Design of water-soluble block copolymers containing poly(4-vinylpyridine) by atom transfer radical polymerization

The preparation of block copolymers consisting of poly(4-vinylpyridine) (P4VP) by atom transfer radical polymerization (ATRP) was investigated. The goal was to synthesize water-soluble block copolymers with poly(ethylene oxide) (PEO) as first block, a water-soluble polymer at any pH. First, a PEO macroinitiator was prepared for the ATRP block copolymerization of 4-vinylpyridine. In the second stage, the kinetic behaviour of this block copolymerization was investigated for two different types of PEO-macroinitiators and catalyst systems, based on CuCl or CuCl₂/Cu(0), with tris[2-(dimethylamino)ethyl]amine (Me₆-TREN) as the ligand. Various combinations of initiator and catalyst led to a controlled block copolymerization with optimized results obtained for chlorinated poly(ethylene glycol) monomethyl ether as macroinitiator, together with CuCl₂/Cu(0)/Me₆-TREN as catalyst system. With the latter system, narrow polydispersities (1.25) could be reached for PEO-P4VP block copolymers.