A novel strategy for synthesis of amphiphilic π-shaped copolymers by RAFT polymerization

The amphiphilic n-shaped copolymers with narrow molecular weight distribution (M-w/M-n = 1.04-1.09) based on polystyrene (PSt) and poly(ethylene glycol) have been synthesized successfully. The reversible addition-fragmentation transfer (RAFT) polymerization of St in the presence of dibenzyl trithiocarbonate and N,N'-azobis(isobutyronitrile) (AIBN) yielded macro RAFT agent PSt-SC(=S)S-PSt, subsequent reaction with excess maleic anhydride (MAh) at 80 degrees C in tetrahydrofuran afforded the PSt-MAh-SC(=S)S-MAh-PSt. It was used as RAFT agent in the RAFT polymerization of St, and finally the amphiphilic n-shaped copolymers were obtained by the reaction of MAh with hydroxyl-terminated poly(ethylene glycol methyl ether) at 90 degrees C for 48 h. Their structures were confirmed by FT-IR and H-1 NMR spectra, and their molecular weight and molecular weight distribution were measured by gel permeation chromatography. (c) 2005 Elsevier Ltd. All rights reserved.