Voxelated Soft Matter via Multimaterial Multinozzle 3D Printing

Abstract

There is growing interest in voxelated matter that is rationally designed and fabricated voxel-by-voxel1–4. Currently, inkjet-based 3D printing is the only widely adopted method capable of creating 3D voxelated materials with high precision1–4, yet the physics of droplet formation requires the use of low-viscosity inks to ensure successful printing5. By contrast, direct ink writing (DIW), an extrusion-based 3D printing method, is capable of patterning a far broader range of materials6–13. However, it is difficult to generate multimaterial voxelated matter by extruding monolithic cylindrical filaments in a layerwise manner. Here, we report the design and fabrication of voxelated soft matter using multimaterial multinozzle 3D (MM3D) printing, in which their composition, function, and structure are programmed at the voxel scale. Our MM3D printheads exploit the diode-like behavior that arises when multiple viscoelastic materials converge at a junction to enable seamless, high frequency switching between up to eight different materials to create voxels whose volume approaches the nozzle diameter cubed. As exemplars, we fabricated a Miura origami pattern14 and a millipede-like, soft robot that locomotes by co-printing multiple epoxy and silicone elastomer inks, respectively, whose stiffness varies by several orders of magnitude. Our method substantially broadens the palette of voxelated materials that can be rationally designed and manufactured in complex motifs.