Elastic and ultra stable ionic conductors for long-life-time soft robots working at extreme environments

摘要

There is a pressing need for soft robots capable of rapid movement at extreme environments, necessitating the development of ionic conductors with high ionic conductivity, low Young’s modulus, high elasticity, and high stability at extreme environments. However, existing ionic conductor materials cannot meet all of above needs. The preparation of water-free ionic conductive organogels is expected to solve the above problems. In this work, we design a synergy strategy to combine ion-dipole interactions with hydrogen bonds and successfully obtain ethylene glycol (EG) gels at a low polymer concentration of 5 mol%. Our EG gels possess high ionic conductivity (1.31 mS cm−1), low Young’s modulus (7.3 kPa), high elasticity (~100%), and good extreme environmental stability. The EG gels can work stably for long time at extreme environments (−27 to 123 °C and 10% to 70% relative humidity (RH)). Furthermore, we successfully achieved dielectric elastomer actuator devices stable operation at extreme environments and with 42 times longer lifetime than commonly used ionogels. We also achieved a soft robot that can work stably at extreme environments with a high speed of 3.6 BL s−1 (body lengths per second). There is a need to design soft robots for rapid movement in extreme environments, though it is a challenge to balance electronic and mechanical properties while being stable in extreme conditions. Here the authors design an ethylene glycol gel which balances stability with its electronic and mechanical performance.