Zwitterionic hydrogels have attracted tremendous interest due to their densely charged network, ultralow fouling characteristics, and excellent biocompatibility. However, the unsatisfactory mechanical performance of the zwitterionic gels limits their practical applications. Here, we developed a new class of zwitterionic hydrogels from a structurally ameliorated sulfobetaine monomer, 3-(1-(4-vinylbenzyl)-1H-imidazol-3-ium-3-yl)propane-1-sulfonate (VBIPS). The incorporated benzene and imidazole greatly enhance the tensile toughness and fracture toughness of the gel, which are 40 and 60 times higher than those of the conventional zwitterionic hydrogel, respectively. An obvious crack blunting occurs during the crack extension. In situ microscopic observation reveals that the outstanding toughness originates from the formation of a two-phase structure at room temperature, with an obvious contrast of the association energy. The mechanical properties of the gel can be well-tuned by changing the pH, and self-healing is achieved with an acid treatment. The VBIPS gel also possesses excellent short-term antifouling properties and the attached bacteria in a longer timescale can be easily released via salt treatment. To expand the application potentials, a VBIPS ionogel is prepared by soaking the gel in ionic liquids, which is flexible, antifreezing, and can be used as a strain sensor. This work provides a molecular strategy to toughen zwitterionic hydrogels, which should broaden their applications in diverse fields.

中文翻译：

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用于软电子应用的具有高韧性和自愈能力的分子工程两性离子水凝胶

两性离子水凝胶由于其密集的带电网络、超低污染特性和优异的生物相容性而引起了极大的兴趣。然而，两性离子凝胶不令人满意的机械性能限制了它们的实际应用。在这里，我们从结构改善的磺基甜菜碱单体 3-(1-(4-vinylbenzyl)-1 H开发了一类新的两性离子水凝胶-咪唑-3-鎓-3-基）丙烷-1-磺酸盐（VBIPS）。掺入的苯和咪唑大大提高了凝胶的拉伸韧性和断裂韧性，分别比传统的两性离子水凝胶提高了 40 倍和 60 倍。裂纹扩展过程中出现明显的裂纹钝化现象。原位显微观察表明，优异的韧性源于室温下两相结构的形成，缔合能对比明显。凝胶的机械性能可以通过改变 pH 值来调整，并通过酸处理实现自修复。VBIPS 凝胶还具有出色的短期防污性能，在较长时间范围内附着的细菌可以通过盐处理轻松释放。为扩大应用潜力，VBIPS ionogel 是通过将凝胶浸泡在离子液体中制备的，它具有柔韧性、抗冻性，可用作应变传感器。这项工作提供了一种增韧两性离子水凝胶的分子策略，这将扩大其在不同领域的应用。