MICELLIZATION OF POLYSTYRENE-B-POLY(ETHYLENE BUTYLENE)-B-POLYSTYRENE TRIBLOCK COPOLYMERS IN 4-METHYL-2-PENTANONE

The micellization thermodynamics, micelle structural parameters, and m icelle size distribution for olystyrene-b-poly(ethylene/butylene)-b-po lystyrene copolymer solutions in 4-methyl-2-pentanone were studied. Th e solvent used is selective for the outer PS blocks of the copolymer. Standard Gibbs energy, standard enthalpy, and standard entropy of mice llization were determined from Light scattering measurements. The infl uence of the copolymer. molar mass on these magnitudes was analyzed. T he structural parameters of micelles formed by different triblock copo lymers were determined by static light scattering. Micelle molar mass and size increase with the length of the copolymer chain for a constan t copolymer composition; however the association number decreases. Mic elle size distribution functions were obtained from dynamic light scat tering and size exclusion chromatography measurements. The results obt ained by means of both techniques were compared.