Phase behavior and formation of reverse cubic phase based emulsion in water/poly(oxyethylene) poly(dimethylsiloxane) surfactants/silicone oil systems

Citation
Mh. Uddin et al., Phase behavior and formation of reverse cubic phase based emulsion in water/poly(oxyethylene) poly(dimethylsiloxane) surfactants/silicone oil systems, LANGMUIR, 17(17), 2001, pp. 5169-5175
Citations number
30
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
LANGMUIR
ISSN journal
0743-7463 → ACNP
Volume
17
Issue
17
Year of publication
2001
Pages
5169 - 5175
Database
ISI
SICI code
0743-7463(20010821)17:17<5169:PBAFOR>2.0.ZU;2-Q
Abstract
The phase behavior of long hydrophobic A-B type silicone surfactants, Me3Si O-(Me2SiO)(m-2)-Me-2-SiCH2CH2CH2-O-(CH2CH2O)(n)H (SimC3EOn), in water and w ater + octamethylcyclotetrasiloxane (D-4) was investigated by studying phas e behavior and small-angle X-ray scattering. Si25C3EO15.8 forms a reverse m icellar cubic phase (I-2) in water and water + D-4 systems. This cubic phas e is highly thermally stable in a surfactant-water binary system. The therm al stability decreases monotonically with addition of silicone oil. Althoug h the solubilization of water in the reverse cubic phase is low, a very lar ge 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. D-4 molecules penetrate into the surfactant palis ade layer in the reverse micelles forming the I-2 phase and expand the effe ctive cross-sectional area per surfactant, as (penetration). The continuous penetration of oil destabilizes the I-2 phase structure, and therefore the melting temperature of the phase decreases. The incorporation of D-4 into the I-2 phase in the aqueous mixtures of Si14C3EO7.8, Si25C3EO7.8, Si25C3EO 12.2, and Si25C3EO15.8 varies with both the hydrophilic and lipophilic chai n lengths of silicone surfactants.