Electrochemically mediated ATRP (eATRP) allows easy modulation of the overall rate and control of polymerization through the variation of an external applied potential, Eapp. This method has been successfully applied to aqueous ATRP of oligo(ethylene glycol) methyl ether methacrylate (OEOMA475) catalyzed by Cu/TPMA. Appropriate choice of Eapp allows the synthesis of POEOMA475 with high Mw, and narrow MW distribution

Electrochemically mediated atom transfer radical polymerization (eATRP) of n-butyl acrylate was systematically\ud investigated using diminished catalyst concentrations\ud (≤300 parts per million) under a variety of formulations and\ud electrochemical conditions. Critical polymerization parameters,\ud including the applied potential, catalyst concentration,\ud and ligand, were explored and correlated with polymerization\ud rates, polymer properties, and currents during the eATRP\ud process. Additional electrochemical methods were explored to\ud improve the feasibility of eATRP under galvanostatic conditions. Copper electrodeposition and stripping experimentation proved to be an effective strategy for catalyst recycling allowing sequential controlled polymerizations to be possible utilizing one catalyst charge

The thermodynamic properties of some copper complexes, among those frequently used as catalysts in controlled/living radical polymerization, has been studied in CH3CN + 0.1 M (C2H5)4NBF4. A combination of different techniques, namely potentiometry, spectrophotometry and cyclic voltammetry, has been used to determine the stability constants of all possible complexes of CuI and CuII present in binary and\ud ternary systems composed of CuI or CuII, a halide ion (X=Cl-, Br-) and a polyamine ligand (L = pentamethyldiethylenetriamine, tris(2-dimethylaminoethyl)amine). The binary Cu-X systems show only mononuclear CuXx complexes, where x=1, 2, 3, 4 for CuII, and x=1, 2 for CuI. Conversely, in the case of the binary Cu-L systems, besides the mononuclear complexes CuLl, where l=1 or 2, also dinuclear complexes Cu2L were found. The ternary systems give rise to a mixture of mononuclear and dinuclear\ud complexes of general formula CumLlXx. Besides the 1:1:1 complex obtained in all combinations, the following species were found: CuIILX2, CuI2LX and CuI2LX2. The stability constants of all these species were determined and used to construct speciation diagrams for both CuI and CuII species. Such diagrams show that often conditions favoring the quantitative formation of CuIIL, CuIIL2, or CuIILX can be easily realized, whereas isolation of a single predominant CuI species can hardly be achieved. Speciation diagrams for CuI as a function of CX/CCuI show interesting results that may be helpful in rationalizing the role of termination reactions in atom transfer radical polymerization

This article is the first in a series of papers, describing reversible-deactivation radical polymerization (RDRP) in the presence of metallic copper. The aim of these papers is to determine the proportions and roles of Cu0, CuIBr/L, and CuIIBr2/L, and the overall reaction mechanism. This paper is focused on the comproportionation and disproportionation equilibrium between Cu0, CuIBr/L and CuIIBr2/L in dimethyl sulfoxide (DMSO) for various surface areas of Cu0 and different ligand concentrations, in both the absence and presence of methyl acrylate (MA). Comproportionation dominated disproportionation when there was enough ligand present in the reaction medium to stabilize all soluble copper species. The relative amount of CuI at comproportionation/disproportionation equilibrium increased with ligand concentration. CuI represents approximately 99.95% of all soluble Cu species in MA/DMSO = 2/1 (v/v) at the ratio [Me6TREN]0:[CuIIBr2]0 = 6:1. Under typical polymerization conditions, there is essentially no disproportionation, since the ratio [Me6TREN]:[CuII] is very large, starting from infinity and decreasing down to 6.7, for ∼3% terminated chains under the initial conditions [MA]0:[MBrP]0:[Me6TREN]0 = 222:1:0.1, in 33.3% (v/v) DMSO, with excess Cu0. The kinetics of comproportionation and disproportionation were both slow, requiring hours to reach equilibrium. The apparent rate coefficients for comproportionation and disproportionation were calculated as k comp app = 9.0 × 10–4 cm s–1 and k disp app = 2.0 × 10–5 cm s–1 in DMSO, as well as 3.5 × 10–3 cm s–1 and 3.1 × 10–6 cm s–1 in MA/DMSO = 2/1 (v/v), respectively. The results of this study invalidate the assumption of instantaneous and complete disproportionation, proposed in single-electron transfer living radical polymerization (SET-LRP). These findings agree with Cu0 acting as a supplemental activator and reducing agent in atom transfer radical polymerization (SARA ATRP).