Multi-Jet Fusion 3D Voxel Printing of Conductive Elastomers

3D voxel printing enables the fabrication of parts with site-specific materials and properties at voxel-scale resolution, while the current research mainly focuses on the variations in mechanical properties and colors. In this work, the design and fabrication of voxelated conductive elastomers using Multi Jet Fusion 3D voxel printing actualized by a newly developed multifunctional agent (MA) are investigated. The MA, mainly consisting of carbon nanotubes and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, serves as an infrared-absorbing colorant, a reinforcement, and a conductive filler simultaneously. By controlling the drop-on-demand dispensing of the agents on thermoplastic polyurethane powder, the electrical conductivity across a single printed part can be tailored over a wide range from 10^-10 to 10^-1 S cm^-1 at a voxel resolution of ≈100 µm. Assembly-free strain sensors comprising conductive sensing layers and insulating frames are fabricated to demonstrate the capability of the technique in manufacturing all-printed wearable devices.