Mixed micelles of cationic surfactants with bulky head groups in the presence of alkoxyethanols - A study on additive-solvent interactions of mixed micelles

Binary surfactant mixtures of tetradecyltriphenylphosphonium bromide (TTPB) and tetradecyltrimethylammonium bromide (TTAB) in the presence of ethylene glycol (EG), ethylene glycol monomethyl ether (EGMME), ethylene glycol mon oethyl ether (EGMEE), diethylene glycol (DEG), diethylene glycol monomethyl ether (DEGMME) and diethylene glycol monoethyl ether (DEGMEE) were measure d over the entire mole fraction range of TTAB (alpha (TTAB)). The binary mi xtures contained 10-30% w/w of each additive at 30 degreesC. Each conductiv ity curve shows a single break corresponding to the c.m.c. value in each ca se. From the conductivity data, various micellar parameters in the presence of alkoxyethanols were computed. The mixing behaviour of TTPB+TTAB is clos e to ideal; the behavior in pure water and in the presence of various alkox yethanols is quite similar. A variation in micellar parameters in the prese nce of alkoxyethanols showed that the induction of the additive primarily d isrupts the hydrogen-bonded aqueous structure, which is the main driving fo rce for mixed micelle formation.