A class of porous metallic nanostructures: Materials

Colloidal crystals are ordered arrays of particles in the nanometre-to-micrometre size range. Useful microstructured materials can be created by replicating colloidal crystals in a durable matrix that preserves their key feature of long-range periodic structure 1 . For example, colloidal crystals have been used to fabricate structures from inorganic oxides 1 , 2 , 3 , 4 , 5 , polymers 6 , 7 , diamond and glassy carbon 8 , and semiconductor quantum dots 9 , and some structures have photonic properties 4 , 8 , 9 or are patterned on different hierarchical length scales 5 . By using colloidal crystals as templates, we have synthesized a new class of metallic materials with long-range nano-scale ordering and hierarchical porosity.