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Block copolymer micelles formed by diblock and triblock copolymers of styrene and methacrylic acid were characterized in solution in a mixed solvent with 80 vol % of dioxane and 20 vol % of water. Methods of static light scattering, quasielastic light scattering, differential refractometry, viscometry, sedimentation velocity, and densitometry were used. No unattached unimer molecules were observed. Three independent methods were employed for obtaining micellar weights. They agreed well with each other. No anomalous behavior was observed by any method. The micellar solutions were shown to contain almost exclusively single micelles; only a few samples (those producing the largest micelles) contained micellar clusters. The micelles behaved hydrodynamically and thermodynamically as impermeable spheres. The structure of the micellar shell was characterized in some detail. Relations between the aggregation number and the hydrodynamic radius of the micelles on the one hand and the sizes of the styrene and methacrylic acid blocks on the other were presented as scaling type phenomenological equations.Physicochemical properties of self-assembling molecules are of ever increasing experimental and theoretical interest. This is not only due to the intriguing phenomenon of selfassembling but also due to important applications of such materials in coatings, adhesives, thin films, microfabrication of electronic devices, pharmaceutical and photographic technologies, oil recovery, etc. Among the most important self-assembling systems are polymeric micelles.

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Inverse gas chromatography has been used to measure specific retention volumes and to derive a comprehensive set of interaction parameters for 9 polymers and 43 solvents at 6 temperatures from 60 to 110 °C. The specific retention volume, the Flory-Huggins interaction parameter %i2, and the excess cohesive energy parameter Bi2 are presented for each polymer-solvent system as a function of temperature.

Block copolymers, when dissolved in a selective solvent, form spherical micelles. These micelles can selectively solubilize organic molecules otherwise insoluble in the pure solvent. In this study, we report solubilization of organic molecules by styrene‐methacrylic acid block copolymer micelles in aqueous buffers. A light scattering technique was developed to determine the extent of micellar solubilization. Our results indicate that the extent of micellar solubilization depends on the chemical nature of organic molecules, specifically, on the interactions between the organic compound and polystyrene. A thermodynamic model has been developed to describe micellar solubilization. The theoretical calculation agrees reasonably well with the experimental results for two micellar samples examined. ©1995 John Wiley & Sons, Inc.