BLOCK-COPOLYMER MICELLES IN SOLUTIONS OF A HOMOPOLYMER - DYNAMIC LIGHT-SCATTERING AND VISCOSITY STUDIES

Solutions of polystyrene-b-poly(ethylene/propylene) block copolymer an d homopolystyrene in toluene (a good solvent of both copolymer blocks) were studied by dynamic light scattering and viscometry. The presence of homopolystyrene in the solution induces the formation of micelles with a core which consists of poly(ethylene/propylene) blocks. The dyn amic light scattering measurements showed that these micelles have a n arrow size distribution. The influence of the polystyrene concentratio n on the structural parameters of the micelles was analysed. The hydro dynamic radius and molar mass remained constant in the polystyrene con centration range studied. However, the diffusion of the micelles was v ery influenced by the increment of the solution viscosity caused by th e polystyrene chains. Copyright (C) 1996 Elsevier Science Ltd.