Photoinitiated metal free living radical and cationic polymerizations

Although conventional photoinitiated radical and cationic polymerizations are widely used in many industrial applications, they usually proceed in an uncontrolled manner. Recent developments in photomediated living/controlled radical and cationic polymerization made it possible to prepare various well-defined polymers with complex architecture under mild conditions. Various methods described for cationic and radical polymerization utilizes metal or Lewis acid catalysts. Several strategies eliminating the use of such additives in photoinduced controlled/living radical and cationic polymerizations have been developed. This article describes various photoinitiation systems acting in UV-vis range. Their mechanistic details are also evaluated and several specific examples involving combination both free radical and cationic routes are presented.