The micellization process of binary surfactant mixtures containing cationic surfactants viz. dodecyl pyridinium halide (C12PyX; X=Cl, Br, I), tetradecyl pyridium bromide (C14PyBr), and hexadecyl pyridium halide (C16PyX; X=Cl, Br) and a nonionic surfactants viz. dodecyl nonapolyethylene glycol ether (C12 E9), dodecyl decapolyethylene glycol ether (C12 E10), dodecyl dodecapolyethylene glycol ether (C12 E12), and dodecyl pentadecapolyethylene glycol ether (C12E15) in water at different mole fractions (0-1) were studied by surface tension method. The composition of mixed micelles and the interaction parameter, β evaluated from the CMC data obtained by surface tension for different systems using Rubingh's theory were discussed. Activity coefficient (f1 and f2) of cationic surfactant (CnPyBr)/C12Em (n=12, 14, 16 and m=10, 12, 15) mixed surfactant systems were evaluated, which shows extent of ideality of individual surfactant in mixed system. The stability factors for mixed micelles were also discussed by Maeda's approach, which was justified on the basis of steric factor due to difference in head group of nonionic surfactant.
- Interaction parameter
- Mixed surfactant