Mechanically strong and tough hydrogels with pH-triggered self-healing and shape memory properties based on a dual physically crosslinked network

• Published in: Polymer chemistry Vol. 11; no. 11; pp. 196 - 1918
• Main Authors: Liu, Tao, Zou, Shaoshuang, Hang, Chen, Li, Jian, Di, Xiang, Li, Xiaohui, Wu, Qiang, Wang, Fenfen, Sun, Pingchuan
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 21.03.2020
• Subjects: Biomedical materials; Bond strength; Bonding strength; Crosslinking; Dimers; Elongated structure; Energy dissipation; Hydrogels; Hydrogen bonding; Mechanical properties; Modulus of elasticity; Polymer chemistry; Recovery; Shape memory; Synergistic effect; Tensile strength; Toughness
• ISSN: 1759-9954; 1759-9962
• DOI: 10.1039/c9py01862j

Physically crosslinked hydrogels with a reversible nature have attracted much attention in recent decades due to their fascinating self-recovery and self-healing properties, but the low mechanical strength hinders their development for many stress-bearing applications. In this study, inspired by the multiple supramolecular interactions in nature including hydrogen bonding and ionic bonds, we proposed a simple strategy to fabricate high-performance dual physically crosslinked D-hydrogels, which is triggered by the self-complementary quadruple hydrogen bonding interactions between 2-ureido-4[1 H ]-pyrimidinone (UPy) dimers and Fe 3+ ionic coordination bonds as the dynamic sacrificial crosslinkers, thus obviously enhancing the mechanical strength and toughness. Due to the synergistic effect of the two types of physical crosslinking interactions, the D-hydrogels exhibit outstanding mechanical properties, such as a tensile strength of 7.9 MPa, an elastic modulus of 6.9 MPa, and an elongation at break of 541%, with an optimized structure. Furthermore, these reversible dual physical crosslinks enable the D-hydrogels to efficiently dissipate energy with a high toughness (up to 29 MJ m −3 ) while imparting good self-recovery properties, a pH-triggered healing capability and pH-responsive shape memory to the network. This dual physically crosslinked hydrogel with excellent mechanical performance as well as good recovery and self-healing properties will hopefully be exploited as a promising candidate for various biomedical applications. A kind of dual physically crosslinked hydrogel with pH-triggered self-healing and shape memory properties is reported.