The development of easy and cost-effective strategies for making multifunctional hydrogels is of great scientific interest. Here, a chitosan/polyvinyl alcohol/tannic acid (CS/PVA/TA) composite hydrogel was prepared by a simple method of γ-ray-induced crosslinking and immersion in TA solution. The chemical composition, transparency, microstructure, mechanical properties and antibacterial activity of the obtained composite hydrogel were characterized by Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy, scanning electron microscopy (SEM), tensile measurement, and antibacterial test, respectively. The immersion in TA not only provided a CS (M_w 20,000 g.mol⁻¹)/PVA composite hydrogel with improved mechanical performance, i.e., tensile strength and elongation-at-break increased by 1100 and 487%, respectively, but also it preserved high transparency of the pure irradiated PVA hydrogel (transmittance exceeded 50% at 660 nm). In addition, the composite hydrogel possessed good antibacterial activity against gram-negative and gram-positive bacteria. The rationality of the immersion TA method in principle was proved by the hydrogen bond simulation. This work provides a simple method for the preparation of multifunctional hydrogels, suitable for large-scale production, and is expected to promote their application in the fields of biomedicine and wound dressings.

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中文翻译：

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壳聚糖/聚乙烯醇/鞣酸多网络复合水凝胶的制备与表征

开发用于制造多功能水凝胶的简单且具有成本效益的策略具有重大的科学意义。在这里，通过γ射线诱导交联和浸入TA溶液的简单方法制备壳聚糖/聚乙烯醇/单宁酸（CS/PVA/TA）复合水凝胶。所得复合水凝胶的化学成分、透明度、微观结构、力学性能和抗菌活性分别通过傅里叶变换红外光谱（FTIR）、紫外-可见光谱、扫描电子显微镜（SEM）、拉伸测量和抗菌试验进行表征。浸入 TA 不仅提供了 CS ( M _w 20,000 g.mol ^-1)/PVA 复合水凝胶的力学性能得到改善，即拉伸强度和断裂伸长率分别提高了 1100% 和 487%，但同时保持了纯辐照 PVA 水凝胶的高透明度（660 nm 下的透光率超过 50%） . 此外，复合水凝胶对革兰氏阴性菌和革兰氏阳性菌具有良好的抗菌活性。氢键模拟从原理上证明了浸入式TA方法的合理性。该工作为多功能水凝胶的制备提供了一种简单的方法，适合大规模生产，有望促进其在生物医学和伤口敷料领域的应用。

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