Degradable Phosphorus–Nitrogen Cage-Containing Hybrid Polymers via Activated Alkyne-Hydroxyl Click Polymerization

Abstract Phosphorus–nitrogen (PN) cage-containing polymers represent a promising class of hybrid materials that combine the structural rigidity and thermal robustness of inorganic frameworks with the processability of organic macromolecules. However, their development remains limited by the lack of efficient and modular synthetic approaches, with current strategies largely relying on the Staudinger reaction, which suffers from slow kinetics and harsh reaction conditions. Herein, we report a rapid and convenient route to PN cage-containing polymers via organic base-catalyzed hydroxyl-yne click polymerization. This method enables the synthesis of a library of poly(phosphazene vinyl ether ester)s under mild conditions with high efficiency and broad monomer scope. The resulting materials exhibit high thermal stability (Td between 310 and 325 °C, char yields up to 61%) and tunable surface wettability. Notably, degradation studies reveal that incorporation of the PN cage significantly accelerates the acid-catalyzed hydrolysis of the vinyl ether backbone, a transformation that remains kinetically hindered in analogous cage-free systems. This work establishes a versatile platform for the integration of PN cages into polymer architectures and highlights their active role in modulating polymer reactivity and properties.