Magnetic programming of 4D printed shape memory composite structures

4D printed shape memory polymers and their composites are currently a highly topical research area. The potential applications for 4D printed smart materials are wide-reaching, with particular promise for personalized medicine. In this work, we 4D printed various structures made of biocompatible and biodegradable polylactic acid (PLA) and PLA/Fe3O4 composite filaments. The shape memory behaviors of the 4D printed structures triggered by magnetic field were investigated. The printed structures can return to their original shapes with a high speed in just a few seconds. Moreover, the structures like bone tissues printed by PLA/Fe3O4 composites filaments with 15% Fe3O4 were actuated by magnetic field at 27.5 kHz. During the shape recovery process, surface temperature of the printed structures is uniform and around 40 °C. This physiologically relevant operating temperature range is a highly attractive feature for potential healthcare and biomedical applications.