Shape Morphing by Topological Patterns and Profiles in Laser-Cut Liquid Crystal Elastomer Kirigami

Abstract

Programming shape changes in soft materials requires precise control of the directionality and magnitude of their mechanical response. Among ordered soft materials, liquid crystal elastomers (LCEs) exhibit remarkable and programmable shape shifting when their molecular order changes. In this work, we synthesized, remotely programmed, and modeled reversible and complex morphing in monolithic LCE kirigami encoded with predesigned topological patterns in its microstructure. We obtained a rich variety of out-of-plane shape transformations, including auxetic structures and undulating morphologies, by combining different topological microstructures and kirigami geometries. The spatiotemporal shape-shifting behaviors are well recapitulated by elastodynamics simulations, revealing that the complex shape changes arise from integrating the custom-cut geometry with local director profiles defined by topological defects inscribed in the material. Different functionalities, such as a bioinspired fluttering butterfly, a flower bud, dual-rotation light mills, and dual-mode locomotion, are further realized. Our proposed LCE kirigami with topological patterns opens opportunities for the future development of multifunctional devices for soft robotics, flexible electronics, and biomedicine.

Shape Morphing of 3D Printed Liquid Crystal Elastomer Structures with Precuts

“…The LCEs can exhibit complex shape transformations by carefully programming the geometries and orientation patterns. − Peng et al proposed an approach for realizing 4D printing of freestanding LCE by the integration of laser-assisted DIW and DLP, which provide design freedom and fabrication capability for applications. Wang et al prepared a photothermal composite ink AuNR/LCE and demonstrated that 3D-printed AuNR/LCE flower whose petals can be “bloomed” globally or individually.…”

Finite element modeling of programmable liquid crystal elastomer plates and its application in text display

“…Hillel et al 43 used an approximate numerical method to calculate local LCE deformation curvature, achieved programmable arbitrary LCE three‐dimensional shape deformation, and created a 3D “Robot face”. Chen et al 44 proposed LCE kirigami with topological patterns and implemented different functionalities, such as a bioinspired fluttering butterfly, a flower bud, dual‐rotation light mills, and dual‐mode locomotion. Based on the principles of muscles, Mengqi et al 45 enabled programmable LCE muscles to achieve diverse motions through the cooperative actions of otherwise simple contraction/expansion of individual muscle bundles.…”