Rotational Multi-material 3D Printing of Soft Robotic Matter with Asymmetrical Embedded Pneumatics

The rapid design and fabrication of soft robotic matter is of growing interest for shape morphing, actuation, and wearable devices. Here, we report a facile fabrication method for creating soft robotic materials with embedded pneumatics that exhibit programmable shape morphing behavior. Using rotational multi-material 3D printing, asymmetrical core-shell filaments composed of elastomeric shells and fugitive cores are patterned in 1D and 2D motifs. By precisely controlling the nozzle design, rotation rate, and print path, one can control the local orientation, shape, and cross-sectional area of the patterned fugitive core along each printed filament. Once the elastomeric matrix is cured, the fugitive cores are removed, leaving behind embedded conduits that facilitate pneumatic actuation. Using a connected Fermat spirals pathing approach, one can automatically generate desired print paths required for more complex soft robots, such as hand-inspired grippers. Our integrated design and printing approach enables one to rapidly build soft robotic matter that exhibits myriad shape morphing transitions on demand.