Shape-memory hydrogels are expected to be used not only in an ordinary environment, but also in some special environments, such as under ultraviolet (UV) irradiation. Developing novel shape-memory polyvinyl alcohol (PVA)/tea polyphenol (TP) hydrogels with UV shielding performance is realistically important in application fields. Herein, we designed functional PVA/TP hydrogels with excellent UV-shielding ability and improved the shape memory on hot water stimuli. This study shows that the abundant hydrogen bonds between PVA and TP are the source of shape memory. The PVA hydrogels with 8 wt% TP loading could approximately recover their original shape after deformation when immersed in water at 50 °C for 30 s. Meanwhile, the hydrogels also had excellent UV shielding capacity. After ageing under UV for 16 days, the observed shape of the hydrogel with 8 wt% TP loading retained 74.7% of the original, and the hydrogel could effectively protect the skin of mice from damage under 10 mW cm⁻² UV irradiation. With the understanding of the UV-shielding behavior of hydrogels, this study has been able to generate biomedical materials for human skin protection, specifically skin covering the joint areas, where shape memory of the applied materials is essential.

中文翻译：

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引入茶多酚制备具有优异形状记忆和紫外线屏蔽性能的聚乙烯醇水凝胶

形状记忆水凝胶预计不仅可用于普通环境，还可用于一些特殊环境，例如紫外线（UV）照射下。开发具有紫外线屏蔽性能的新型形状记忆聚乙烯醇（PVA）/茶多酚（TP）水凝胶在应用领域具有现实意义。在此，我们设计了具有优异紫外线屏蔽能力的功能性PVA/TP水凝胶，并提高了对热水刺激的形状记忆。这项研究表明，PVA 和 TP 之间丰富的氢键是形状记忆的来源。TP负载量为8 wt%的PVA水凝胶在50 ℃水中浸泡30 s后变形后可大致恢复其原始形状。同时，水凝胶还具有优异的紫外线屏蔽能力。在紫外线下老化16天后，观察到的具有8wt％TP负载的水凝胶的形状保留了原始的74.7％，并且该水凝胶可以有效保护小鼠皮肤免受10mW cm -2 紫外线照射下的^损伤。通过了解水凝胶的紫外线屏蔽行为，这项研究已经能够生产出用于人类皮肤保护的生物医学材料，特别是覆盖关节区域的皮肤，其中所应用材料的形状记忆至关重要。