Encoding Magnetic Anisotropies in Digital Light Processing 3D Printing

Magnetic fields are increasingly used in 4D printing to program matter across multiple length scales, enabling control over both macroscopic structures and nanoscale particle organization. However, their integration into additive manufacturing remains limited by compatibility constraints—such as interference with extrusion or optical access—and the inherent challenge of generating spatially resolved, dynamic magnetic fields. In this work, a digital light processing 3D printing method is introduced that directly encodes programmable magnetic anisotropy during fabrication. By formulating a photocurable resin with magnetic nanoparticles and liquid crystal monomers, composite structures are fabricated that respond to both magnetic and thermal stimuli. A hybrid magnetic system—combining a nested Halbach array with a coaxial coil placed in its inner cavity—enables real-time, 3D control of magnetic fields (in both direction and intensity) during the printing process. This approach enables the alignment of liquid crystal mesogens, magnetic fillers, and the formation of vertically oriented nanoparticle chains. The resulting materials exhibit direction-dependent actuation, shape reconfiguration, and selective conductivity, demonstrating a versatile platform for creating multifunctional and multi-stimuli-responsive devices.