The utility and lifetime of materials made from polymer networks, including hydrogels, depend on their capacity to stretch and resist tearing. In gels and elastomers, those mechanical properties are often limited by the covalent chemical structure of the polymer strands between cross-links, which is typically fixed during the material synthesis. We report polymer networks in which the constituent strands lengthen through force-coupled reactions that are triggered as the strands reach their nominal breaking point. In comparison with networks made from analogous control strands, reactive strand extensions of up to 40% lead to hydrogels that stretch 40 to 50% further and exhibit tear energies that are twice as large. The enhancements are synergistic with those provided by double-network architectures and complement other existing toughening strategies.

中文翻译：

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通过拉长聚合物链的力触发化学反应增韧水凝胶

由聚合物网络制成的材料（包括水凝胶）的实用性和使用寿命取决于它们的拉伸和抗撕裂能力。在凝胶和弹性体中，这些机械性能通常受到交联之间聚合物链的共价化学结构的限制，该结构通常在材料合成过程中固定。我们报告了聚合物网络，其中组成链通过力耦合反应延长，当链达到其标称断裂点时触发该反应。与由类似控制链制成的网络相比，高达 40% 的反应链延伸导致水凝胶进一步拉伸 40% 至 50%，并表现出两倍大的撕裂能量。