Magnetically Responsive Melt Electrowritten Structures

While melt electrowriting (MEW) can result in complex microstructures, research demonstrating such fabrication with active materials is limited. Herein, magnetoresponsive poly(ε‐caprolactone) (PCL) inks containing up to 10 wt% of iron‐oxide (Fe3O4) nanoparticles are used to produce fiber with diameters of 9.2 ± 0.6 µm in ordered microstructures when processed by MEW. Introducing the Fe3O4 nanoparticles has a minimal overall effect on printing quality compared to pure PCL under similar conditions. The magnetic response of Fe3O4 containing fibers allows magnetic actuation, which is one of the first steps to control movement in such structures. Printed samples show different magnetic responses that can be controlled by the micro‐ and macro‐structure design, the nanoparticle concentration, and multi‐material design. The potential of MEW to print active magnetic complex micro‐ and macro‐structures for 4D printing designs is demonstrated, in which active properties can be further tailored with magnetoresponsive fillers with varying characteristics and by changing MEW fiber diameters. Melt electrowriting (MEW) can create complex microstructures, but research is limited for active materials. Herein, magnetoresponsive inks are used to produce microfibers via MEW into ordered microstructures and the resulting magnetic actuation controls their movement. The potential of MEW to print active magnetic complex structures for 4D printing designs is demonstrated.