Carbon Dots Intensified Mechanochemiluminescence from Waterborne Polyurethanes as Tunable Force Sensing Materials

1,2-Dioxetane is a well-known chemiluminescent mechanophore allowing real-time monitoring of polymer chain scission, but usually suffers from fluorescence quenching in polar environments. Herein, a series of mechanochemiluminescent waterborne polyurethanes/carbon dots composites ( WPU-CDs ) have been synthesized by incorporating fluorescent CD s to promote the energy transfer process in different environments. The resulting bulk WPU s, and in particular, their swollen films filled with a large amount of polar solvents (water and ionic liquid) emit intense mechanochemiluminescence. Thus force-induced covalent bond scission and stress distribution within these different WPU-CDs films can be sensitively visualized. Furthermore, the ionic liquid containing films exhibited both electrical and luminescent signal changes under stretching, which offer a new kind of force sensor responsive at a broad detecting strain range and for multi-mode strain analysis. This study is expected to stimulate new research endeavors in mechanistic insight on waterborne polyurethanes and the corresponding stretchable sensing devices.