Mechanochemistry for On-Demand Polymer Network Materials

Contemporary polymer network materials, such as hydrogels and elastomers, require not only enhanced mechanical properties but also adaptability during or after use. Polymer mechanochemistry, which utilizes mechanical force to induce chemical reactions within polymers, has shown great potential in meeting these demands. This Perspective will explore how mechanophores, when integrated into polymer networks, can regulate microscale fracture pathways, either strengthening or weakening the materials. Additionally, it will examine how force-induced bond scission can trigger additional chemical reactions to adaptively adjust the polymer structures for on-demand functions. These force-activated chemical reactions could lead to strategies for strengthening, reshaping, and patterning materials through polymer growth, or, conversely, result in extensive bond scission and material degradation. The Perspective will also highlight the great potential of tough double network hydrogels as mechanochemical materials that can use mechanical energy to drive chemical reactions in an efficient and controllable manner. This opens up new possibilities for developing force-triggered "living materials" similar to biological systems.