Phase behavior of mixtures of polyoxyethylene(10) stearyl ether (Brij-76), 1-butanol, isooctane, and mixed polar solvents

Phase behavior of the mixtures of poly(oxyethylene) (10) stearyl ether (Brij-76), 1-butanol, isooctane, and mixed polar solvents

“…2). Typical fish-tail phase behavior appeared wherein the head of the fish (three-phase system) was skewed upward, similarly to other four-component systems reported earlier [44,45,52,[55][56][57][58]. O/w microemulsion coexisted with excess oil phase (Winsor I system, denoted as 2) at lower W 1 , whereas w/o type microemulsion coexisted with excess aqueous phase (Winsor II system, denoted as 2) at higher W 1 .…”

“…Bu and water are only partially soluble in each other. However, incorporation of surfactant can induce the mutual solubility of the ternary system [44,53]. In the present study, a large miscibility region was obtained in the ternary system Brij-76/Bu/water.…”

“…The effect is more pronounced for the TEG system than for that of EG. Earlier we reported that mixing of FA or DMF with water for the same quaternary system steadily decreased the solubilization capacity (both X b and W 1b ), with DMF having a more pronounced effect than FA [44]. The addition of FA or DMF induced a solvophobic effect, which in turn reduced the hydrophobic effect of the surfactant (an effect that induces micellization (aggregation) of surfactants), made the system less hydrophobic, and in turn increased the amount of cosurfactant required for the formation of HLB.…”

“…The convention followed herein (as reported in our previous works [44,53] For constructing temperature induced phase diagrams, α and W 1 were kept constant and X was plotted against T . When a mixture of water and EG (or TEG) was used with different weight fractions, ψ [= EG/(water + EG)], the mixed solvent was considered as a pseudo-one-component system [42].…”

“…All these aspects have prompted us to continue the series of studies of phase behavior and solubilization capacity of quaternary mixtures with mixed polar solvents using EG and TEG as the NPS. In Part I of this series [44], we reported the phase behavior of the quaternary mixture poly(oxyethylene) (10) stearyl ether (Brij-76)/1-butanol (Bu)/isooctane (i-Oc)/water in the presence of the organic polar solvents formamide (FA) and dimethyl formamide (DMF). It was found that mixing of FA or DMF with water reduced the solubilization capacity of the quaternary mixture, and the effect was more pronounced for DMF than for FA.…”