Atomic layer deposition of uniform metal coatings on highly porous aerogel substrates

A new templating method that utilizes atomic layer deposition (ALD) process to deposit conformal metal films inside high aspect ratio structures, for the fabrication of porous metal nanostructures, is introduced. Aerogels are a special class of of low-density, open-cell foams with submicrometer architectures, and are ideal templates for the preparation of nanocellular metal foams. This method has been successfully employed for the preparation and characterization of tungsten (W)-coated alumina and germania aerogels. Microstructural analysis of these materials showed that tungsten deposition was uniform throughout each template. It is also observed that the morphology of the deposited metal depends on the surface chemistry of the skeletal aerogel network. The porosity and density of the metal foam, resulting from this approach, can be reliably controlled through the selection of aerogels template and the number of metal deposition cycles.