writer：Baoyuan Zhang, Zijian Gao, Guanghui Gao, Wei Zhao, Jiasheng Li, Xiuyan Ren*
keywords：Highly mechanical and fatigue resistant double network hydrogels
source：期刊
specific source：Macromolecular Materials and Engineering
Issue time：2018年

Double network (DN) hydrogels with high strength and toughness are considered as promising soft materials. Herein, we explored a dual physically cross-linked HPAAm/Alginate-Ca2+ DN hydrogel, consisting of hydrophobic association polyacrylamide (HPAAm) network and Ca2+ cross-linked alginate network. The HPAAm/Alginate-Ca2+ DN hydrogel exhibits excellent mechanical properties with the fracture stress of 1.16 MPa (3.0 and 1.7 times higher than that of HPAAm hydrogel and HPAAm/Alginate hydrogel, respectively), fracture strain of 2604%, elastic modulus of 71.79 kPa, and toughness of 14.20 MJ m-3. HPAAm/Alginate-Ca2+ DN hydrogels also demonstrate self-recovery, notch-insensitivity and fatigue resistance properties without any external stimuli at room temperature through reversible physical bonds consisting of hydrophobic association and ionic crosslinking. As a result, the dual physical crosslinking would offer an avenue to design DN hydrogels with desirable properties for broadening current applications of soft materials.