Figure 4.
Thiol-ene photoclick chemistry is a mild and efficient reaction for hydrogel formation and functionalization. a) The thio-ene reaction mechanism, showing the cycle of propagation (thiyl radical addition to alkene) and chain transfer to generate a new thiyl radical. b) Under ambient conditions and identical photoinitiating schemes and functional group concentrations, hydrogels are formed by the thiol-ene reaction within 5 s; comparatively, hydrogels formed by homopolymerization of PEG-diacrylate are delayed. Reproduced from McCall et al.104 Copyright (2012) American Chemical Society.