Conventional chemically cross-linked double network hydrogels (DN hydrogels) are considered as one of the toughest soft materials. However, they lack self-healing properties due to their non-reversible covalent bonds. In this work, we propose a new design strategy to synthesize a dual ionic cross-linked polyethylene glycol (PEG)/poly(acrylamide-co-acrylic acid) (PAMAA) DN hydrogels, consisting of an ionic cross-linked linear chain extension of PEG and a PAMAA-Fe³⁺ as the first and second physical networks, respectively. Due to the reversible non-covalent bonds in both networks (Fe³⁺ coordination interactions and hydrogen bonds), the DN hydrogels can achieve high mechanical properties (σ_f of ∼0.36 MPa and strain of ∼1350%) and complete self-healing ability within 12 h. Moreover, due to the free ions diffusion in the water medium of the DN hydrogels, the as-prepared hydrogels also exhibited electrical conductivity and stretch sensitivity. Our results offer a new design strategy to improve the strength and self-healing ability of DN hydrogels by introducing a dual ionic cross-linking within the network, which we hope will provide an alternative focus for the design of tough and self-healing hydrogels with desirable properties.

常规的化学交联的双网络水凝胶（DN水凝胶）被认为是最坚韧的软质材料之一。但是，由于它们不可逆的共价键，它们缺乏自我修复的特性。在这项工作中，我们提出了一种新的设计策略来合成双离子交联的聚乙二醇（PEG）/聚（丙烯酰胺-丙烯酸）（PAMAA）DN水凝胶，其中包括PEG和PAMAA-Fe ^3+分别作为第一和第二物理网络。由于在两个网络中的可逆的非共价键（铁³⁺协调相互作用和氢键），所述DN水凝胶可以实现高的机械性能（σ _˚F约0.36 MPa的应变和约1350％的应变），并在12 h内具有完全的自愈能力。此外，由于自由离子在DN水凝胶的水介质中的扩散，因此制备的水凝胶还显示出导电性和拉伸敏感性。我们的结果提供了一种新的设计策略，通过在网络内引入双离子交联来提高DN水凝胶的强度和自修复能力，我们希望这将为设计具有韧性的自修复水凝胶提供另一种重点。理想的特性。