Evolution and Future Directions of Metal-Free Atom Transfer Radical Polymerization

The increasing impact of atom transfer radical polymerization (ATRP) in fields beyond traditional polymer science has necessitated the development of alternative strategies for controlling polymer growth. Driven by applications that are sensitive to metal ion contamination, greener methodologies are emerging as a powerful alternative to conventional ATRP. Organic catalysis represents a major evolution of ATRP with metal-free systems holding significant potential as user-friendly methods for utility in biological and microelectronic applications. In addition, shifting from a combination of thermal activation/metal ions/ligands to simpler organic catalysis/light activation increases compatibility with functional monomers and allows the development of novel surface patterning strategies. Herein, we highlight key discoveries and recent developments in metal-free ATRP, while providing a perspective for future opportunities in this emerging area.