Multimode coaxial extrusion of segmented core-shell structures for soft metamechanics and biomimetic applications

The unique ability to combine versatile materials via additive manufacturing greatly enhances the functionalities of soft machines. However, manufacturing for multi-material devices often involves complex and redundant procedures. Herein, we develop a multimode coaxial direct ink writing method for efficient 3D printing of multi-material filaments in the form of core-shell material distribution at millimeter scales. Through simulations and experiments, essential printing parameters, such as extrusion pressure and deposition speed combinations, are investigated to control compositions simultaneously. As exemplars, we fabricate soft lattices presenting tunable mechanical responses by printing soft and tough silicone in a single pass. We also demonstrate bio-mimetic potentials by fabricating soft fingers and magnetic shape-shifting structures with multiple functional materials. Our method is expected to provide a new paradigm for designing and manufacturing the rapid prototyping of soft functional machines.