Self‐Healing, Photothermal‐Responsive, and Shape Memory Polyurethanes for Enhanced Mechanical Properties of 3D/4D Printed Objects

Abstract Additive manufacturing is a promising technology that can directly fabricate structures with complex internal geometries, which is barely achieved by traditional manufacturing. However, the mechanical properties of fused deposition modeling (FDM)‐printed objects are inferior to those of conventionally manufactured products. To improve the mechanical properties of the printed products, a series of novel thermoplastic polyurethanes with self‐healing properties, intrinsic photothermal effects, and excellent printability are designed and synthesized by introducing dynamic oxime–carbamate bonds and hydrogen bonds into the polymer chains. On‐demand introduction of near‐infrared (NIR) irradiation, direct heating, and sunlight irradiation enhances interfacial bonding strength and thus improve the mechanical properties of the printed product. Additionally, mechanical anisotropy of the printed products can be sophistically manipulated by regulating the self‐healing conditions. Support‐free printing and healing of damaged printed products are also achieved owing to the self‐healing properties of the material. Moreover, the as‐prepared materials exhibit shape‐memory properties NIR irradiation or direct heating effectively triggers shape‐memory recovery and demonstrates their potential in 4D printing by printing a man‐like robot. This study not only provides a facile strategy for obtaining high‐performance printed products but also broadens the potential applications of FDM technology in intelligent devices.