Highly Sensitive Built‐In Strain Sensors for Polymer Composites: Fluorescence Turn‐On Response through Mechanochemical Activation

A new class of rationally designed mechanophores is developed for highly sensitive built-in strain sensors in polymer composites. These mechanophores are designed to regenerate the π-conjugation pathway between the electron donor and electron acceptor by force-induced cleavage of the covalent bond to form a fluorescent dipolar dye.