Liquid Crystal Elastomer Hollow Fibers as Artificial Muscles with Large and Rapid Actuation Enabled by Thermal‐Pneumatic Enhanced Effect

Abstract

AbstractLiquid crystal elastomer (LCE) has large and reversible deformation under stimulation, making it an ideal material for artificial muscles. Currently, multi‐stimulus responsive LCE actually responds to each stimulus independently rather than responding to several stimuli simultaneously. Achieving an enhanced effect from concurrent stimuli is still a challenge, which requires a new stimulus‐response mechanism. This work develops a novel and facile solvent evaporation‐assisted template method to prepare LCE hollow fiber (LCEHF) with axial alignment. Taking advantage of the enhanced effect of heat‐induced phase transition and mechanical force‐induced orientation transition of mesogens, the LCEHF under both heat and pressure can produce a large contraction ratio of ≈50%, which is higher than 42% of thermal stimulation or 27% of pneumatic stimulation. It can also enhance the respective response and recovery speed of LCEHF to 300 and 3700 times of pneumatic actuation. Additionally, the enhanced effect lowers the actuation temperature much below the phase transition temperature, imparting LCEHF with high mechanical performance during actuation. Furthermore, the dual thermal‐pneumatic responsive LCEHF can mimic human biceps and cause large and rapid bending of an artificial arm reversibly. This new actuation methodology sheds new light on improving LCE actuation performance and broadens its application scenarios.