Hydrogels are an exciting class of materials for new and emerging robotics. For example, actuators based on hydrogels have impressive deformability and responsiveness. Studies into hydrogels with autonomous locomotive abilities, however, are limited. Existing hydrogels achieve locomotion through the application of cyclical stimuli or chemical modifications. Here, we report the fabrication of active hydrogels with an intrinsic ability to move on the surface of water without operated stimuli for up to 3.5 hours. The active hydrogels were composed of hydrophobic and hydrophilic groups and underwent a dynamic wetting process to achieve spatial and temporal control of surface tension asymmetry. Using surface tension, the homogeneous active hydrogels propelled themselves and showed controlled locomotion on water, similar to common water striders.

水凝胶是用于新兴机器人技术的一类令人兴奋的材料。例如，基于水凝胶的执行器具有令人印象深刻的变形能力和响应能力。然而，对具有自主运动能力的水凝胶的研究是有限的。现有的水凝胶通过应用循环刺激或化学修饰来实现运动。在这里，我们报告了活性水凝胶的制造，该水凝胶具有在没有操作刺激的情况下在水面上移动长达 3.5 小时的内在能力。活性水凝胶由疏水基团和亲水基团组成，并经过动态润湿过程以实现表面张力不对称的空间和时间控制。使用表面张力，均质的活性水凝胶可以推动自身并在水上表现出受控的运动，类似于普通的水黾。