Formation of Cubic-Phase Microemulsions with Anionic and Cationic Surfactants at Equal Amounts of Oil and Water

✍ Scribed by Xingfu Li; Hironobu Kunieda

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 154 KB
• Volume: 231
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.2000.7128

✦ Synopsis

The formation and microstructure of cubic phases were investigated in anionic and cationic surfactant-containing systems at 25 • C. In the system sodium dodecyl sulfate(SDS)-dodecyltrimethylammonium bromide(DTAB)-water, mixing of two surfactants shows the phase transition hexagonal phase (H 1 ) → surfactant precipitate, accompanied by an obvious decrease in the crosssectional area per surfactant in the rod micelles of the hexagonal liquid crystal. In the mixed systems brine(A)-dodecane(B)-SDS(C)-DTAB(D)-hexanol(E), the isotropic discontinuous cubic phase is formed from the H 1 phase at a low cationic surfactant weight fraction, Y = D/(C + D), and from the lamellar phase at high Y upon dilution with equal amounts of oil and brine, respectively. The minimum surfactant concentration to form the cubic phase decreases with increases both in cationic surfactant weight fraction Y from 0 to 0.30 and in hexanol weight fraction, W 1 = E/(C + D + E), accordingly. The maximum solubilization for oil of the cubic phase reaches 43 wt% at 14 wt% of mixed surfactants and alcohol.