Force-dependent color generation using a multifunctional mechanophore

Stimuli-responsive polymers that provide a unique response that is coupled to a variable external input create opportunities for realizing non-binary multifunctional materials. Mechanochem. responsive polymers are an excellent platform for achieving novel materials innovations and exploring fundamental mechanisms of force-coupled reactivity, informing the next generation of mechanophore design. Mechanochromic polymers have been designed for visual stress reporting and damage detection; however, previously developed materials are limited to a single color transition that qual. signals the existence or absence of stress without the ability to differentiate between applied external forces of different magnitudes. Here, we report a mechanophore capable of multiple force-activated transformations resulting in distinct color states at different applied forces. The demonstration of force-correlated mechanochromism is an important step toward the development of advanced, quant. remote sensing strategies to evaluate the status of polymeric materials in demanding applications