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Microemulsion phase behavior of anionic‐cationic surfactant mixtures: Effect of tail branching
Author(s) -
Upadhyaya A.,
Acosta E. J.,
Scamehorn J. F.,
Sabatini D. A.
Publication year - 2006
Publication title -
journal of surfactants and detergents
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.349
H-Index - 48
eISSN - 1558-9293
pISSN - 1097-3958
DOI - 10.1007/s11743-006-0387-6
Subject(s) - pulmonary surfactant , cationic polymerization , microemulsion , chemistry , branching (polymer chemistry) , chromatography , inorganic chemistry , organic chemistry , biochemistry
This research evaluated middle‐phase microemulsion formation by varying the mole ratio of anionic and cationic surfactants in mixtures with four different oils (trichloroethylene, n ‐hexane, limonene, and n ‐hexadecane). Mixtures of a double‐tailed anionic surfactant (sodium dihexyl sulfosuccinate, SDHS) and an unbalanced‐tail (i.e., doubletailed with tails of different length) cationic surfactant (benzethonium chloride, BCl) were able to form microemulsions without alcohol addition. The amount of NaCl required to form the middle‐phase microemulsion decreased dramatically as an equimolar anionic‐cationic surfactant mixture was approached. Although the mixture of anionic and cationic surfactants demonstrated a higher critical microemulsion concentration (cμc) compared to the anionic surfactant alone, the Winsor Type IV single‐phase microemulsion started at lower surfactant concentrations for the anionic‐cationic mixture than for the anionic surfactant alone. Under optimum middlephase microemulsion conditions, mixed anionic‐cationic surfactant systems solubilized more oil than the anionic surfactant alone. Pretreatment detergency studies were conducted to test the capacity of these mixed surfactant systems to remove oil form fabrics. It was found that anionic‐rich mixed surfactant formulations yielded the largest oil removal, followed by cationic‐rich systems.