Expanding the Scope of the Photoinduced Living Radical Polymerization of Acrylates in the Presence of CuBr₂ and Me₆-Tren

Abstract

Photoinduced living radical polymerization of acrylates is achieved upon UV irradiation (λ max ≈ 360 nm) in the presence of an aliphatic tertiary amine ligand (Me 6 -Tren) in the presence of low concentrations of CuBr 2, yielding poly(acrylates) with near perfect retention of end group fidelity. The effect of the nature of the solvent on the rate of polymerization was investigated in order to expand the scope and identify the limitations of the system. Subsequently, a range of acrylic monomers containing hydrophobic and hydrophilic substituents have been screened, including lauryl acrylate, octadecyl acrylate and diethylene glycol ethyl ether acrylate, all of which present low dispersities ( Đ ≈ 1.1) at very high conversions. Functional monomers, including glycidyl acrylate and solketal acrylate, were also found to be tolerant to the photomediated reaction. Finally, solketal acrylate was copolymerized with methyl acrylate which, following deprotection of the pendant ketal group, furnished an amphiphilic diblock copolymer. Self-assembly of this block copolymer into polymer micelles in aqueous media was exemplified by dynamic light scattering (DLS) and transmission electron microscopy (TEM).