs as the microstructure of microemulsions changes. [3][4][5][6] Recently, the static and dynamic percolation models have been proposed for describing the mechanism of percolation.…”

Theory of nonionic hydrophobic solutes in mixture solvent: Solvent-mediated interaction and solute-induced phase separation

“…as thermal fluctuations [8][9][10][11]14 . For water(1)-ethanol(2)octanol (3), results of molecular dynamics simulation 8,11 lead to rough estimatations, n(G 0 13 − G 0 23 ) = 100 − 300, −g 3 = 20 − 60, and g 2 3 nχ = 300 − 3000, at X = 0.2.…”

“…In water-alcohol solvents, nanometer-sized solute-rich aggregates preexist with alcohol molecules covering them in one-phase states [8][9][10][11]13 . Then, they should play the role of embryos of critical liquid droplets consisting of solute and alcohol molecules.…”

Nanostructures in clear and homogeneous mixtures of rapeseed oil and ethanol in the presence of green additives

“…Thus, we can observe a bell-shaped conductivity curve with a maximum for a concentration in ethanol of about 60 % in weight fraction. If we refer to other works relative to conductivity measurements in the pre-ouzo region [32], we really have to consider the presence of two pseudo-phases to explain such behavior.…”