Bio-inspired thermal responsible liquid crystal actuators showing shape and color variations simultaneously

Background: Inspired by butterflies, a series of photonic polymers and butterfly-shaped LC actuators were fabricated using a laser cutter that show reversible curling and color variations simultaneously. Methods: To fabricate a polymer film that shows thermal actuation and color variation simultaneously, cholesteric liquid crystal films consisting of planar and focal-conic alignment layers were designed and fabricated. Significant findings: Photonic polymers were synthesized via a one-step polymerization, which simultaneously show color variation and thermal actuation. The planar-co-focal conic construction of the fabricated liquid crystal films was confirmed using SEM. Upon heating, the planar-co-focal-conic constructed film is observed to curl from the bottom to top direction due to the shrinkage of the top planar layer being higher than that of the bottom focal-conic layer. Both thermally induced reversible U-shaped curling and helical actuations for the as-synthesized planar-co-focal conic films were successfully achieved. Butterfly-shaped LC actuators were fabricated using a laser cutter showing reversible curling and color variations simultaneously. These predesigned liquid crystalline actuators with planar-co-focal-conic layers are expected to show great potential for soft robotics and optical devices.