Recent advances on photoinitiating systems designed for solar photocrosslinking polymerization reactions

Abstract

Photopolymerization is an active research field and recently, a great deal of efforts has been devoted to replace the energy-consuming UV irradiation setups by the popular and easily available energy-saving light-emitting diodes (LEDs). With aim at going a step further, sunlight can be used as an inexpensive and unlimited light source to perform polymerization processes. In this case, no energy is required anymore, and the use of photopolymerization for various outdoor applications becomes possible. Over the years, and with aim at developing reliable photoinitiating systems, various dyes have been developed, enabling in the case of sunny days to efficiently promote polymerization processes. In this review, an overview of the different photoinitiating systems developed for polymerization processes done under sunlight or even daylight is provided. Polymerization efficiency is often compared to that obtained with artificial light sources, enabling to determine the efficacy of the photoinitiating systems under sunlight.