Simultaneous Improvement of Mechanical Strength, Toughness, and Self‐healability of Elastomers Enabled by F─H‐Bond‐Based Nanoconfinement

There are often trade-offs among high mechanical strength, high toughness, and efficient self-healing. Herein, we present a biomimetic strategy utilizing F─H bonds for nanoconfinement to achieve the simultaneous enhancement of these conflicting properties. The mechanical strength, toughness, and self-healing efficiency of a fluorinated crosslinked poly(urethane-urea) (CPUU-FA) elastomer are improved 1.3-, 1.5-, and 1.2-fold, respectively, compared with those of its nonfluorinated counterpart. Notably, the CPUU-FA has the highest recorded puncture energy (887 mJ) among polymeric elastomers and the highest fracture energy (117 kJ m^-2) among reported thermoset elastomers. Moreover, it exhibits excellent self-healing efficiency (99%), remarkable reprocessability, and a low surface energy (56 MJ m^-2). The application of self-healing elastomers in the fabrication of soft electronics is further demonstrated. The molecular design strategy is anticipated to inspire new developments in high-performance materials for cutting-edge applications.