双网络（DN）水凝胶是互穿网络水凝胶的一种特殊情况，由刚性的第一网络和柔性的第二网络构成，两种网络的协同作用使得DN水凝胶具有优良的机械性能。DN水凝胶所具有较高的机械强度、韧性、模量等使得其研究更加广泛，近年来双网络水凝胶取得了很大的研究进展，不仅解决了传统水凝胶脆弱易碎的问题，更扩大了水凝胶的应用范围，且部分DN水凝胶具有自愈性能，在一定程度上延长了水凝胶的使用寿命。该研究比较了DN水凝胶的交联方式（化学交联、物理/化学交联、双重物理交联），归纳了DN水凝胶的形成机制，从动态共价相互作用和非共价作用两方面综述了DN水凝胶的自愈机制，为智能型DN水凝胶的设计及应用提供了思路。

Double network (DN) hydrogel is a special interpenetrating network hydrogel composed of a rigid first network and a flexible second network. The synergy of the two networks makes the DN hydrogel possess excellent mechanical properties. DN hydrogel has higher mechanical strength, toughness and modulus, which makes the research on DN hydrogel more extensive. In recent years, great progress has been made on DN hydrogel, which not only solved the problems related to the fragile and brittle characteristics of traditional hydrogels, but also expanded their application range. In addition, some DN hydrogels have self-healing properties which extend the service life of hydrogels to a certain extent. In this paper, the crosslinking methods of DN hydrogels (chemical crosslinking, physical/chemical crosslinking, dual physical crosslinking) are compared. The formation mechanisms of DN hydrogel are summarized. The self-healing mechanisms of DN hydrogels are reviewed from two aspects, dynamic covalent interaction and non-covalent interaction, which provide ideas for design and application of intelligent DN hydrogels.

国家自然科学基金项目（31871812）；陕西省教育厅专项科研计划项目（19JK0145）；西安市未央区科技计划项目（201942）