Synthesis of Amphiphilic ABC Triblock Copolymers by Single Electron Transfer Nitroxide Radical Coupling Reaction in Tetrahydrofuran

A series of ABC triblock copolymers, that is, polyisoprene-block-polystyrene-block-poly(ethylene oxide) (PI-PS-PEO), PI-block-poly(tert-butyl acrylate)-block-PEO (PI-PtBA-PEO), and PI-block-poly(acrylic acide)-block-PEO (PI-PAA-PEO) were obtained by combination of anionic technique, atom transfer radical polymerization (ATRP), and single electron transfer nitroxide coupling (SETNRC) reaction. Anionic polymerization of isoprene followed by end capping with ethylene oxide yielded hydroxyl-terminated PI. After esterification, PI with Br end group was used as a macroinitiator to initiate the polymerization of styrene and tBA by ATRP that was then trapped by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) group in PEO by SETNRC reaction rapidly with high efficiency in tetrahydrofuran at room temperature. The effect of reaction time and polymer chain length on SETNRC reaction was discussed in detail. In the presence of Cu(0)/tris[2-(dimethylamino) ethyl] amine, SETNRC between PI-PS-Br and PEO-TEMPO was carried out with the efficiency of up to 91.6% in 2 h. With the increase in polymer chain length, the efficiency decreased fleetly. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 2802-2810, 2011