Cu(0)-RDRP of acrylates using an alkyl iodide initiator

Abstract

In the vast majority of atom transfer radical polymerizations, alkyl bromides or alkyl chlorides are commonly employed as initiators, and minimal attention has been given to alkyl iodides. Herein, we report the room temperature Cu(0)-mediated reversible deactivation radical polymerization of acrylates utilizing alkyl iodide as an initiator. Kinetic experiments were conducted showing a linear dependence of M_n with conversion, good agreement between theoretical and experimental molecular weights, and low dispersity values (Đ ∼ 1.05), even at high monomer conversions. The high-end group fidelity of the iodide-terminated polymer was confirmed via MALDI-ToF-MS analysis and successful in situ chain extensions at near-quantitative conversions. Polymerization of methyl acrylate with various targeted degrees of polymerizations (DP_n = 25–2400), resulted in the synthesis of well-defined polymers with low dispersities (Đ < 1.15), even at higher molecular weights (e.g. M_n = 200 000, Đ ∼ 1.13). The compatibility of the methodology with various solvents, including acetonitrile (MeCN), dimethylformamide (DMF), acetone, and isopropanol (IPA) as well as a range of acrylic monomers was also investigated yielding polymers with excellent control over the molar mass distributions. A series of block copolymers consisting of different block segments were also synthesized in one pot without any intermediate purification steps, thus highlighting the potential of an alkyl iodide initiator in a controlled polymerization.