1. College of Materials and Energy, South China Agricultural University, Guangzhou, China;2. Research Institute of Materials Science, South China University of Technology, Guangzhou, China;3. College of Food Science and Technology, Huazhong Agricultural University, Wuhan, China
Abstract:
In this study, the authors report a novel class of super tough nanocomposite hydrogels with physically dual‐crosslinking effects (DC hydrogels) through introducing strong ionic coordination interactions. Herein, graphene oxide (GO) nanosheets and iron (Fe3+) ions act as physical cross‐linkers. GO nanosheets trigger the formation of the first cross‐linking points through hydrogen bonding with poly(acrylamide‐co‐acrylic acid) (p(AAm‐co‐AAc)) chains, while the second cross‐linking points are formed by strong ionic coordination interactions between Fe3+ ions and ? COO? groups of p(AAm‐co‐AAc) chains. The optimal tough DC hydrogel displays superstretchability (≈20.8 times), remarkable tensile strength (≈3.7 MPa), high toughness (≈48.71 MJ m?3), good self‐recovery property (≈84.1% toughness recovery within 4 h without any external stimuli) and fatigue resistance. In summary, this study opens up a new avenue to design and fabricate highly tough hydrogels with outstanding comprehensive properties by the synergistic effects of nanocomposite and dual‐crosslinked hydrogels.
