Traversing Material Scales: Macroscale LBL-Assembled Nanocomposites with Microscale Inverted Colloidal Crystal Architecture.

The introduction of three-dimensional (3D) architecture to functional materials allows for the addition of unique characteristics such as special deformation patterns, negative Poison's ratio, negative thermal expansion, controlled biological interactions, and mass transport properties. It also aids in bridging the dimensional gap between layer-by-layer (LBL) assembled nanocomposites and macroscale applications while retaining the advantages of their nanoscale organization. Fabrication of 3D microscale features by traditional techniques are often restricted to a limited variety of materials and do not include hybrid organic-inorganic nanocomposites. This work describes a new method to synthesize macroscale materials with hierarchically controlled architecture by using LBL deposition in the voids of hexagonally packed arrays of uniform microspheres and can be potentially extended to a large variety of materials. Establishing systematic techniques to produce materials with hierarchical architecture involving nano-, micro-, and potentially millimeter scale features with fairly independent control at all levels, allows for the investigation of structural influences on material properties and for the development of new practical applications due to the unusual combinations of properties that can be achieved.