Soft\nArtificial Muscle\nof Poly(vinyl chloride) Gel\nwith an Imperceptible Liquid Metal Electrode

Electrodes\nwith high electrical conductivity, yet good\nflexibility\nand mechanical compliance, are critical for electroactive artificial\nmuscles. Herein, a promising liquid metal (LM) electrode is proposed\nby transforming eutectic gallium–indium (EGaIn) LM with high\nsurface tension into paste-like LM with solid Ga<sub>2</sub>O<sub>3</sub> shells. The developed compliant LM electrode not only shows\nhigh conductivity and negligible additional stiffness but also displays\nexcellent electrical stability during cyclic actuation. Based on the\nLM electrode, the poly(vinyl chloride) gel (PVCG) artificial muscle\ndeveloped exhibits the maximum actuation strain of 18.7% at a low\nelectric field strength of 9 V μm<sup>–1</sup> and maintains\nexcellent durability without obvious performance attenuation after\n10,000 s. A comparison shows that the as-developed PVCG artificial\nmuscle is superior over that based on widely used carbon electrodes.\nMoreover, an artificial upper limb and crawling worm were manufactured\nto explore the great potential of PVCG artificial muscle in the robotic\nfield. In addition, the practical application demonstration of the\nPVCG artificial muscle in the biomimetics field is also successfully\nfulfilled through the design of reasonable structures. Due to its\neasy fabrication, excellent electrical conductivity, and high mechanical\ncompliance, the newly developed LM electrode is promising for high-performance\nPVCG artificial muscles in bionic robots.