Morphological Control of Hybrid Nanomaterials

Nature uses layered hybrid materials with structure at the nano-level to combine the properties of organic and inorganic components to achieve potential advantages such as toughness, high strength, and low density. These functional materials also allow exploration of the relationship between structure, composition, and properties. We report the preparation and properties of a hybrid Al₂O₃ / PMMA composite with a tunable lamellar structure, prepared through a two-step method: fabrication of inorganic scaffolds by ice templating ("freeze-cast" method) followed by infiltration of polymers in the interstices left after the ice has been removed by freeze drying. The lamellar structure of the inorganic material is promoted by using slurries with two alumina sources, allowing control of the lamellar thickness and porosity of the ceramic scaffolds. Owing to their lamellar structures, the final hybrid nanocomposites show anisotropic physical properties. In particular, the thermal conductivity and sample hardness can be tailored by controlling the thickness of Al₂O₃ lamellae or infiltrated PMMA, deepening our understanding of the relationship between structure and properties of materials.