Moisture-Harvesting Silicone Rubber Composite with Repeatable Large Actuation via Liquid-Gas Phase Transition

This paper reports on a moisture-harvesting silicone rubber composite capable of repeatable large actuation by liquid-gas phase transition, as a promising material for soft thermal actuators. The composite, fabricated by dispersing silica gel particles within a silicone rubber matrix, absorbed ambient moisture, resulting in a mass increase of approximately 1.6% after 2 h in a humidified environment. The composite exhibited repeatable displacements ($\delta/L=0.18$, displacement-to-length ratio). These results demonstrate its ability to harvest environmental moisture as a fuel for actuation and to repeat large actuations, highlighting its potential for aquatic soft actuator applications.