Exploring the Design Space of Polycatenated Metamaterials*

Polycatenation, a phenomenon originated from polymer chemistry, delineates the process of conjoining multiple enclosed molecular loops or knots to form a more expansive and complex ensemble. These polycatenated configurations, due to their unique topologies, inherently exhibit variant degrees of freedom among their constituent units, all the while preserving their overarching polyknotted structures intact. Translating this molecular paradigm to the realm of mechanical metamaterials presents a transformative opportunity for the metamaterial design. In this study, we report a rational design platform based on topologically interlocking wireframes, allowing the creation of polycatenated metamaterials with tailor-made global structural pliancy. Our comprehensive investigations show that these polycatenated metamaterials can be engineered to display highly customizable mechanical properties, determined by their topological and geometric designs, including fluid-like to solid-like phase transitions. The introduction of polycatenated structures adds a new dimension in the design of architected materials and thereby offers new functionalities for application in impact protection, wearable materials and soft robotics.