Self-Strengthening Tough Elastomers Enabled by Dynamic Bottlebrush Mechanophores

Low activation efficiency of mechanosensitive groups in bulk materials challenges the expansion of practical applications of mechanochemistry. Here, we wish to report a topological approach to address this problem. Assembling dynamic mechanophores in a bottlebrush topology can increase the scission probability and unlock multiple rounds of activation. This concept is materialized via a new ring-opening polymerization reaction of cyclic carbonates followed by cross-linking with thermoplastic polyurethanes. The resulting elastomers, featuring advanced topology at the cross-linking points, display enhanced mechanosensitivity, high mechanical performance, and training-induced self-strengthening behavior without chemical amplification with a second component.