The chemical synthesis of polymer building blocks that have varied molecular architectures and are rationally designed to self-organize or assemble into higher-order structures is critical to the design of multifaceted materials. Recently, our research has focused on the synthesis of four-armed calixarene-core polylactide (PLA)/polyethylene glycol (PEG) star block copolymers. These polymers have the potential to form aqueous micelles for use in drug-delivery applications. To prepare the new star block copolymers, a four-armed PLA star homopolymer was made by lactide ring-opening polymerization using a tetrafunctional calixarene initiator. In order to synthesize the star block copolymers, the PLA end groups were functionalized with alkynes and then coupled with an azide-functionalized PEG via a copper(I) catalyzed Huisgen dipolar cycloaddition reaction (a click reaction). Initial attempts at the coupling reaction on a NMR scale have been successful and suggest that the reaction proceeds to completion. No-deuterium (No-D) NMR spectroscopy is currently being used to optimize the quantity of PEG and catalyst needed to allow for complete coupling, while also allowing the resulting products to be easily purified. In this presentation, the synthesis of four-armed calixarene-core PLA/PEG star block copolymers will be described in detail.

Synthesis of four-armed calixarene-core polylactide/polyethylene glycol star block copolymers using click chemistry

249th National Meeting (2015)

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