Inside Back Cover: Segmented Polyurethane Elastomers with Mechanochromic and Self‐Strengthening Functions (Angew. Chem. Int. Ed. 15/2021)

Mechanofunctional polymers that exhibit color change, fluorescence, and self‐strengthening ability were developed by Hideyuki Otsuka et al. in their Communication on page 8406. It is the first example of force‐induced cross‐linking reactions achieved by only the extension or compression of a bulk film. The cross‐linking reaction can be visualized via color change and fluorescence and evaluated by electron paramagnetic resonance spectroscopy.