Ultra-soft Organogel Artificial Muscles Exhibiting High Power Density, Large Stroke, Fast Response and Long-Term Durability in Air.

Abstract

Polymeric gel-based artificial muscles exhibiting tissue-matched Young's modulus (10Pa-1MPa) promise to be core components in future soft machines with inherently safe human-machine interactions. However, the ability to simultaneously generate fast, large, high-power and long-lasting actuation in the open-air environment, has yet been demonstrated in this class of ultra-soft materials. Herein, to overcome this hurdle, we report the design and synthesis of a twisted and coiled liquid crystalline glycerol-organogel (TCLCG). Such material with a low Young's modulus of 133kPa can surpass the actuation performance of skeletal muscles in a variety of aspects, including actuation strain (66%), actuation rate (275%/s), power density (438kW/m3 ) and work capacity (105kJ/m3 ). Notably, its power density is 14 times higher than the record of state-of-the-art polymeric gels. No actuation performance degradation is detected in the TCLCG even after air exposure for 7 days, owing to the excellent water retention ability enabled by glycerol as co-solvent with water. Using TCLCG, we have successfully demonstrated mobile soft robots with extraordinary maneuverability in unstructured environments, including a crawler showing fast bidirectional locomotion (0.50mm/s) in a small-confined space, and a roller that can escape after deep burying in sand. This article is protected by copyright. All rights reserved.