Light-Induced Disintegration of Robust Physically Cross-Linked Polymer Networks

Authors

  • Congcong Zhu,

    1. Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
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  • Christopher J. Bettinger

    Corresponding author
    1. Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
    2. McGowan Institute of Regenerative Medicine, Pittsburgh, PA
    • Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
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E-mail: cbetting@andrew.cmu.edu

Abstract

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Photodegradable physically cross-linked polymer networks are prepared from self-assembly of photolabile triblock copolymers. Linear triblock copolymers composed of poly (o-nitrobenzyl methacrylate) and poly(ethylene glycol) (PEG) segments of variable molecular weights were synthesized using atom transfer radical polymerization. Triblock polymers with low-molecular-weight PEG segments form solid films upon hydration with robust mechanical properties including a Young's modulus of 76 ± 12 MPa and a toughness of 108 ± 31 kJ m−3. Triblock polymers with high-molecular-weight PEG segments form physically cross-linked hydrogels at room temperature with a dynamic storage modulus of 13 ± 0.6 kPa and long-term stability in hydrated environments. Both networks undergo photodegradation upon irradiation with long wave UV light.

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