Atom Transfer Radical Polymerization: A Mechanistic Perspective

Abstract

Since its inception, atom transfer radical polymerization (ATRP) has seen continuous evolution in terms of the design of the catalyst and reaction conditions; today, it is one of the most useful techniques to prepare well-defined polymers as well as one of the most notable examples of catalysis in polymer chemistry. This Perspective highlights fundamental advances in the design of ATRP reactions and catalysts, focusing on the crucial role that mechanistic studies play in understanding, rationalizing, and predicting polymerization outcomes. A critical summary of traditional ATRP systems is provided first; we then focus on the most recent developments to improve catalyst selectivity, control polymerizations via external stimuli, and employ new photochemical or dual catalytic systems with an outlook to future research directions and open challenges.

Open-air green-light-driven ATRP enabled by dual photoredox/copper catalysis

“…Then, in the reverse reaction, the propagating radical reacts with the X-Cu II /L, recovering the active form of the catalyst (Cu I /L) and the dormant chain end (C(sp 3 )-X). [10][11][12] A limitation of ATRP, like any other RDRP technique is its sensitivity to oxygen, as both initiating and propagating radicals are quenched by oxygen. Furthermore, molecular oxygen can oxidize an ATRP catalyst to its inactive form, inhibiting polymerization.…”

Electrochemical Investigation of Iron-Catalyzed Atom Transfer Radical Polymerization

“…Reversible deactivation radical polymerization (RDRP) techniques allow for the preparation of polymeric materials with precisely tailored architectures, low dispersity and well-preserved chain end functionality [ 1 ]. Among these methods, the most important and widely used techniques are atom transfer radical polymerization (ATRP [ 2 , 3 , 4 ]), reversible addition fragmentation chain transfer polymerization [ 5 , 6 ] and nitroxide-mediated polymerization [ 7 , 8 ]. The success of these methods relies on establishing a dynamic equilibrium between the propagating radical and a dormant species, which drastically reduces the rate of termination reactions, resulting in a remarkable increase in radical lifetime.…”

Scaling-Up an Aqueous Self-Degassing Electrochemically Mediated ATRP in Dispersion for the Preparation of Cellulose–Polymer Composites and Films

“…The compelling and ever-growing need for greener applications is one of the recognized ways to make ATRP a tool of ecological transition [8]. The need for sustainable chemistry, green materials, and improved chemical synthesis led us to focus on a way to scale up ATRP using cellulose as a starting substrate, providing reactors and reactions as close as possible to their industrial implementation [6,9]. ATRP gives the opportunity to design well-defined and often complex polymer structures.…”

“…ATRP gives the opportunity to design well-defined and often complex polymer structures. ATRP is a catalytic process usually mediated by Cu complexes and is tolerant to a variety of functional groups, solvents [9], and more recently oxygen [10][11][12][13][14]. Active copper catalysts with strong negative reduction potential allowed for well-controlled polymerizations at catalyst loadings as low as 10-100 parts per million (ppm), based on monomer concentration, in H 2 O and organic solvents.…”

“…Polymers 2022, 14, x FOR PEER REVIEW 2 sustainable chemistry, green materials, and improved chemical synthesis led us to f on a way to scale up ATRP using cellulose as a starting substrate, providing reactors reactions as close as possible to their industrial implementation [6,9]. ATRP gives the portunity to design well-defined and often complex polymer structures.…”