A 3D soft actuator with shape morphing between bending and twisting

Three-dimensional (3D) soft actuators capable of 3D-to-3D shape morphing have garnered significant research interest. However, realizing multifunctional capabilities remains challenging, as most existing designs are limited to transformations between geometrically similar 3D shapes. To address this limitation, this article presents the design and fabrication of a 3D soft actuator capable of morphing between geometrically dissimilar 3D shapes. The actuator features a bilayer structure fabricated by bonding a liquid crystal elastomer (LCE) layer onto a pre-stretched elastomer substrate. Independent control over the substrate’s pre-stretch direction and the LCE’s alignment direction enables programmable 3D-to-3D shape transformations between dissimilar modes, such as bending-to-twisting or twisting-to-bending. The practical utility of morphing between dissimilar shapes is demonstrated via two applications: a multifunctional 3D gripper performing both grasping and winding, and a soft actuator facilitating directional object manipulation. This work overcomes the restriction of similar deformation modes inherent in many existing actuators, offering enhanced design flexibility for tailoring initial and actuated configurations to specific application requirements.