Multi‐Responsive 4D‐Printed Soft Active Material toward Shape‐Reconfigurable Actuators

Abstract

Abstract The development of 4D‐printed soft active material (SAM) with programmable shape transformations and multifunctional properties remains a critical challenge for soft active materials. In this study, a 4D‐printed, dual‐responsive SAM is designed by integrating a 4‐arm star poly(N, N‐dimethyl acrylamide)‐ block ‐poly(dimethyl amino ethyl methacrylate)‐Br (4‐arm star (PDMA ‐b‐ PDMAEMA) 4 ‐Br) diblock copolymer with acrylic acid (AA), enabling precise shape morphing, tunable mechanical performance, and multi‐stimuli responsiveness. The SAM demonstrated excellent 3D printing, enabling the fabrication of complex 3D architectures with pre‐designed infill patterns. It exhibited high shape fixation and rapid shape recovery upon thermal activation at 44 °C. Moreover, its pH‐responsive swelling behavior facilitated selective dye removal, achieving ≈96% uptake of a model cationic dye at pH 10.5 and ≈65% uptake of a model anionic dye at pH 4.5. The SAM‐based robotic actuator successfully lifted weights, showcasing its potential for soft robotics applications. The integration of shape‐memory behavior with functional applications highlights the potential of this smart material in sustainable environmental technologies and advanced safety systems. These findings highlight the versatility of SAM for 4D‐printed adaptive systems, offering promising applications in biomedical engineering, and intelligent actuators.