SOLUBILIZATION OF 2-PHENYLETHANOL IN SURFACTANT VESICLES AND MICELLES

The solubilization of 2-phenylethanol (PEA) was measured over a wide range of solute activities using didodecyldimethylammonium bromide (DDAB) vesicles and dodecyltrimethylammonium bromide (DTAB) micelles. The solubilization equilibrium constant was found to be greater for DDAB vesicles than for DTAB micelles. At small values of X(p) (the mole fraction of the solubilizate in an aggregate), the activity coefficient of PEA solubilized in the DDAB vesicle was much less than 1, and the value increased with increasing X(p). Further, the vesicular diameter increased with X(p) and remained approximately constant from X(p) = 0.3 to X(p) = 0.5. It was found that PEA is solubilized more strongly in DDAB vesicles than in DTAB micelles, and that it penetrates into the hydrophilic region of the vesicles as well as the micelles.