Polymer-inspired mechanical metamaterials

Metamaterials benefit from unique architected patterns to achieve lightweight with exceptional mechanical properties inaccessible to conventional materials. Typical mechanical metamaterials are inspired by crystal-like lattice structures, whose closely packed frameworks often exhibit a rigid mechanical nature. Here, we present polymer-inspired metamaterials (PIMs) by programming deformation and strengthening mechanisms that mimic the mechanical roles of key constituent elements in polymer networks. By combining metamaterial programmability with polymer-inspired structures, we design crosslinking, proto-crystalline order, and entanglement in PIMs to enable macroscale strengthening mechanisms inspired by crosslink, molecular-density, and pre-stretch strengthening in polymers, expanding the metamaterial structure-property design space. This macroscale polymer-inspired programmability is demonstrated through PIM-based soft robotic components, including programmable humanoid tissues, robotic fingers, toes and feet, and soft biomimetic exoskeletons. Inspired by polymer microstructures and toughening mechanisms, the authors introduce a class of programmable polymer-inspired metamaterials that expand lattice-property limits and are naturally suited to soft robotics and humanoid tissues.