Synthetic strategies for the generation of ABCA' type asymmetric tetrablock terpolymers

Abstract

We report the synthesis of poly(lactide)-b-poly(styrene)-b-poly(butadiene)-b-poly(lactide) (LSBL′) and poly(styrene)-b-poly(isoprene)-b-poly(ethylene oxide)-b-poly(styrene) (SIOS′) tetrablock terpolymers with asymmetrically sized end blocks. A combination of anionic polymerization and ring opening transesterification polymerization (ROTEP) of (±)-lactide was used to synthesize LSBL′ while SIOS′ was prepared by a combination of anionic polymerization and reversible addition–fragmentation chain transfer (RAFT) polymerization. All intermediate and final products were characterized by size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR) techniques and specific control experiments for the LSBL′ tetrablock confirmed the successful synthesis.