Advances in 3D and 4D Printing of Soft Robotics and Their Applications

Soft robots inspired by natural organisms exhibit unprecedented deformation abilities for diverse applications leveraging various smart materials, intelligent structures, and actuation principles. At the same time, advancements in 3D printing technology empower contemporary 3D printers with higher resolution, faster printing speed, and a broader selection of materials. The progression of 3D printing technologies offers additional avenues for fabricating soft robots, facilitating their practical utilization, and commercialization. This review summarizes fundamental 3D printing principles, encompassing fused filament fabrication, direct ink writing, vat photopolymerization, material jetting, and selective laser sintering and emphasizing their capabilities in material selection, multimaterial printability, soft robot fabrication, and smart material printing. This article is concluded with applications of 3D- and 4D-printed soft robots and perspective on future designs and fabrication strategies is offered. This article bridges the gaps between soft polymers, 3D printing technologies, soft actuators, and robotic applications, providing guidance for multidisciplinary researchers in the domains of 3D printing and soft robotics.