Expanding the use of affordable CuSO4·5H2O in ATRP techniques in homogeneous media

Abstract

Advances in atom transfer radical polymerization (ATRP) are usually focused on reducing the metal catalyst concentration, using low toxicity metals or even metal-free catalysts, to minimize or avoid the contamination of polymers. In this work, the less toxic and inexpensive CuSO4·5H2O was used to replace CuBr2, the most employed metal source for ATRP, to control polymerizations under homogeneous conditions. Well-defined (Đ ≤ 1.3) hydrophobic homopolymers of poly(methyl acrylate) (PMA), poly(methyl methacrylate) (PMMA), polystyrene (PS) and poly(butyl acrylate) (PBA) were obtained in various organic solvent/water mixtures with similar control as when CuBr2 was used. The main limitation is the lower solubility of the CuSO4/L complex in pure organic solvents compared with CuBr2/L. The preparation of several hydrophilic polymers, namely poly(2-hydroxyethyl acrylate) (PHEA), poly((3-acrylamidopropyl)trimethylammonium chloride) (PAMPTMA), poly(2-hydroxyethyl acrylamide) (PHEAA), polyacrylamide (PAAm), poly(N,N-dimethylacrylamide) (PDMAA), poly(2-aminoethyl methacrylate hydrochloride) (PAMA), poly[oligo(ethylene oxide) methyl ether acrylate] (POEOA) and biorelevant block copolymers (PHEA-b-PAMPTMA and PAMPTMA-b-PHEAA) was successfully carried out in aqueous medium using different ATRP techniques. Future studies on this system will include the use of CuSO4/L complexes in several organic solvents and in heterogeneous ATRP.