Hetero and homo α,ω-chain-end functionalized polyphosphazenes

The control of chain-ends is fundamental in modern macromolecular chemistry for directed one-to-one bioconjugation and the synthesis of advanced architectures such as block copolymers or bottlebrush polymers and the preparation of advanced soft materials. Polyphosphazenes are of growing importance as elastomers, biodegradable materials and in biomedical drug delivery due to their synthetic versatility. While controlled polymerization methods have been known for some time, controlling both chain-ends with high fidelity has proven difficult. We demonstrate a robust synthetic route to hetero and homo alpha,omega-chain-end functionalized polyphosphazenes via end-capping with easily accessible, functionalized triphenylphosphine-based phosphoranimines. A versatile thiol-ene click-reaction approach then allows for subsequent conversion of the end-capped polymers with various functional groups. Finally, we demonstrate the utility of this system to prepare gels based on homo alpha,omega-chain-end functionalized polyphosphazenes. This development will enhance their progress in various applications, particularly in soft materials and as degradable polymers.

Automated summary

Polyphosphazenes are versatile compounds that can be used for bioconjugation, advanced structure synthesis, and material preparation. We developed a method for synthesizing functionalized polyphosphazenes through end-capping and click reactions. This method can be used to prepare gels based on polyphosphazenes.