of the most useful properties of micelles is their ability to The solubilization of hydrocarbons by micelles formed of diblock enhance the aqueous solubility of hydrophobic substances. and symmetric triblock copolymers in water are compared in the This phenomenon, referred to as solubilization, is made posframework of a mean-field theory of solubilization. The block cosible by the incorporation of the solubilizates in the hypolymers contain poly(ethylene oxide) as the hydrophilic block drophobic microenvironment offered by the micellar core and poly(propylene oxide) as the hydrophobic block and are desig- . Because of the solubilization power of micelles, nated as E X P Y E X or E W P Z (where E and P denote ethylene and aqueous block copolymer solutions hold great promise as propylene oxides and the subscripts denote the number of segsubstituents for organic solvents in many industrial applicaments). In the presence of a variety of aromatic and aliphatic tions.
hydrocarbon solubilizates, the core radius, corona thickness, and aggregation number of the micelle and also the volume fraction
In an earlier paper (4), we presented experimental results of the hydrocarbon solubilized in the core are predicted. The calcuon the solubilization of aliphatic and aromatic hydrocarbons lations show that for identical molecular weights and block compoin micelles formed of poly(ethylene oxide) -poly(propylsitions, the diblock (E 200 P 64 ) copolymer micelles have a much ene oxide) (PEO-PPO) and poly(vinyl pyrrolidone) -polylarger core radius, corona thickness, aggregation number, and volstyrene (PVP-PS) block copolymers. Further, the selectivume fraction of the hydrocarbon solubilized in the core compared ity in the solubilization behavior was explored via measurewith the symmetric triblock (E 100 P 64 E 100 ) copolymer micelles. In ments of the solubilization capacities of benzene and hexane contrast, the diblock copolymer (E 100 P 32 ), having the same block when their binary mixtures were solubilized. Interesting recomposition but half the molecular weight of the symmetric sults displaying large solubilization capacities and high setriblock copolymer (E 100 P 64 E 100 ), gives rise to micelles having the lectivity for aromatics over aliphatics were obtained in block same core radius, corona thickness, and volume fraction of the copolymer micelles compared with conventional low-molechydrocarbon solubilized as the micelles formed of the triblock copolymer, and an aggregation number twice that of the triblock ular-weight surfactant micelles. Subsequently, we developed copolymer micelle.