Illeperuma, WidushaSun, Jeong-YunSuo, ZhigangVlassak, Joost2015-02-042014Illeperuma, Widusha R.K., Jeong-Yun Sun, Zhigang Suo, and Joost J. Vlassak. 2014. “Fiber-Reinforced Tough Hydrogels.” Extreme Mechanics Letters (November). doi:10.1016/j.eml.2014.11.001.2352-4316http://nrs.harvard.edu/urn-3:HUL.InstRepos:13919163Using strong fibers to reinforce a hydrogel is highly desirable but difficult. Such a composite would combine the attributes of a solid that provides strength and a liquid that transports matter. Most hydrogels, however, are brittle, allowing the fibers to cut through the hydrogel when the composite is loaded. Here we circumvent this problem by using a recently developed tough hydrogel. We fabricate a composite using an alginate-polyacrylamide hydrogel reinforced with a random network of stainless steel fibers. Because the hydrogel is tough, the composite does not fail by the fibers cutting the hydrogel; instead, it fails by the fibers pulling out of the hydrogel against friction. Both stiffness and strength can be increased significantly by adding fibers to the hydrogel. Before failure the composite dissipates a significant amount of energy, at a tunable level of stress, attaining large deformation. Potential applications of tough hydrogel composites include energy-absorbing helmets, tendon repair surgery, and stretchable biometric sensors.en-USTough hydrogelHydrogel compositeFiber pulloutJournal Article2015-01-25Widusha R. K. Illeperuma, Jeong-Yun Sun, Zhigang Suo and Joost J. Vlassak2015-02-0410.1016/j.eml.2014.11.001