Solution Properties of a Diblock Copolymer in a Selective Solvent of

Macromolecules 1994,27, 4561-4565

4561

Solution Properties of a Diblock Copolymer in a Selective Solvent of Marginal Quality. 2. Characterization of Micelles and Surface Tension D. F. Siqueirat and S.P.Nuned Institute of Chemistry, Universidade Estadual de Campinas, 13081 Campinas-SP, Brazil

B. A. Wolf" Institut fiir Physikalische Chemie, Johannes Gutenberg Universitat, 0-55099 Mainz, Germany

Received November 16, 1993; Revised Manuscript Received May 17, 1994. ABSTRACT. Solutionsof polystyrene-block-poly(buty1methacrylate)[P(S-b-BMAI-a narrowly distributed linear diblockcopolymer consistingof 1200monomericunitsof styreneand 1200unitsof butyl methacrylate-in 2-propanol (a nonsolvent for the S blocks and a 0 solvent (0 = 23 "C)for the BMA blocks) were studied by carring out the following measurements: dynamic (DLS) and static light scattering (SLS), transmission and surfacetension. The results demonstrate eldronmicroscopy (TEM),small-angleX-ray scattering(SAXS), that the polymer forms micelles as soon as a very low critical micelle concentration (