Internal catalysis significantly promotes the bond exchange of covalent adaptable polyurethane networks.

Huang, Hongfei; Sun, Wei; Sun, Lijie; Zhang, Luzhi; Wang, Yang; Zhang, Youwei; Gu, Shijia; You, Zhengwei et al. · Proc Natl Acad Sci U S A · 2024

basic_science · Level V

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Abstract

Self-healing covalent adaptable networks (CANs) are not only of fundamental interest but also of practical importance for achieving carbon neutrality and sustainable development. However, there is a trade-off between the mobility and cross-linking structure of CANs, making it challenging to develop CANs with excellent mechanical properties and high self-healing efficiency. Here, we report the utilization of a highly dynamic four-arm cross-linking unit with an internally catalyzed oxime-urethane group to obtain CAN-based ionogel with both high self-healing efficiency (>92.1%) at room temperature and superior mechanical properties (tensile strength 4.55 MPa and toughness 13.49 MJ m<sup>-3</sup>). This work demonstrates the significant potential of utilizing the synergistic electronic, spatial, and topological effects as a design strategy for developing high-performance materials.