Synthesis of Mechanoresponsive Polyolefins via ADMET Polymerization: Enhancing Mechanophore Activation through Backbone Hydrogenation.

Polyolefins represent an important class of synthetic polymers, yet their functionalization remains challenging due to their nonpolar backbones. While mechanophores offer a promising strategy for introducing mechanoresponsive functionality, current approaches predominantly rely on complex multicyclic monomers and are largely limited to force-induced degradation. Herein, we report a facile strategy to synthesize mechanofluorescent polyolefins via acyclic diene metathesis (ADMET) using an anthracene-maleimide adduct as a readily accessible mechanophore. Copolymerization with 1,10-undecadiene afforded polyolefins that exhibited mechanofluorescent behavior upon ultrasonication, ball milling, and compression. Notably, hydrogenation of the unsaturated backbone yielded a semicrystalline polyethylene with significantly enhanced mechanophore activation efficiency under compression. DSC and WAXS analysis revealed that this enhancement originates from increased crystallinity and restricted segmental motion, which suppress energy dissipation and channel mechanical force more efficiently toward mechanophore activation. This work establishes ADMET as a promising strategy for constructing mechanoresponsive polyolefins and reveals a lever effect in which physical ordering governs mechanochemical activation in bulk.