Novel liquid–gas phase change soft actuator for high efficiency drive and its underwater application

Abstract This paper presents a novel spin-thermal transient heating method for liquid–gas phase change soft actuators that utilize material volume changes for actuation. Traditional heating methods require direct contact between the liquid and the heater, leading to increased voltage for vaporization. To overcome challenges associated with miniaturization and lightweighting, a new actuator monomer is designed, and a volume expansion model is established. Theoretical analysis identifies the optimal low-boiling liquid amount for various monomers. Experimental results show a 94.12% increase in heating efficiency, a 67.65% reduction in start-up response time, and a 45.46% improvement in maximum expansion compared to traditional methods. The paper also examines the effects of temperature difference and saturated vapor pressure on heating efficiency. Furthermore, it explores deformation and combination mechanisms, leading to the development of a windmill-type underwater actuator and a center of gravity adjustment device. Experimental results demonstrate a stable rotation of 30 s for the windmill actuator and a stable motion period of 15 s for the adjustment device, providing an innovative solution for efficient actuation in flexible underwater applications.