Beyond a traditional stimuli-responsive soft actuator that shows a single motion by a stimulus, multidirectional actuation reversal with a single stimulus is highly required in applications such as shape morphing sensors and soft robotics. Liquid crystal elastomers (LCEs) are one of the most attractive candidates for the soft actuator due to their capability of stimuli-responsive shape changing in 3D, which is programmable with local orientation of LC mesogens. Here, a simple but effective method to fabricate monolithic LCE actuators that are capable of reversible curvature reversal in bending and twisting deformation by a single stimulus—heat—is reported. The curvature reversal of the LCE film can be programmed by means of asymmetric crosslinking density along the thickness and the orientation of the LC mesogens. The curvature reversal of the monolithic LCE film exhibits highly reversible (more than 100 times) and fast actuation (≈3–5 s) by heating and cooling, allowing new concept of a practical application using LCE material: a self-regulated smart valve that is capable of qualitatively sorting liquids by temperature. It is believed that this system is potentially applied to a self-regulated sorting platform for various endothermic and exothermic chemical or biological reactions

中文翻译：

---

单片液晶弹性体薄膜的可逆曲率反转及其智能阀应用

除了通过刺激显示单个运动的传统刺激响应软致动器之外，在形状变形传感器和软机器人等应用中还非常需要单次刺激的多方向驱动反转。液晶弹性体 (LCE) 是软致动器最有吸引力的候选者之一，因为它们具有在 3D 中改变刺激响应形状的能力，并且可以通过 LC 介晶的局部取向进行编程。在这里，报告了一种简单但有效的方法来制造单片 LCE 致动器，该致动器能够通过单个刺激（热）在弯曲和扭曲变形中实现可逆曲率反转。LCE 膜的曲率反转可以通过沿 LC 介晶的厚度和取向的不对称交联密度进行编程。单片 LCE 膜的曲率反转通过加热和冷却表现出高度可逆（超过 100 次）和快速驱动（≈3-5 秒），从而为使用 LCE 材料的实际应用提供了新概念：一种自调节智能阀能够按温度对液体进行定性分选。相信该系统有潜力应用于各种吸热放热化学或生物反应的自调节分选平台