Photoinduced ring-opening polymerizations

Photopolymerization is the subject of a growing interest both at industrial and academic levels because it provides high reaction kinetics, low emissions of volatile organic solvents and in some cases, low shrinking stress. This polymerization route has been largely developed using radical polymerization of vinyl monomers, but to a lesser extent by ring-opening polymerization (ROP). Beyond epoxides, which were the first monomers polymerized by a cationic ring-opening polymerization (CROP), the photopolymerization of other cyclic monomers has recently spread out thanks to the emergence of novel initiating systems. This review states an overview of the spectrum of cyclic monomers that have been polymerized by light-induced polymerization processes. In a first part, the photosensitive species able to trigger or to induce a change of kinetics of ROP reactions are presented according to their activation mechanism, i.e photouncaging, photoswitching or photoredox. In a subsequent part, the different monomer classes and their photopolymerization mechanisms are described with an emphasis on the properties of resulting materials. The last part covers the use of photoROP for several applications.