Hydrogel actuators, that convert external energy, such as pH, light, heat, magnetic field, and ion strength, into mechanical motion, have been utilized in sensors, artificial muscles, and soft robotics. For a practicality of the hydrogel actuators in a wide range of fields, an establishment of robust mechanical properties and rapid response are required. Several solutions have been proposed, for example, setting porous and anisotropy structures to hydrogels with nanocomposite materials to improve the response speed and deformation efficiency. In this review paper, we focused on hydrogel actuators including various nanocomposite by categorizing the dimensional aspects of additive materials. Moreover, we described the role of diverse additive materials in terms of the improvement of mechanical property and deformation efficiency of the hydrogel actuators. We assumed that this review will provide a beneficial guidance for strategies of developing nanocomposite hydrogel actuators and outlooks for the future research directions.

中文翻译：

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纳米复合水凝胶致动器与各种尺寸的纳米材料杂交，以增强刺激响应性。

将诸如pH值，光，热，磁场和离子强度之类的外部能量转换为机械运动的水凝胶致动器已用于传感器，人造肌肉和软机器人中。为了水凝胶致动器在广泛领域中的实用性，需要建立鲁棒的机械性能和快速响应。已经提出了几种解决方案，例如，使用纳米复合材料在水凝胶中设置多孔和各向异性结构，以提高响应速度和变形效率。在这篇综述文章中，我们通过对添加剂材料的尺寸方面进行分类，重点研究了包括各种纳米复合材料的水凝胶致动器。此外，我们描述了各种添加剂材料在改善水凝胶致动器的机械性能和变形效率方面的作用。我们认为这篇综述将为开发纳米复合水凝胶致动器的策略和未来研究方向的展望提供有益的指导。