Anisotropically Fatigue-Resistant Hydrogels

Nature builds biological materials from limited ingredients, however, with unparalleled mechanical performances compared to artificial materials, by harnessing inherent structures across multi-length-scales. In contrast, synthetic material design overwhelmingly focuses on developing new compounds, and fails to reproduce the mechanical properties of natural counterparts, such as fatigue resistance. Here, a simple yet general strategy to engineer conventional hydrogels with a more than 100-fold increase in fatigue thresholds is reported. This strategy is proven to be universally applicable to various species of hydrogel materials, including polysaccharides (i.e., alginate, cellulose), proteins (i.e., gelatin), synthetic polymers (i.e., poly(vinyl alcohol)s), as well as corresponding polymer composites. These fatigue-resistant hydrogels exhibit a record-high fatigue threshold over most synthetic soft materials, making them low-cost, high-performance, and durable alternatives to soft materials used in those circumstances including robotics, artificial muscles, etc.

Automated summary

Nature utilizes inherent structures across multiple length-scales to build biological materials with exceptional mechanical performances, surpassing artificial materials. A simple and universal strategy has been developed to significantly increase the fatigue thresholds of conventional hydrogels, making them durable alternatives to most synthetic soft materials. These fatigue-resistant hydrogels show high-performance and cost-effective features, suitable for various applications such as robotics and artificial muscles.