Additive Manufacturing of Cobalt Iron Oxide-Based Photopolymer Resin Magnetoactive Polymer Composites Through Stereolithography

Magnetoactive polymer composites (MAPCs) are smart materials composed of polymers integrated with magnetic nano/particles. MAPCs are capable of transforming shapes and properties under an external magnetic field, and this behavior makes them attractive for applications in soft robotics, biomedical devices, and remote actuation systems. In this study, stereolithography (SLA), an additive manufacturing (AM) process, was used to develop novel MAPCs. Cobalt iron oxide (CIO) nanoparticles were incorporated into a photopolymer resin at varying concentrations (0.25%–1% wt) to develop MAPCs optimized for SLA, followed by post-processing and optimization. SLA process was fine-tuned with parameters set at 0.05 mm layer height, 40 s exposure time, and 70 s bottom exposure time, producing structures with high dimensional accuracy and surface quality. 3D-printed structures were characterized through detailed physiochemical analysis, including morphological (EDS, TOF-SIMS), chemical (FTIR), and magnetic properties through actuation testing and vibrating sample magnetometry (VSM). EDS and TOF-SIMS confirmed the presence of CIO nanoparticles and the preservation of CIO stoichiometry. Mechanical testing revealed that the optimal tensile strength of 11.36 MPa was achieved at 0.50% CIO loading, while the maximum flexural strength of 6.56 MPa was observed at 0.75% CIO. The results indicate that moderate CIO additions improve MAPC ductility, whereas higher loadings reduce strength, likely due to agglomeration and poor matrix-nanoparticle bonding. Finally, the magnetic properties revealed the maximum saturation magnetization (M_s) and remanence (M_r) of 0.4615EMU/g and 0.273EMU/g, respectively, for resin/1% CIO MAPCs. Hence, increasing CIO concentration, the magnetic responsiveness of the MAPCs enhances. These results demonstrate the potential of SLA-fabricated MAPCs for functional applications, such as sensors, actuators, biomedical implants, and other advanced engineering devices.