Controlling the colloidal behavior of styrene-isoprene diblock copolymers by selective end functionalization

omega-Lithium poly(styrene-b-isoprene) sulfonates were synthesized by anionic polymerization. The copolymers carrying the lithium sulfonate (SuLi) end group at either the soluble or the insoluble block form a variety of different microstructures in n-decane. In the case where the SuLi group is located at the PS insoluble end block, micellar aggregates with larger aggregation number, hydrodynamic radius and thermal stability are formed, compared to the non-functionalized diblock precursor case. When the polar group is located in the soluble PI block end, the solubility of the system depends on temperature. At high temperatures where end group association primarily exists, star-like aggregates are formed. At lower temperatures PS block association also takes place, resulting in a system of highly polydisperse and interconnected aggregates. The latter materials can be considered as ABC heterotelechelic associating macromolecules presenting new ways of controlling the colloidal behavior of block copolymer systems by selective end functionalization. (c) 2006 Elsevier B.V. All rights reserved.