4D Printing of Programmable Liquid-Vapor Phase Change Composites for Multi-Responsive Flexible Actuators

Abstract

Flexible intelligent materials are extensively utilized in fields such as soft robotics and flexible electronic devices due to their high tensile strength, reversible deformation, and environmental adaptability. A novel magneto-thermal responsive liquid-vapor phase transition composite material is proposed, integrating expansion deformation and load-bearing functions. The liquid-vapor phase change of low-boiling-point liquids within the elastomer is driven by the magnetocaloric effect of nano-Fe3O4 particles. The bilayer structure, which combines active and passive layers, can achieve various structures and deformations. The liquid-vapor phase change material serves as the active layer, providing reversible expansion deformation, while the silicone elastomer functions as the passive layer, providing constraint, thus driving the bilayer structure to bend and expand. Functional actuators suitable for different applications, such as flexible grippers, load-bearing dome structures, and on-demand deformation switches, were manufactured using 3D printing technology. Additionally, dual-response targeted delivery structures were developed by combining dynamic and static magnetic fields. These flexible actuators combine multiple characteristics, including customizable structures and deformations, reversible expansion deformation, stretchability, and load-bearing capacity, potentially opening new application avenues in flexible electronic devices and soft robotics.