We report the ultrastiff and tough poly(acrylamide-co-acrylic acid)/Na-alginate/Fe³⁺ (P(AM-co-AA)/Na-alginate/Fe³⁺) hydrogel via the formation of hybrid ionic–hydrogen bond cross-linking networks. The optimal P(AM-co-AA)/Na-alginate/Fe³⁺ hydrogel possessed super high elastic modulus (∼24.6 MPa), tensile strength (∼10.4 MPa), compression strength (∼44 MPa), and toughness (∼4800 J/m²). The P(AM-co-AA)/Na-alginate/Fe³⁺ hydrogel was highly stable and maintained its superior mechanical properties in 0.5–2 M NaCl solution, aqueous solution with pH ranging from 4 to 10. The ionic cross-linking networks of the P(AM-co-AA)/Na-alginate/Fe³⁺ hydrogels can be locally and selectively dissociated by treating with aqueous NaOH solution with pH of 13 for 1 min and reformed by locally adding the additional Fe³⁺ solutions, making the hydrogels healable and cohesive. The healed hydrogels from the cutting surfaces can bear a tensile strength of up to 7.1 MPa. Various complex hydrogel structures can be constructed by using the P(AM-co-AA)/Na-alginate/Fe³⁺ hydrogels as building blocks via the adhesion of as-prepared hydrogels.

中文翻译：

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超硬，强韧且可修复的离子氢键交联水凝胶及其作为构建复杂水凝胶结构的基础材料的用途

我们通过杂化离子-氢的形成报告了超硬而坚韧的聚（丙烯酰胺-共丙烯酸）/藻酸钠/ Fe ³⁺（P（AM- co - AA ）/藻酸钠/ Fe ³⁺）水凝胶键交联网络。最佳的P（AM- co -AA）/藻酸钠/ Fe ³⁺水凝胶具有超高的弹性模量（〜24.6 MPa），抗张强度（〜10.4 MPa），抗压强度（〜44 MPa）和韧性（〜 4800 J / m ²）。P（AM- co -AA）/海藻酸钠/ Fe ³⁺水凝胶在0.5–2 M NaCl溶液，pH范围为4至10的水溶液中保持高度稳定性并保持其优异的机械性能。P（AM- co -AA）/ Na-藻酸盐/ Fe的离子交联网络³⁺水凝胶可通过用pH为13的NaOH水溶液处理1分钟而局部解离，并通过局部添加其他Fe ³⁺溶液进行重整，从而使水凝胶可修复且具有粘性。来自切割表面的已修复水凝胶可承受高达7.1 MPa的拉伸强度。通过将P（AM- co -AA）/藻酸钠/ Fe ³⁺水凝胶用作构建块，可以通过制备水凝胶的粘附来构建各种复杂的水凝胶结构。