Click metamaterials: Fast acquisition of thermal conductivity and functionality diversities

In material science, the development of metamaterials is crucial for advancing various technological applications. However, most metamaterial designs are still case by case due to lacking a fundamental mechanism for achieving reconfigurable thermal conductivities, largely hindering design flexibility and functional diversity. Inspired by the principles of click chemistry, known for its modular and efficient approach to creating molecular diversity, here we propose a universal concept of click metamaterials for fast realizing various thermal conductivities and functionalities. Tunable hollow-filled unit cells are constructed as the modified building blocks to change the thermal conductivity locally. Different configurations of unit cells with variable fill fractions can generate convertible thermal conductivities from isotropy to anisotropy, allowing click metamaterials to exhibit environment-free and reconfigurable thermal functionalities. The straightforward structures enable full-parameter regulation and simplify engineering preparation, making click metamaterials a promising candidate for practical use in other diffusion and wave systems.