Electrochemically Mediated Atom Transfer Radical Polymerization

Abstract

Atom transfer radical polymerization is a versatile technique for exerting precise control over polymer molecular weights, molecular weight distributions, and complex architectures. Here, we show that an externally applied electrochemical potential can reversibly activate the copper catalyst for this process by a one-electron reduction of an initially added air-stable cupric species (Cu(II)/Ligand). Modulation of polymerization kinetics is thereby tunable in real time by varying the magnitude of applied potential. Application of multistep intermittent potentials successfully triggers initiation of polymerization and subsequently toggles the polymerization between dormant and active states in a living manner. Catalyst concentrations down to 50 parts per million are demonstrated to maintain polymerization control manifested in linear first-order kinetics, a linear increase in polymer molecular weight with monomer conversion, and narrow polymer molecular weight distributions over a range of applied potentials.

Solvent dependent anion dissociation limits copper(i) catalysed atom transfer reactions

“…18 Our own work has demonstrated that activation may be driven electro-catalytically. 19 Figure 1) the weakly bound axial solvent ligand is easily displaced (broken lines, Figure 1).…”

Kinetic Modeling of ICAR ATRP

“…In the past few years, several modified ATRP techniques have been developed that enable the synthesis of well-defined (co)polymers using very low concentrations of copper catalyst (1-200 ppm). Among these, initiators for continuous activator regeneration (ICAR) [15] and activator regenerated by electron transfer (ARGET) [16][17][18] ATRP and the recently developed electrochemically mediated ATRP [19] (eATRP) techniques can have a significant impact on the industrial applicability of ATRP.…”

Computer‐Aided Optimization of Conditions for Fast and Controlled ICAR ATRP of n‐Butyl Acrylate

“…Even though selection of the appropriate ATRP catalyst enables the synthesis of well-defined polyacrylates and purification methods are available for its removal, [37][38][39][40][41] the amount of catalyst in a normal ATRP process is too high to obtain an economic profitable process. [1,42] Therefore, in the last years, ATRP modified techniques [5,[43][44][45][46][47][48][49][50][51][52][53][54] have been developed in which a low catalyst concentration (ppm level with respect to monomer) is employed. Importantly, these techniques can be applied using commercially available ligands, are more environmentally friendly and avoid the oxygen sensitivity of the activator upon storage.…”