Overview of Click Polymerization

Abstract

Click polymerizations with remarkable advantages have been nurtured into powerful polymerization techniques with widespread applications. In this overview, several types of click polymerizations and their applications are briefly summarized. Of these, azide–alkyne click polymerizations (AACPs) are the most widely used due to the easy availability of the monomers and the stability of the products. AACPs catalyzed by Cu(i) and Ru(ii) can offer 1,4- and 1,5-regioregular PTAs, respectively. Meanwhile, 1,4-regioregular PTAs can also be obtained via metal-free click polymerizations of activated alkynes and azides or activated azides and alkynes. 1,5-regioregular PTAs can be produced by organic base-mediated AACP. Thiol-ene click polymerizations are versatile tools for the preparation of polythioethers with linear and hyperbranched structures. Similarly, thiol-yne click polymerizations, as the updated version of the former, can provide polythioethers and poly (vinyl sulfide)s (PVSs) with diverse structures. Novel reversible polymers can be yielded via Diels–Alder click polymerizations. Some new click polymerizations have also been researched for the synthesis of functional polymers with various structures. With these efficient polymerization techniques in hand, polymer scientists have prepared a large number of polymers with unique properties, such as luminescence, photonic patterning, adjustable light refractivity, optical nonlinearity, biodegradability, catalyst activity, self-assembly and self-healing.