Hydrogels are crosslinked water-retaining network formed by hydrophilic natural or synthetic polymers. Traditional hydrogels usually are limited by the swelling performance and poor mechanical strength so that not enable to applied in engineering fields. Functional hydrogels possessing tailorable features such as superwettability, strong adhesion, enhanced mechanical strength and conductivity have attracted tremendous interest due to the promising application in functional coating materials, biomedicine, flexible electronics. In this review, the specific design strategies to the corresponding tailorable features of functional hydrogels, such as surface structure construction or chemical modification to obtain the superwettability, are highlighted and classified. Then the applications of functional hydrogels are categorized into three engineering application parts: environment, electronic and biomedicine. More important, the latest advance on the engineering application of functional hydrogels, including oil/water separation, wastewater treatment, flexible electronics, sensor, wound healing and drug delivery, is presented. Finally, the conclusions and potential research prospective in future are proposed.

中文翻译：

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具有大工程应用的小型功能水凝胶

水凝胶是由亲水性天然或合成聚合物形成的交联保水网络。传统的水凝胶通常受到溶胀性能和机械强度差的限制而无法在工程领域中应用。功能性水凝胶具有超润湿性、强附着力、增强的机械强度和导电性等可定制的特性，由于在功能性涂层材料、生物医学、柔性电子等领域的应用前景引起了人们的极大兴趣。在这篇综述中，重点介绍和分类了功能性水凝胶相应可定制特征的具体设计策略，例如表面结构构建或化学修饰以获得超润湿性。然后将功能水凝胶的应用分为三个工程应用部分：环境、电子和生物医学。更重要的是，介绍了功能性水凝胶工程应用的最新进展，包括油水分离、废水处理、柔性电子、传感器、伤口愈合和药物输送。最后提出了结论和未来潜在的研究前景。