Recently, the use of hybrid double network (DN) hydrogels has become prominent due to their enhanced mechanical properties, which has opened the door for new applications of these soft materials. Only a few of these gels have demonstrated both injectable and moldable capabilities. In this work, we report the mechanical properties, gauge factor (GF) values and demonstrate both the injectability and moldability of a gelatin/polyacrylamide DN hydrogel. We optimized several parameters, such as, gelatin to polyacrylamide ratio, reactant concentrations and metal ion concentration, to produce a gelatin/polyacrylamide hydrogel with superior mechanical properties. The highest water content gel was capable of withstanding strains of 5000% before failure. These gels were facilely injected into molds where they effectively changed shape and maintained similar properties prior to remolding. When 20 mM calcium was doped into a similar gel, a tensile strength of 1.71 MPa was achieved. Aside from improving the mechanical properties of the gels, both Ca2+ and Mg2+ also improved their conductivity, so they were tested for use as strain sensors. The sensitivity of the hydrogel strain sensors were measured using the GF. For the 20 mM Ca2+ hydrogel, these GF values ranged from 1.63 to 6.85 for strains of 100% to 2100% respectively. Additionally, the sensors showed good stability over continuous cyclic stretching, demonstrating their long term reliability for strain sensing.

中文翻译：

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用于敏感和宽范围应变传感应用的可注射和可模压水凝胶

最近，混合双网络 (DN) 水凝胶的使用因其增强的机械性能而变得突出，这为这些软材料的新应用打开了大门。这些凝胶中只有少数具有可注射和可模塑的能力。在这项工作中，我们报告了机械性能、应变系数 (GF) 值并证明了明胶/聚丙烯酰胺 DN 水凝胶的可注射性和可塑性。我们优化了几个参数，例如明胶与聚丙烯酰胺的比例、反应物浓度和金属离子浓度，以生产具有优异机械性能的明胶/聚丙烯酰胺水凝胶。最高含水量的凝胶在失效前能够承受 5000% 的应变。这些凝胶很容易注入模具中，在那里它们有效地改变了形状并在重新成型之前保持了相似的特性。当将 20 mM 钙掺杂到类似的凝胶中时，可达到 1.71 MPa 的拉伸强度。除了提高凝胶的机械性能外，Ca2+ 和 Mg2+ 还提高了它们的导电性，因此它们被测试用作应变传感器。使用 GF 测量水凝胶应变传感器的灵敏度。对于 20 mM Ca2+ 水凝胶，对于 100% 至 2100% 的菌株，这些 GF 值的范围分别为 1.63 至 6.85。此外，传感器在连续循环拉伸中表现出良好的稳定性，证明了它们在应变传感方面的长期可靠性。除了提高凝胶的机械性能外，Ca2+ 和 Mg2+ 还提高了它们的导电性，因此它们被测试用作应变传感器。使用 GF 测量水凝胶应变传感器的灵敏度。对于 20 mM Ca2+ 水凝胶，对于 100% 至 2100% 的菌株，这些 GF 值的范围分别为 1.63 至 6.85。此外，传感器在连续循环拉伸中表现出良好的稳定性，证明了它们在应变传感方面的长期可靠性。除了提高凝胶的机械性能外，Ca2+ 和 Mg2+ 还提高了它们的导电性，因此它们被测试用作应变传感器。使用 GF 测量水凝胶应变传感器的灵敏度。对于 20 mM Ca2+ 水凝胶，对于 100% 至 2100% 的菌株，这些 GF 值的范围分别为 1.63 至 6.85。此外，传感器在连续循环拉伸中表现出良好的稳定性，证明了它们在应变传感方面的长期可靠性。