Micellization of a radial copolymer with four polystyrene‐block‐polybutadiene branches

Similarly to the three‐block copolymer poly(styrene‐ b ‐butadiene‐ b ‐styrene), a radial block copolymer with four brances consisting of inner polybutadiene and outer polystyrene blocks forms, in a mixed solvent tetrahydrofuran/ethanol, spherical micelles with a polybutadiene core and polystyrene shell. The equilibrium between these micelles and the molecularly dissolved copolymer was studied as a function of the solvent composition by means of light scattering, sedimentation velocity, and GPC. The sedimentation diagrams were interpreted taking into account the Gilbert theory of mobile equilibrium in systems of associating macromolecules.