Controlled/"Living" Click Polymerization with Possible Bi-Directional Chain-Growth Propagation during Polyaddition

In this work, we found a new class of controlled/"living" polymerization system, which proceeds bidirectional fashion using click reaction of AB monomer bearing azide and alkyne functionalities in a single molecule. The click polymerization of the AB monomer proceeded well using both azide and alkyne initiators in a well-controlled manner in either growth direction to afford polymers with predetermined molecular weights and narrow molecular weight distributions as well as the terminal structures inherited from the initiator. Especially, the polymerizations with the difunctional initiators provided well-defined linear polymers with azide or alkyne groups at both termini. This approach also allows for polymerization control over the second monomer to give a block copolymer.