Dual Physically Cross-Linked Hydrogels with High Stretchability, Toughness, and Good Self-Recoverability

作者：Hu, Yang; Du, Zhengshan; Deng, Xiaolan; Wang, Tao; Yang, Zhuohong; Zhou, Wuyi^*; Wang, Chaoyang^*

来源：Macromolecules, 2016, 49(15): 5660-5668.

DOI：10.1021/acs.macromol.6b00584

• DOUBLE NETWORK HYDROGELS
• NANOCOMPOSITE HYDROGELS
• MECHANICALLY STRONG
• HYBRID HYDROGELS
• CLAY
• STRENGTH
• LINKING
• ROBUST
• STIFFNESS
• RECOVERY

The applications of hydrogels are severely limited by their weak mechanical properties. Despite recent significant progress in fabricating tough hydrogels, it is still a challenge to realize high stretchability, toughness, and recoverability at the same time in a hydrogel. Herein, we develop a novel class of dual physically cross-linked (DPC) hydrogels, which are triggered by clay nanosheets and iron ions (Fe3+) as cross-linkers. First, clay nanosheets induce the formation of the first cross-linking points through the interaction of hydrogen bonds with poly(acrylamide-co-acrylic acid) (PAm-co-Ac) chains. Then the secondary cross-linking points are introduced by ionic coordinates between Fe3+ and -COO- groups of PAm-co-Ac polymer chains. The mechanical properties of DPC hydrogels can be tuned readily by varying, preparation parameters such as clay concentration, Fe3+ concentration, and molar ratio of Ac/Am. More importantly, the optimal DPC hydrogels possess high tensile strength (ca. 3.5 MPa), large elongation (ca. 21 times), remarkable toughness (ca. 49 MJ m(-3)), and good self-recoverability (ca. 65% toughness recovery within 4 h without any external stimuli). Thus, this work provides a promising strategy for the fabrication of novel tough hydrogel containing a dual physical cross-linked network.

• 出版日期2016-8-9
• 单位华南热带农业大学; 华南农业大学; 华南理工大学