Chain-Growth Click Polymerization of AB2 Monomers for the Formation of Hyperbranched Polymers with Low Polydispersities in a One-Pot Process

Hyperbranched polymers are important soft nanomaterials but robust synthetic methods with which the polymer structures can be easily controlled have rarely been reported. For the first time, we present a one-pot one-batch synthesis of polytriazole-based hyperbranched polymers with both low polydispersity and a high degree of branching (DB) using a copper-catalyzed azide-alkyne cycloaddition (CuAAC) polymerization. The use of a trifunctional AB(2) monomer that contains one alkyne and two azide groups ensures that all Cu catalysts are bound to polytriazole polymers at low monomer conversion. Subsequent CuAAC polymerization displayed the features of a living chain-growth mechanism with a linear increase in molecular weight with conversion and clean chain extension for repeated monomer additions. Furthermore, the triazole group in a linear (L) monomer unit complexed Cu-I, which catalyzed a faster reaction of the second azide group to quickly convert the Lunit into a dendritic unit, producing hyperbranched polymers with DB=0.83.