Self-healing materials enable free-standing seamless large-scale 3D printing

Three-dimensional (3D) printing has had a large impact on various fields, with fused deposition modeling (FDM) being the most versatile and cost-effective 3D printing technology. However, FDM often requires sacrificial support structures, which significantly complicates the processing and increase the cost. Furthermore, poor layer-to-layer adhesion greatly affects the mechanical stability of 3D-printed objects. Here, we present a new Print-Healing strategy to address the aforementioned challenges. A polymer ink (Cu-DOU-CPU) with synergetic triple dynamic bonds was developed to have excellent printability and room-temperature self-healing ability. Objects with various shapes were printed using a simple compact 3D printer, and readily assembled into large sophisticated architectures via self-healing. Triple dynamic bonds induce strong binding between layers. Additionally, damaged printed objects can spontaneously heal, which significantly elongates their service life. This work paves a simple and powerful way to solve the key bottlenecks in FDM 3D printing, and will have diverse applications.