Harnessing Sacrificial Mechanical Bonds for Toughening Elastomers.

Sacrificial bonds serve as key energy-dissipating motifs, governing the toughness of elastomers. Herein, we propose a robust and versatile strategy to toughen elastomers by precisely tuning the mechanochemical reactivity of sacrificial mechanical bonds through the systematic modification of stopper structures in rotaxane crosslinkers. By varying the size and number of stoppers, the quantitative relationship between the mechanochemical response of sacrificial bonds at the molecular level and the macroscopic mechanical performance of elastomers is elucidated. This is a breakthrough that expands the practical potential of elastomers and establishes a conceptual framework for the rational design of sacrificial bonds and mechanochemicallyinspired polymer systems.