Deep eutectic solvents (DES): Excellent green solvents for rapid SARA ATRP of biorelevant hydrophilic monomers at ambient temperature

An eco-friendly type III deep eutectic solvent (reline: choline chloride/urea) was used for the supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) of different biorelevant hydrophilic monomers (HEA: 2-hydroxyethyl acrylate, HEMA: 2-hydroxyethyl methacrylate and AMPTMA: (3-acrylamidopropyl) trimethylammonium chloride) near room temperature (30 degrees C). The polymerization of HEA mediated by a safe and inexpensive SARA agent (Na2S2O4) revealed controlled features, with polymers exhibiting low dispersity (D approximate to 1.3) throughout the course of the polymerization. Results also showed that typically, a slow and continuous feeding of the SARA agent to the reaction mixture afforded PHEA-Br with higher chain-end functionality and lower dispersity (D approximate to 1.1), in comparison to the one obtained without Na2S2O4 feeding. As proof-of-concept, purified PHEA-Br macro-initiators were used for the preparation of different well-defined block copolymers (PHEA-b-PAMPTMA and PHEA-b-PMA). (C) 2017 Elsevier Ltd. All rights reserved.