Electrosynthesis and electrocatalysis are fundamental tools for chemical transformations, switchable catalysis, and external regulation of controlled polymerizations. For example, electrochemically mediated atom transfer radical polymerization (eATRP) allows for the growth of well-defined polymers with designed dispersity as well as under external temporal and spatial control. Since its inception in 2011, the setup of eATRP has been significantly simplified, so that inexpensive electrode materials can be used without any separation between anodic and cathodic compartments. This led to the preparation of well-defined polymeric architectures such as stars and multiblock co-polymers, gradient and patterned polymer brushes, as well as bioconjugates and electrochemical sensors. eATRP has also been applied to heterogeneous polymerization systems (miniemulsions), by shuttling the electrochemical stimulus from an electrode to monomer droplets. The miniemulsion catalytic system allowed for an extremely low polymer contamination, with ppb of residual copper catalyst. From the successful eATRP procedure, an electrochemically mediated RAFT (eRAFT) was recently developed. eRAFT was triggered by electrochemical reduction of traditional radical initiators, diazonium salts, or electron donors, with control over reaction rate and on/off procedures. eRAFT and eATRP can be combined in dual/concurrent systems—ATRP catalysts are used to activate RAFT agents and to produce radical species. In the field of ATRP, electrochemistry has also been used as a powerful instrument to study mechanism and kinetics of the process. ATRP activation rate constants and equilibrium constants has been investigated in a range of 12 orders of magnitude, from the slow reaction of traditional bipyridine-based catalysts, to the diffusion-controlled reaction of modern catalytic systems. Electrochemical tools have also been applied to the study of extremely reactive photocatalysts in their excited states.

Electrochemical control of reversible-deactivation radical polymerizations

256th National Meeting (2018)

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