(303c) Synthesis of Novel Nanostructured Copolymers with Alternating Linear Polymer and Dendrimer Blocks

Linear polymers and dendrimers are essential classes of polymers that have been intensively investigated over the past decades. In particular, with monodispersity and well-defined nanoscopic morphologies, dendrimers are also important modules for nanoscale polymer syntheses. A variety of macromolecular architectures using dendrimers as building blocks have been studied. However, nanostructured copolymers with alternating linear polymer and dendrimer blocks so far have not been reported. Herein the synthesis of such a novel alternating copolymer composed of dendrimer and linear poly(ethylene glycol) (PEG) blocks via click chemistry is presented. Firstly, poly(thio-ether) dendrimers with two azide functional groups were synthesized via a robust and efficient divergent approach based on alternating thiol-ene and esterification reactions. Subsequently, the alkyne-azide click reactions of α,ω-diacetylene PEGs with the functional dendrimers were performed to yield the linear-dendrimer alternating copolymers with high molecular weight. Both the final alternating copolymers and the polymeric precursors were systematically characterized. The self-assembly properties of the alternating copolymers were studied using microscopy techniques. Unusual assembled nanostructures, such as nanotubes, were observed. Overall, this work elucidated an innovative approach for the synthesis of a new type of dendrimer-based nanostructured polymer, and this approach may potentially be expanded and utilized to access a broad variety of novel nanostructured polymers.