Correlation Between Microscale Magnetic Particle Distribution and Magnetic-Field-Responsive Performance of Three-Dimensional Printed Composites

To date, several additive manufacturing (AM) technologies have been developed for fabricating smart particle–polymer composites. Those techniques can control particle distributions to achieve gradient or heterogeneous properties and functions. Such manufacturing capability opened up new applications in many fields. However, it is still widely unknown how to design the localized material distribution to achieve desired product properties and functionalities. The correlation between microscale material distribution and macroscopic composite performance needs to be established. In our previous work, a novel magnetic field-assisted stereolithography (M-PSL) process was developed, for fabricating magnetic particle–polymer composites. In this work, we focused on the study of magnetic-field-responsive particle–polymer composite design with the aim of developing guidelines for predicting the magnetic-field-responsive properties of the composite. Microscale particle distribution parameters, including particle loading fraction, magnetic particle chain structure, microstructure orientation, and particle distribution patterns, were investigated. Their influences on the properties of particle–polymer liquid suspensions and properties of the three-dimensional (3D) printed composites were characterized. By utilizing the magnetic anisotropy properties of the printed composites, motions of the printed parts could be actuated at different positions in the applied magnetic field. Physical models were established to predict magnetic properties of the composite and trigger distance of fabricated parts. The predicted results agreed well with the experimental measurements, indicating the effectiveness of predicting macroscopic composite performance using microscale distribution data, and the feasibility of using the developed physical models to guide multimaterial and multifunctional composite design.