Photo‐Organocatalyzed Synthesis of Hard‐Soft‐Hard Triblock Copolymers From Tetrafluoroethylene: Facile Access to Hydrogen‐Bonded Thermoplastic Fluoroelastomers

Abstract

ABSTRACT Thermoplastic elastomers (TPEs) combine the re‐processability of thermoplastics with the elasticity of rubbers, representing a pivotal class of polymer materials for sustainable and versatile applications. Fluoroelastomers relying on covalently cross‐linked networks, by contrast, achieve their superior performance at the expense of re‐processability and recyclability. In this work, we report a versatile photoredox‐mediated reversible‐deactivation radical copolymerization of tetrafluoroethylene (TFE) with functional comonomers, enabled by designing a fluorobenzonitrile‐based photocatalyst (PC) exhibiting thermally activated delayed fluorescence ( E 1/2 (PC/PC •− ) = −1.87 V, τ TADF = 54.06 µs). At ppm‐level catalyst loading, this system affords well‐defined TFE copolymers bearing diverse nucleophilic pendants, including urethane, ureido, and thiocarbamide moieties, while maintaining excellent chain‐growth regulation and high chain‐end fidelity. Such hydrogen‐bonding pendants within the TFE copolymers promote the formation of dynamic hard segments. Leveraging this platform, we developed a two‐step sequence comprising photo‐mediated polymerization and chain extension without altering photocatalytic conditions, allowing the streamlined synthesis of hard‐soft‐hard triblock copolymers. Notably, the sequence‐controlled materials function as thermoplastic fluoroelastomers (TPFEs) with outstanding re‐processability, self‐healing capability, and tunable mechanical strength. This work establishes a molecular‐level engineering approach to high‐performance and sustainable TPFEs, opening doors for advanced materials.