TIRPThiol-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.

Automated summary

Controlled radical polymerizations (CRPs) are an important method for obtaining uniform and defined molecular weight polymers with complex composition and architecture. A new controlled and light-initiated radical polymerization using thiol initiators and an Ir-photocatalyst is introduced. Different reaction parameters are studied for their importance in achieving controlled characteristics of polymerization, such as low dispersity and control of molecular weights, and the ability to access block copolymers easily. The proposed mechanism for thiol-induced, light-activated, controlled radical polymerization (TIRP) involves the formation of dormant species and their equilibrium with the active polymer chain end, which is dependent on light and catalyst. TIRP expands the range of controlled and light-initiated polymerization methods by its mild conditions and the ability to grow polymers from a variety of readily available thiols.