No abstract

Simplification of electrochemically mediated atom transfer radical polymerization was achieved efficiently under either potentiostatic or galvanostatic conditions using an aluminum wire sacrificial anode (seATRP) immersed directly into the reaction flask without separating the counter electrode. seATRP polymerizations were carried out under different applied potentials, Eapps = E1/2, Epc, Epc -40 mV, and Epc -80 mV. As the rate of polymerization (Rp) can be modulated by applying different Eapp potentials, more reducing conditions resulted in faster Rp. The polymerization results showed similar narrow molecular-weight distribution throughout the reactions, similar to results observed for n-butyl acrylate (BA) polymerization under conventional eATRP. High-molecular-weight PBA and diblock copolymers were synthesized by seATRP with more than 90% monomer conversion. Furthermore, galvanostatic conditions were developed for synthesizing PBA with the two-electrode system.

In contrast with previous accounts, it is reported that a single, strongly hydrophilic Cu complex can control an electrochemically mediated atom transfer radical polymerization (eATRP) in oil-in-water miniemulsion in the presence of anionic surfactants, such as sodium dodecyl sulfate (SDS). The anionic surfactant interacted strongly with cationic copper complexes, enabling controlled polymerization by a combination of “interfacial” and “ion-pair” catalysis, whereby ion pairs transport the catalyst to the monomer droplets. The ion-pair system was assembled in situ by mixing commercially available reagents (NaBr, SDS, and traditional hydrophilic copper complexes). Polymer purification was very facile because after reaction >99% of the hydrophilic copper complexes spontaneously left the hydrophobic polymer particles.