Study on Biomimetic Photo/Thermal Tunable Liquid Crystalline Elastomeric Actuators

Abstract

Recently due to the rapid progress in soft actuator and robotics novel soft materials with different and complex shape change such as helical curling self-oscillation folding and other three-dimensional shape morphing were highly investigated In this research a series of photo/thermal tunable liquid crystalline actuators was fabricated via thiol-acrylate Michael addition The molar ratio between acrylate and thiol functional groups was controlled to ensure acrylate groups are excessive for the second crosslinking reaction To synthesize elastomeric polymers showing liquid crystal phases RM257 was used as a main chain liquid crystalline monomer A synthesized monomer 4 4’-bis(6-(acryloyloxy)hexyloxy) biphenyl (BAHB) was used to adjust the mechanical strength After polymerization the monodomain aligned film was achieved by uniaxial stretching and the anisotropic properties of the polymer film were confirmed by polarized optical microscope (POM) The fabricated liquid crystal elastomeric film shows a series of reversible shape changing such as helical curling elongation and contraction This phenomenon is ascribed to the change of molecular orientation triggered by temperature Finally a caterpillar-like liquid crystal elastomer (LCE) was fabricated To enhance the photo sensitivity the film was soaked in the polydopamine (PDA) solution for overnight With the photo-thermal effect of the polydopamine on infrared light the prepared LCE film shows caterpillar-like moving The results suggest that the synthesized LCE actuator can effectively transfer the photo and thermal energy into mechanical power resulting in the caterpillar-like moving The synthesized photo and thermal sensitive films are expected to show lots of potential applications in biomimetic devices and micro robotic system

Date of Award	2020
Original language	English
Supervisor	Jui-Hsiang Liu (Supervisor)