Highly Stretchable Tough Elastomers Crosslinked by Spiropyran Mechanophores for Strain‐Induced Colorimetric Sensing

Abstract

Abstract Colorimetric spiropyran as a promising mechanophore has proven to be useful in visualizing stress/strain sensing and damage warning in polymeric materials. However, it remains challenging to prepare spiropyran‐containing mechanochromic materials with excellent mechanical properties. Herein, highly stretchable and tough double‐network elastomers crosslinked by spiropyran mechanophores are reported. The spiropyran‐crosslinked elastomer features both force and UV light‐induced color changes originating from the structural transformation from ring‐close spiropyran form to ring‐open merocyanine form of the mechanophores, and excellent mechanical properties (favorable elasticity of 480 kPa, large stretchability of 3400% strain, and high toughness of 8.4 kJ m −1 ) benefiting from the energy dissipation by breakage of sacrificial bonds. In particular, it is demonstrated that the multi‐mechanoresponsive and mechanically strong elastomer can be served as a conceptual sensor to quantify mechanical stretchability by a visible color change. This work shows promising potential for mechanochemical sensing applications.