Liquid Crystal Elastomers in Focused Ultrasound Fields

ABSTRACT Liquid crystal elastomers (LCEs) combine molecular anisotropy with elastic softness, enabling programmable and reversible shape transformations that make them promising candidates for soft robotics. However, achieving localized, rapid, and remotely controlled actuation of LCEs without embedded components is a continuing challenge. Here, we introduce focused ultrasound (FUS) as a non‐invasive stimulus for remotely actuating pre‐programmed LCEs. We demonstrate that a pre‐programmed LCE strip exposed to FUS undergoes rapid and reversible bending deformation driven by a localized acousto‐thermomechanical effect, wherein acoustic energy is converted into heat within the viscoelastic network, triggering the nematic–isotropic transition and inducing contraction along the nematic director. We characterize the FUS‐induced temperature field and dynamic response to reveal how the LCE geometry, crosslinking density, and ultrasound parameters govern the actuation kinetics. The results expose three key advantages: ultrasound enables remote and wireless actuation; the response relies solely on the intrinsic viscoelasticity of the LCE– without the need to embed optical or magnetic components in LCEs; and the spatiotemporal tunability of FUS allows localized and sequential activation within LCEs. Together, these findings establish an acoustic‐based actuation paradigm for LCEs, paving the way toward intelligent, reconfigurable, and remotely powered soft robotic systems.