Abstract：
Extreme environmental conditions often lead to irreversible structural failure and functional degradation in hydrogels, limiting their service life and applicability. Achieving high toughness, self-healing, and ionic conductivity in cryogenic environments is vital to broaden their applications. Herein, we present a novel approach to simultaneously enhance the toughness, self-healing, and ionic conductivity of hydrogels, via inducing non-freezable water within the zwitterionic cellulose-based hydrogel skeleton. This approach enables resulting hydrogel to achieve an exceptional toughness of 10.8 MJ m-3, rapid self-healing capability (98.9 % in 30 min), and high ionic conductivity (2.9 S m-1), even when subjected to -40 °C, superior to the state-of-the-art hydrogels. Mechanism analyses reveal that a significant amount of non-freezable water with robust electrostatic interactions is formed within zwitterionic cellulose nanofibers-modified polyurethane molecular networks, imparting superior freezing tolerance and versatility to the hydrogel. Importantly, this strategy harnesses the non-freezable water molecular state of the zwitterionic cellulose nanofibers network, eliminating the need for additional antifreeze and organic solvents. Furthermore, the dynamic Zn coordination within these supramolecular molecule chains enhances interfacial interactions, thereby promoting rapid subzero self-healing and exceptional mechanical strength. Demonstrating its potential, this hydrogel can be used in smart laminated materials, such as aircraft windshields.
摘要：
极端的环境条件往往导致水凝胶中不可逆的结构破坏和功能退化。限制其使用寿命和适用性。实现高韧性，自我修复,和低温环境中的离子电导率对于扩大其应用至关重要。在这里，我们提出了一种新颖的方法来同时增强韧性，自我修复,和水凝胶的离子电导率，通过在两性离子纤维素基水凝胶骨架内诱导不可冻结的水。这种方法使所得的水凝胶能够实现10.8MJm-3的特殊韧性，快速自我修复能力（30分钟内98.9％），和高离子电导率(2.9Sm-1)，即使在-40°C下，优于国家的最先进的水凝胶。机理分析表明，两性离子纤维素纳米纤维改性聚氨酯分子网络中形成了大量具有强大静电相互作用的不可冻结水，赋予水凝胶优异的冷冻耐受性和多功能性。重要的是,该策略利用两性离子纤维素纳米纤维网络的不可冻结的水分子状态，消除了额外的防冻剂和有机溶剂的需要。此外，这些超分子分子链中的动态锌配位增强了界面相互作用，从而促进快速零下的自我修复和卓越的机械强度。展示其潜力，这种水凝胶可用于智能层压材料，如飞机挡风玻璃。
