Phase Behavior and Formation of Reverse Cubic Phase Based Emulsion in Water/Poly(oxyethylene) Poly(dimethylsiloxane) Surfactants/Silicone Oil Systems

Abstract

The phase behavior of long hydrophobic A−B type silicone surfactants, Me3SiO−(Me2SiO) m - 2−Me2SiCH2CH2CH2−O−(CH2CH2O) n H (Si m C3EO n ), in water and water + octamethylcyclotetrasiloxane (D4) was investigated by studying phase behavior and small-angle X-ray scattering. Si25C3EO15.8 forms a reverse micellar cubic phase (I2) in water and water + D4 systems. This cubic phase is highly thermally stable in a surfactant−water binary system. The thermal stability decreases monotonically with addition of silicone oil. Although the solubilization of water in the reverse cubic phase is low, a very large amount of excess water can be incorporated in a so-called reverse cubic phase based concentrated emulsion. The emulsion stability is enhanced upon addition of silicone oil. D4 molecules penetrate into the surfactant palisade layer in the reverse micelles forming the I2 phase and expand the effective cross-sectional area per surfactant, a S (penetration). The continuous penetration of oil destabilizes the I2 phase structure, and therefore the melting temperature of the phase decreases. The incorporation of D4 into the I2 phase in the aqueous mixtures of Si14C3EO7.8, Si25C3EO7.8, Si25C3EO12.2, and Si25C3EO15.8 varies with both the hydrophilic and lipophilic chain lengths of silicone surfactants.

Performance of a biosurfactant produced by Bacillus subtilis LAMI005 on the formation of oil / biosurfactant / water emulsion: study of the phase behaviour of emulsified systems

“…For NH140 oil + biosurfactant + water the temperature transition is reached at T = 80 °C, for surfactin concentration below 0.3 (above 0.4 the transition temperature decreases to 75 °C). This was also observed by Uddin et al (2001) in a phase diagram for a water-in-surfactant binary system (Si 25 C 3 EO 15,8 ).…”

Phase Behavior and Rheological Analysis of Reverse Liquid Crystals and W/I2 and W/H2 Gel Emulsions Using an Amphiphilic Block Copolymer

“…The emulsions formed, in both cases, were white, due to the difference between the internal and external phase refractive index, 6,16 highly viscous, stiff, and presented shear-thinning behavior and a yield stress depicts (Figure 1), and considering the components used, the structure of the liquid crystal is assumed to be reverse. Diluting the samples in cyclohexane, and not being able to dilute them in water, confirmed that the internal phase was indeed water.…”

Structure of Diglycerol Polyisostearate Nonionic Surfactant Micelles in Nonpolar Oil Hexadecane: A SAXS Study

“…Due to an unfavorable direct contact between the hydrophilic part and oils, reverse micelles are usually formed when an amphiphile is added into nonpolar solvents. Reverse micelles are mostly observed in the ternary mixtures of surfactant/water/oil, mostly in oil rich regions [11][12][13] . Furthermore, they have also been observed in aqueous systems of lipophilic surfactant in surfactant rich regions 14,15 .…”