Phase-Locked Dynamic and Mechanoresponsive Bonds Design toward Robust and Mechanoluminescent Self-Healing Polyurethanes: A Microscopic View of Self-Healing Behaviors

1,2-Dioxetane is a chemiluminescent mechanophore that allows the study of bond scission events with high sensitivity and resolution. We now make use of this mechanoluminescent probe to give a microscopic view of self-healing behaviors. Herein, a series of robust polyurethanes, with 1,2-dioxetane and aliphatic disulfide incorporated in the main chain and confined in the hard microphase, are developed. Taking advantage of the phase-locked bonds design strategy, these polymers exhibit excellent mechanical properties and self-healing capability as well as sensitive responsiveness to stress. With covalently embedded 1,2-dioxetane, the mechanoluminescent intensity from the healable films is highly dependent on the healing process, which provides a sensitive approach to supervise healing efficiency, particularly at the molecular level. By combining self-healing and self-reporting moieties in one chain, this two-in-one strategy allows for the discrimination of different healing mechanisms, in the aspects of bond formation and chain entanglement, in a visualized way.