TIRPRThiol-Induced, Light-Activated Controlled Radical Polymerization

Controlled radical polymerizations (CRPs) are one ofthe most importantways to obtain uniform, defined molecular weight polymers with complexcomposition and architecture such as block copolymers. A new controlledand light-initiated radical polymerization is introduced that makesuse of thiol initiators and an Ir-photocatalyst. Different reactionparameters are studied for their importance in the controlled characteristicsof polymerization, such as low dispersity, control of molecular weights,and straightforward access to block copolymers. The light controlfurthermore allows for simple switching on and off of the polymerization.We propose a mechanism for the so-called thiol-induced, light-activated,controlled radical polymerization (TIRP), which includes the formationof dormant species and their light- and catalyst-dependent equilibriumwith the active polymer chain end. TIRP enriches the portfolio ofcontrolled and light-initiated polymerization methods by its viabilityat mild conditions and the possibility to grow polymers from a largevariety of readily available thiols.