Xanthate-supported photo-iniferter (XPI)-RAFT polymerization: Facile and rapid access to complex macromolecular architectures

Xanthate-supported photo-iniferter (XPI)-reversible addition-fragmentation chain-transfer (RAFT) polymerization is introduced as a fast and versatile photo-polymerization strategy. Small amounts of xanthate are added to conventional RAFT polymerizations to act as a photo-iniferter under light irradiation. Radical exchange is facilitated by the main CTA ensuring control over the molecular weight distribution, while the xanthate enables an efficient photo-(re)activation. In sharp contrast to conventional photo-initiators, the xanthate is introduced into the polymer as an end group and can be used to reactivate the macromolecule, as demonstrated by the synthesis of defined multiblocks. The presented method is extremely robust, versatile, and tolerant to oxygen, and consequently multiblock-synthesis could be performed in a coffee mug under open-to-air conditions. XPI-RAFT does not rely on highly specialized equipment as demonstrated using an iPad® flashlight to drive a polymerization. Consequently, XPI-RAFT polymerization qualifies as a universal tool for the straightforward synthesis of complex macromolecular architectures.