Direct Transformation of Living Anionic Polymerization into RAFT-Based Polymerization

Abstract

A method of direct switching from anionic polymerization into RAFT-based polymerization was developed. The transformation involved in situ addition of living carbanionic species, end-capped with DPE, toward CS2 and subsequent reaction with alkyl bromides, resulting in macro-RAFT agents (macro-CTAs). The macro-CTAs were used to mediate RAFT polymerization of (functional) vinyl monomers. These processes were performed in a continuous way without isolation of the intermediate. Diblock or ABA-type triblock copolymers, composed of polydiene segment and functional acrylate (2-hydroxyethyl acrylate, HEA) or acrylamide (N-isopropylacrylamide, NIPAM), were synthesized by RAFT polymerization mediated by PI macro-CTAs. The successful preparation of block copolymers was demonstrated by the self-assembly of amphiphilic diblock copolymer PI75-b-PNIPAM199 in water (selective solvent for PNIPAM) or heptane (selective solvent for PI). The obtained block copolymers are cleavable into homopolymer components due to the prese...