Active metamaterials with shapes or mechanical properties that can be controlled remotely are promising candidates for soft robots, flexible electronics, and medical applications. However, current active metamaterials often have long response times and short ranges of linear working strains. Here, we demonstrate magnetoactive microlattice metamaterials constructed from 3D-printed, ultra-flexible polymer shells filled with magnetorheological (MR) fluid. Under compressive stress, the magnetorheological fluid develops hydrostatic pressure, allowing for a linear compression strain of more than 30% without buckling. We further show that under a relatively low magnetic field strength (approximately 60 mT), the microlattices can become approximately 200% stiffer than those in a relaxed state, and the energy absorption increases ~16 times. Furthermore, our microlattices showed an ultra-low response time with “field on” and “field off” times of ~200 ms and ~50 ms, respectively. The ability to continuously tune the mechanical properties of these materials in real time make it possible to modulate stress‒strain behavior on demand. Our study provides a new route toward large-scale, highly tunable, and remotely controllable metamaterials with potential applications in wearable exoskeletons, tactile sensors, and medical supports.

具有可远程控制的形状或机械性能的活性超材料是软机器人、柔性电子和医疗应用的有前途的候选材料。然而，当前的活性超材料通常具有较长的响应时间和较短的线性工作应变范围。在这里，我们展示了由充满磁流变 (MR) 流体的 3D 打印超柔性聚合物壳构成的磁活性微晶格超材料。在压缩应力下，磁流变流体会产生静水压力，允许超过 30% 的线性压缩应变而不发生屈曲。我们进一步表明，在相对较低的磁场强度（约 60 mT）下，微晶格的硬度比松弛状态下的微晶格强约 200%，并且能量吸收增加约 16 倍。此外，我们的微晶格表现出超低响应时间，“场开启”和“场关闭”时间分别为约 200 毫秒和约 50 毫秒。实时连续调整这些材料的机械性能的能力使得按需调节应力应变行为成为可能。我们的研究为大规模、高度可调和远程可控的超材料提供了一条新途径，在可穿戴外骨骼、触觉传感器和医疗支持方面具有潜在的应用。