Hydrogels are ideal lubricants due to their hydrophilicity and ability to mitigate issues such as creep and leakage. Based on the diversity of application environments, it is crucial to develop hydrogels with adjustable lubrication that can adjust their lubrication properties by changing in the external environment. However, they still face challenges in balancing responsiveness, lubrication efficacy, and safety. This study presents a pH-responsive hydrogel prepared from polyvinylpyrrolidone and phytic acid, with the addition of MXene and glycerol to enhance its tribological performance. The optimal contents of MXene and glycerol for peak lubrication efficiency are found to be 5 mg/mL and 5 wt %, respectively. This hydrogel lubricant can maintain a low-friction state without failure in long-term testing for 3 h, achieving a coefficient of friction (COF) of 0.01. The synergistic lubrication effect of MXene and glycerol reached a friction reduction of 69% and a wear resistance improvement of up to 96%. Moreover, the COF can be regulated by adjusting the pH value. This hydrogel also stands out with its robust self-healing, injectability, and biocompatibility, making it an excellent candidate for advanced lubrication in biomedical applications.

中文翻译：

---

可注射和自修复的 MXene 增强 pH 响应水凝胶：实现低摩擦和持久润滑


水凝胶是理想的润滑剂，因为它们具有亲水性，并且能够缓解蠕变和泄漏等问题。基于应用环境的多样性，开发具有可调节润滑功能的水凝胶至关重要，该水凝胶可以通过改变外部环境来调整其润滑性能。然而，他们在平衡响应性、润滑效率和安全性方面仍然面临挑战。本研究介绍了一种由聚乙烯吡咯烷酮和植酸制备的 pH 响应性水凝胶，并添加了 MXene 和甘油以增强其摩擦学性能。发现 MXene 和甘油的最佳含量分别为 5 mg/mL 和 5 wt %。这种水凝胶润滑剂可以在 3 h 的长期测试中保持低摩擦状态而不会失效，摩擦系数 （COF） 达到 0.01。MXene 和甘油的协同润滑效果达到了 69% 的摩擦减少和高达 96% 的耐磨性改善。此外，可以通过调整 pH 值来调节 COF。这种水凝胶还以其强大的自修复性、可注射性和生物相容性而著称，使其成为生物医学应用中高级润滑的绝佳候选者。