| Abstract: | The concentration and temperature dependencies of micelle formation by a polystyrene-block-poly(ethylene/propene) copolymer in several ketones (2-butanone, 3-pentanone, 4-methyl-2-pentanone, 4-heptanone, 5-methyl-2-hexanone and 5-methyl-3-heptanone) were studied by static and dynamic light scattering, viscometry and size exclusion chromatography. No micelles were detected in solutions of 5-methyl-3-heptanone. The standard Gibbs energy, ΔG°, the standard enthalpy, ΔH°, and the standard entropy, ΔS°, of micellization were estimated. The values of ΔG° and ΔH° were negative for all ketones studied and depended on the polar character of the ketone. The micelles showed larger association numbers and densities independent of the ketone. Micelle dimensions hardly depended on the ketone. |
