Implementation of printability for magneto-active soft materials based on programmed 3D printing technique

Magneto-active soft materials fabricated by new paradigms of 3D printing have received considerable interest for various applications owing to their remarkable complex deformation and extraordinary magneto-mechanical properties. The morphology and magneto-mechanical properties of materials prepared by direct ink writing (DIW) 3D printing, on the other hand, are closely related to process and material parameters that are critical in this printing technique. In this study, the morphology of ink filaments printed under different parameters was investigated through theoretical analysis and experimental tests to achieve the implementation. The results demonstrated that the prepared magnetic inks are suitable for DIW, and the predictions based on a simplified hydrodynamic model are basically consistent with the measured data in the experiments. It also showed that the diameter of the extruded ink filaments increases with increasing extrusion pressure, and decreasing printing speed, layer height, and magnetic particle content. Similarly, the magnetic property varies with the nozzle diameter and material composition variations. Using the obtained optimal parameters, several magneto-active rods and plate-like structures with a specific arrangement of microscopic magnetic domains were successfully fabricated. Their magnetically driven behavior further was investigated experimentally and numerically, which revealed a programmed, non-contact remote control, reversible, and multimodal large deformation characteristics. The findings of this study allow a more in-depth understanding and analysis of processing-structure-property correlations of printed magneto-active soft materials, laying the groundwork for personalized customization and versatile development of magneto-mechanical performance.