Cao Zhenxing, Yuan Zhaoyang, Wu Rui, Wu Haitao, Jin Biqiang, Zheng Jing, Wu Jinrong
State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China.
Gels. 2021 Oct 21;7(4):177. doi: 10.3390/gels7040177.
Many high-strength hydrogels have been developed in recent years; however, few of them are both tough and resilient, and their intrinsic paradoxical nature makes designing a gel with both high toughness and high resilience a great challenge. To address this problem, we introduced both N,N,N,N-pentamethyldiethylenetriamine (PA) and N,N-methylenebisacrylamide (MBA) into polyacrylamide hydrogel networks to construct an entangled network that contains chemically cross-linked chains and branched chains simultaneously. The entanglements of branched chains can act as a physical cross-linking point to uniformly disperse stress on molecular chains, and chemical cross-linking ensures the stability of the hydrogel network. The increase in the number and length of branched chains is able to achieve an enhancement in strength while the slip of the entangled polymer chains can effectively achieve energy dissipation and can improve the toughness of the gel. Moreover, the resultant hydrogels exhibit an excellent resilience (>98%). Therefore, high toughness and resilience are achieved simultaneously. In addition, we also investigated the initiation mechanism of PA. This strategy creates a new way for the preparation of next-generation high toughness and high resilience hydrogel-based materials, which have promising applications in wearable, flexible strain/pressure sensors.
近年来，人们开发了许多高强度水凝胶；然而，其中很少有兼具高韧性和高弹性的，其固有的矛盾性质使得设计一种同时具有高韧性和高弹性的凝胶成为一项巨大挑战。为了解决这个问题，我们将N,N,N,N-五甲基二亚乙基三胺（PA）和N,N-亚甲基双丙烯酰胺（MBA）引入聚丙烯酰胺水凝胶网络中，构建了一个同时包含化学交联链和支链的缠结网络。支链的缠结可以作为物理交联点，使应力均匀分散在分子链上，而化学交联则确保了水凝胶网络的稳定性。支链数量和长度的增加能够实现强度的提高，而缠结聚合物链的滑移可以有效地实现能量耗散，并提高凝胶的韧性。此外，所得水凝胶表现出优异的弹性（>98%）。因此，同时实现了高韧性和高弹性。此外，我们还研究了PA的引发机制。该策略为制备下一代高韧性和高弹性水凝胶基材料创造了一种新方法，这些材料在可穿戴、柔性应变/压力传感器方面具有广阔的应用前景。
