Enhancing the Reactivity of Mechanically Responsive Units via Macromolecular Design

The field of polymer mechanochemistry has experienced a rapid growth in the past two decades because of the establishment of the concept of mechanophores, which describes mechanically active molecular units. A wide variety of mechanophore functions have been developed, and these are expected to evolve into practical applications. In particular, self-reporting mechanochromism in glassy polymers, thermoplastic elastomers, and polymer networks has been extensively explored. However, owing to the low reaction efficiency of mechanophores in bulk materials, the induced property changes are restricted to optical properties. Recent studies have revealed that the macromolecular design contributes more substantially to the mechanochemical sensitivity and efficiency than the fine-tuning of the mechanophore structure itself. This Perspective aims to provide an overview of strategies based on the macromolecular design to transfer force efficiently to mechanophores through polymer chains.