Abstract:
Electro-driven liquid crystal elastomer (LCE) materials have broad application prospects in soft actuators, artificial muscles and micro-robots. Traditional electro-driven LCE materials are mostly prepared by doping conductive materials (carbon nanotubes, graphene, carbon black, etc.) into the polymer materials. In order to improve the conductivity, it is often necessary to increase the amount of conductive fillers, which leads to the poor mechanical properties and unsatisfactory actuation effect. To solve this problem, the liquid metal/liquid crystal elastomer (LM/LCE) composite film is prepared, then carbon black conductive filler is embedded between two LM/LCE films to obtain an electro-driven carbon black/liquid metal/liquid crystal elastomer (CB/LM/LCE) composite film with a "sandwich" structure. The composite materials are characterized and analyzed by Fourier infrared spectroscopy, differential scanning calorimetry, wide angle X-ray diffraction, scanning electron microscope, universal tensile testing instrument, etc. The results show that the LM/LCE film has excellent mechanical properties. After further embedding carbon black conductive filler between two LM/LCE films, the CB/LM/LCE composite film can perform a reversible electro-driven shrinking deformation with efficient electrothermal conversion effect. Powered by an 80 V direct current supply, the CB/LM/LCE composite film can perform a reversible shape deformation and the surface temperature increases from 30 ℃ to 124 ℃ in 240 s. The shrinkage rate of the CB/LM/LCE composite film reaches 18% in 130 s and the deformation shrinkage increases rapidly in the next 70 s. At 200 s, the maximum shrinkage rate can reach 45%. With a load of 50 g mass, the CB/LM/LCE composite film can still perform a remarkable reversible deformation with a maximum shrinkage rate of 42%.