Solubilization of polycyclic aromatic hydrocarbons in f127 and p123 aqueous micellar solutions

The solubilization of naphthalene, anthracene and pyrene, in both F127 and P123 aqueous micellar solutions has been characterized by UV method. These aromatic hydrocarbons were confirmed to incorporate in the micellar cores. The model of stepwise association equilibrium was used to analyze the exper imental results and the first stepwise association constant K-1 between sol ubilizate monomer and vacant micelle was thus obtained. It was found that t he values of K-1 increased with increasing the benzene-cycle number of the aromatic hydrocarbons. The average number of solubilizating molecules corre sponding to each PO-group in the mcellar cores was verified to be consisten cy for both F127 and P123. This result suggests that the volume of the mice llar core is an important factor to determine the amount of aromatics incor porating into Pluronic micelles, The amount was lineally enhanced with incr easing the volume of the micellar core. The stability in planar-ring of the molecule of polycyclic aromatic hydrocarbon also affected its solubilizati on, It was shown by the solubilization isotherms that anthracene and pyrene have a higher efficiency in solubilization compared with naphthalene.