Generation of a carbon dots/ammonium persulfate redox initiator couple for free radical frontal polymerization

We report a new redox initiator couple of ammonium persulfate (APS)/carbon dots (CDs) with high initiation efficiency used in frontal polymerization (FP). The CDs also served as fluorescent reagents, and had good dispersion and a relatively high absolute quantum yield (>60%). The initiation efficiency and possible mechanism of CDs/peroxydisulfate (S₂O₈^2-) initiators were investigated. The electron transfer between the CDs and S₂O₈^2- made decomposition of the latter into free radicals easier. Besides, electron transfer occurred between the CDs and vinyl monomers, prompting the CDs to be applied to initiate monomers alone. Therefore, the combined effects of the CDs and APS made vinyl monomers more prone to be triggered in FP, thereby lowering the reaction temperature considerably. This research might provide a promising avenue to discover other polymerization initiators with high efficiency for the synthesis of versatile materials.