Sodium alginate (SA) was used for the first time to noncovalently functionalize amino-graphene oxide (aGO) to produce the SA-functionalized GO, A-aGO. A-aGO was then filled into a double-network (DN) hydrogel consisting of an alginate network (SA) and a polyacrylamide (PAAm) network. Before UV curing, A-aGO was able to provide the SA/PAAm DN hydrogel with a remarkable thixotropic property, which is desirable for 3D printing. Thus, the A-aGO-filled DN hydrogel could be nicely used as an “ink” of a 3D printer to print complicated 3D structures with a high stackability and high shape fidelity. After UV curing, the 3D-printed A-aGO filled DN hydrogel showed robust mechanical strength and great toughness. For the function of A-aGO it was considered that A-aGO acted as a secondary but physical cross-linker, not only to give the hydrogel a satisfactory thixotropic property but also to increase the energy dissipation by combining the physical SA network and the chemical PAAm network. As an exciting result we successfully developed a 3D printable and mechanically robust hydrogel.

中文翻译：

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基于藻酸盐和氧化石墨烯的3D可打印且机械坚固的水凝胶

首次使用海藻酸钠（SA）对氨基石墨烯氧化物（aGO）进行非共价官能化，以生产SA官能化的GO，A-aGO。然后将A-aGO填充到由藻酸盐网络（SA）和聚丙烯酰胺（PAAm）网络组成的双网络（DN）水凝胶中。在UV固化之前，A-aGO能够提供具有显着触变性的SA / PAAm DN水凝胶，这是3D打印所希望的。因此，填充A-aGO的DN水凝胶可以很好地用作3D打印机的“墨水”，以高堆叠性和高形状保真度打印复杂的3D结构。UV固化后，3D打印的填充A-aGO的DN水凝胶显示出强大的机械强度和极大的韧性。对于A-aGO的功能，人们认为A-aGO充当了次级但物理的交联剂，不仅可以使水凝胶具有令人满意的触变性，而且可以通过结合物理SA网络和化学PAAm网络来增加能量消散。令人兴奋的结果是，我们成功开发了3D可打印且机械坚固的水凝胶。