Recent progress in 4D printing: materials, methods and applications

Purpose This review presents a brief overview of four-dimensional (4D) printing. The review focuses on how additive manufacturing methods, stimulus-responsive materials and application-driven design considerations enable time-dependent shape and property evolution in printed structures. Design/methodology/approach Recent advances in 4D printing are systematically reviewed, including key additive manufacturing techniques and emerging processes, as well as major classes of stimulus-responsive materials. Representative applications, including origami-inspired foldable structures, biomedical devices and soft robotics and adaptive structures, are examined to illustrate the interaction between the printing methods, material selection and functional performance. Findings The review indicates that material extrusion and vat photopolymerization currently dominate 4D printing since they offer the most practical combination of process accessibility, material compatibility and control of programmed shape change. Shape memory polymers remain the most widely used materials, while hybrid and multi-material approaches are increasingly enabling more localized and multifunctional actuation. A key finding of this review is that the behavior of 4D-printed structures is governed by the interaction among the fabrication method, material response, activation mechanism and structural design rather than by a single factor alone. The analysis also shows that long-term reliability, manufacturing scalability and design predictability remain major barriers to wider application. Originality/value The review adopts a method-material-application-centric perspective that provides a structured synthesis of fabrication techniques, responsive material classes and practical use cases. Moreover, the review offers a clear foundation for future research and application-oriented development in 4D printing.