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

详细信息    查看全文

• 作者：Yang Hu ; Zhengshan Du ; Xiaolan Deng ; Tao Wang ; Zhuohong Yang ; Wuyi Zhou ; Chaoyang Wang
• 刊名：Macromolecules
• 出版年：2016
• 出版时间：August 9, 2016
• 年：2016
• 卷：49
• 期：15
• 页码：5660-5668
• 全文大小：603K
• 年卷期：0
• ISSN：1520-5835

文摘

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.