Fig. 1. Fabrication methods of liquid crystal elastomer： 3D printing， dry spinning， wet spinning， template method.

Fig. 2. （a） Mechanism of the deformation of liquid crystal elastomer actuated by heat^［35］； （b~g） Liquid crystal elastomer artificial muscle preparation by dry spinning and its performance under thermal actuation^［36］； （h~j） Liquid crystal elastomer artificial muscle process prepared by template method and its performance under thermal actuation^［37］.

Fig. 3. （a~f） Performance of liquid crystal elastomer artificial muscles containing liquid metal interlayers under electrical actuation^［38］； （g~i） Performance of liquid crystal elastomer artificial muscles containing carbon black interlayers under electrical actuation^［44］； （j） Preparation process of liquid crystal elastomer artificial muscles containing gold nanocoating^［46］； （k~o） Performance of liquid crystal elastomer knotted artificial muscles prepared together with flexible wire braiding under electrical actuation^［47］.

Fig. 4. （a~c） Driving mechanism and driving performance of liquid crystal elastomer artificial muscles embedded with NdFeB particles under magnetic fields^［48］. （d~f） Wireless magnetic actuation of magnetic particle liquid crystal elastomer artificial muscle （M-PULCE） in a closed robotic arm. The actuator performs contraction movement driven by the magnetic field， driving the mechanical arm to bend. （e~j） Various actuation motion modes of M-PULCEs under AMF. Scale bar： 5 mm^［50］.

Fig. 5. （a，b） DR1-LCE jumping actuator with a closed-loop structure enabled by photo-mechanical coupling^［57］； （c，d） Schematic diagram of GNR/LCE composite film driven by near-infrared light^［54］.

Fig. 6. （a） Schematic of monodomain h-LCE activation by acidic solution and its bending behavior upon exposure to moisture； （b） Contact angles of an h-LCE before and after activation； （c） FTIR spectra of an h-LCE before and after activation^［61］.

Fig. 7. Comparison of the actuation performance of natural muscles and liquid crystal elastomer artificial muscles^{［1，25，62-64］}

Fig. 8. （a） Schematic of main-chain LCE synthesis via thiol-acrylate Michael addition reaction. During synthesis， mesogens are in the isotropic phase in a present of solvent （toluene） at 60 ℃^［66］. （b） Schematic illustration of the preparation of dopamine layer on liquid crystal elastomer^［68］.

Fig. 9. （a） Actuation mechanism of LCE fiber and POM images of polydomain， monodomain， and isotropic states of LCE microfibers observed at two different angles with respect to the analyzer. Scale bars： 200 μm ［middle］， 20 μm ［right］， and 200 μm ［bottom］. （b） Uniaxial tensile tests （at 25 ℃） of as-spun LCE microfibers with different diameters （22~66 μm）. （c） DSC trace of as-spun LCE microfiber^［62］. （d） Fabrication process of knotted artificial muscles. The two insets are the POM images （scale bar： 200 µm） before and after the LCE is printed， showing the alignment of the liquid crystals. （e） Knotted structure greatly amplifies the actuation performance of the LCE material， leading to high stroke and high frequency actuation^［47］.

Fig. 10. Soft robot based on liquid crystal elastomer artificial muscles. （a） Robotic arm based on liquid crystal elastomer artificial muscles； （b） By controlling the stimulation time of the LCE-based motor unit， the oscillation dynamics of the arm after one perturbation can be tuned^［46］； （c） Slit robot based on liquid crystal elastomer artificial muscles^［80］； （d，e） Hill-climbing robot based on liquid crystal elastomer artificial muscles. Scale bar： 1 cm^［81］.

Fig. 11. （a） Deformation process of the active compliant mechanism for in vivo surgery； （b） Deformation process of the active compliant mechanism^［83］.

Fig. 12. Breathable， shrinkable， hemostatic patch for enhanced skin regeneration with round and cross-shaped wounds in a rat model based on liquid crystal elastomer artificial muscle. （a） Schematic illustration of the shrinkable， hemostatic patch consisting of two layers （i.e.， liquid crystal elastomer artificial muscle and acrylate dressing）； （b） Schematic illustration of working mechanism of the shrinkable， hemostatic patch for skin regeneration； （c） Optical image for dozens of hemostatic patches； （d~f） Optical images for the process of full-thickness， round skin wound operation in a rat model. Scale bars is 1 cm^［82］.