Shape-memory actuators allow machines ranging from robots to medical implants to hold their form without continuous power, a feature especially advantageous for situations where these devices are untethered and power is limited. Although previous work has demonstrated shape-memory actuators using polymers, alloys, and ceramics, the need for micrometer-scale electro–shape-memory actuators remains largely unmet, especially ones that can be driven by standard electronics (~1 volt). Here, we report on a new class of fast, high-curvature, low-voltage, reconfigurable, micrometer-scale shape-memory actuators. They function by the electrochemical oxidation/reduction of a platinum surface, creating a strain in the oxidized layer that causes bending. They bend to the smallest radius of curvature of any electrically controlled microactuator (~500 nanometers), are fast (<100-millisecond operation), and operate inside the electrochemical window of water, avoiding bubble generation associated with oxygen evolution. We demonstrate that these shape-memory actuators can be used to create basic electrically reconfigurable microscale robot elements including actuating surfaces, origami-based three-dimensional shapes, morphing metamaterials, and mechanical memory elements. Our shape-memory actuators have the potential to enable the realization of adaptive microscale structures, bio-implantable devices, and microscopic robots.

形状记忆执行器允许从机器人到医疗植入物的机器在没有持续供电的情况下保持其形状，这一特性对于这些设备不受限制且功率有限的情况尤其有利。虽然之前的工作已经证明了使用聚合物、合金和陶瓷的形状记忆执行器，但对微米级电子形状记忆执行器的需求仍然很大程度上没有得到满足，尤其是那些可以由标准电子设备（~1 伏特）驱动的执行器。在这里，我们报告了一类新的快速、高曲率、低电压、可重构、微米级形状记忆执行器。它们通过铂表面的电化学氧化/还原起作用，在氧化层中产生导致弯曲的应变。它们弯曲到任何电控微致动器的最小曲率半径（~500 纳米），速度快（<100 毫秒运行），并在水的电化学窗口内运行，避免与析氧相关的气泡产生。我们证明这些形状记忆致动器可用于创建基本的电可重构微型机器人元件，包括致动表面、基于折纸的三维形状、变形超材料和机械记忆元件。我们的形状记忆执行器有可能实现自适应微型结构、生物可植入设备和微型机器人。我们证明这些形状记忆致动器可用于创建基本的电可重构微型机器人元件，包括致动表面、基于折纸的三维形状、变形超材料和机械记忆元件。我们的形状记忆执行器有可能实现自适应微型结构、生物可植入设备和微型机器人。我们证明这些形状记忆致动器可用于创建基本的电可重构微型机器人元件，包括致动表面、基于折纸的三维形状、变形超材料和机械记忆元件。我们的形状记忆执行器有可能实现自适应微型结构、生物可植入设备和微型机器人。