Photoinduced metal-free atom transfer radical polymerizations: State-of-the-art, mechanistic aspects and applications

Photoinduced atom transfer radical polymerization has recently been the center of intensive research in synthetic polymer chemistry because of the unique possibility of topological and temporal control in addition to precise control of macromolecular structure offered by conventional ATRP. Following the developments of new approaches to decrease the metal catalyst concentration, it was recently shown that ATRP can be carried out under metal-free conditions by using photochemical strategies. Various photocatalysts playing a role in oxidative and reductive pathways have been reported. This mini-review summarizes and highlights recent research efforts in the emerging area of photoinduced metal-free atom transfer radical polymerization. The proposed mechanisms for the activation and deactivation steps and potential applications have also been discussed.