Free-radical polymerizations of and in deep eutectic solvents: Green synthesis of functional materials

The increasing environmental awareness has led to the search for alternative reaction media to reduce or eliminate the use of organic solvents in polymer science. Deep eutectic solvents (DESs), a subclass of ionic liquids, have emerged as sustainable solvents for a plethora of chemical reactions. In this Trend Article, DES utilization in free-radical polymerizations will be discussed. Two main fields of application are reported. In the first section, monomers able to undergo free-radical polymerization while taking part in a DES, as hydrogen bond donor or ammonium salt, so called DES monomers, are presented. In the second section, the role of DESs as solvents, where the polymerization takes place, either in the same phase or in an emulsion, is described. Finally, the properties of the polymers resulting from these particular methods of synthesis are discussed with emphasis on their green aspects.