Multi‐Material 3D and 4D Printing: A Survey

Recent advances in multi‐material 3D and 4D printing (time as the fourth dimension) show that the technology has the potential to extend the design space beyond complex geometries. The potential of these additive manufacturing (AM) technologies allows for functional inclusion in a low‐cost single‐step manufacturing process. Different composite materials and various AM technologies can be used and combined to create customized multi‐functional objects to suit many needs. In this work, several types of 3D and 4D printing technologies are compared and the advantages and disadvantages of each technology are discussed. The various features and applications of 3D and 4D printing technologies used in the fabrication of multi‐material objects are reviewed. Finally, new avenues for the development of multi‐material 3D and 4D printed objects are proposed, which reflect the current deficiencies and future opportunities for inclusion by AM. The present work reviews the state of the art in multi‐material 3D and 4D (time as the fourth dimension) printing with a special focus on polymers, ceramics and their associated composites as printing materials. This review‐type article compares the advantages and limitations of various multi‐material 3D and 4D printing technologies, represents many printed multifunctional parts for various applications ranging from aerospace to biomedical, and provides future directions the technologies discussed.