Visible Light Mediated Controlled Radical Polymerization in the Absence of Exogenous Radical Sources or Catalysts

Abstract

The application of external stimuli such as light to induce controlled radical polymerization reactions has important implications in the field of materials science. In this study, the photoactivation of trithiocarbonates (TTCs) (i.e., conventional RAFT agents) by visible light (∼460 nm) is investigated, and the ability of TTCs to control radical polymerization under visible light in the complete absence of exogenous photoinitiators or catalysts is demonstrated for the first time. By selectively exciting the spin-forbidden n → π* electronic transition, polyacrylates and polyacrylamides of low dispersity and high end group fidelity were obtained. In addition, this approach allows for the efficient synthesis of well-defined linear, (multi)block, and network (co)polymers. This study demonstrates the versatility of our strategy to generate polymers with controllable properties by visible light, which may be highly useful for applications such as surface patterning.