Synthesis of amphiphilic polystyrene–ionene diblock copolymers with controlled block lengths

Abstract

AbstractAmphiphilic polystyrene‐ionene diblock copolymers with blocks of controlled molecular weights were synthesized by a new method. The preparation starts with the anionic polymerization of styrene with 3‐(dimethylamino)propyl‐lithium as initiator, yielding tertiary amino end‐functionalized polystyrenes of molecular weights that can be varied over a wide range from 1 to 100kg/mol, and a relatively low polydispersity (M̄w/M̄n = 1.1–1.4). The crucial step in this method is the stepwise coupling of the reactive end‐group of the polystyrene with bromo‐ and tertiary‐amino‐terminated monodisperse oligomeric 2,4‐ionenes. The amphiphilic polymers with well‐defined block lengths were characterized by thin‐layer chromatography, end‐group titration and elemental analysis. Amphiphilic block copolymers with a monodisperse ionene block consisting of up to 10 quaternary ammonium groups could be derived.