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<p>Ethylene-based crystalline copolymers are important materials across broad applications. However, precise control over their primary structures remains a critical challenge in advancing functional materials, limited by the intrinsic reactivity difference between ethylene and comonomers. In this work, we report the development of a light-driven organocatalyzed reversible-deactivation radical copolymerization to access well-defined ethylene-chlorotrifluoroethylene copolymer (ECTFE) under mild conditions (&lt;5 atm, 25 °C). The rational design of a three-armed phenothiazine catalyst in combination with a fluorinated dithiocarbamate furnishes good chain-growth control in the photoredox-mediated copolymerization, yielding ECTFE of excellent alternating sequence with minimized chain defects, which resulted in high crystallinity and superior melting points (up to 263.8 °C). Importantly, the obtained ECTFE exhibits outstanding chain-end activity/fidelity, enabling chain-extension (co)polymerization to access a variety of unprecedented ECTFE-based block copolymers upon visible-light exposure, which has successfully integrated rigid and soft blocks in single chains. The ease of synthesizing such block copolymers creates a versatile and convenient platform to largely tune mechanical properties, affording polymeric materials spanning from thermoplastics to elastomers via structural tailoring.</p>

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Photoredox-controlled alternating copolymerization enables highly crystalline structures and block copolymers from thermoplastic to elastomer

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年12月12日

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  • Mengli Xu,
  • Qiankai Chen,
  • Shantao Han,
  • Kaixuan Chen,
  • Xing Guo,
  • Mao Chen

摘要

Ethylene-based crystalline copolymers are important materials across broad applications. However, precise control over their primary structures remains a critical challenge in advancing functional materials, limited by the intrinsic reactivity difference between ethylene and comonomers. In this work, we report the development of a light-driven organocatalyzed reversible-deactivation radical copolymerization to access well-defined ethylene-chlorotrifluoroethylene copolymer (ECTFE) under mild conditions (<5 atm, 25 °C). The rational design of a three-armed phenothiazine catalyst in combination with a fluorinated dithiocarbamate furnishes good chain-growth control in the photoredox-mediated copolymerization, yielding ECTFE of excellent alternating sequence with minimized chain defects, which resulted in high crystallinity and superior melting points (up to 263.8 °C). Importantly, the obtained ECTFE exhibits outstanding chain-end activity/fidelity, enabling chain-extension (co)polymerization to access a variety of unprecedented ECTFE-based block copolymers upon visible-light exposure, which has successfully integrated rigid and soft blocks in single chains. The ease of synthesizing such block copolymers creates a versatile and convenient platform to largely tune mechanical properties, affording polymeric materials spanning from thermoplastics to elastomers via structural tailoring.