Aerosol-mediated fabrication of porous thin films using ultrasonic nebulization

High surface area ceramic films and biopolymer films were fabricated by precipitation at room temperature of a reagent aerosol composed of approximately 1 mu m diameter microdroplets laid onto a reactive receiver solution using a completely enclosed system. Calcium phosphate films of up to 340 mu m in thickness composed of hollow microspheres were generated by gradual settling and precipitation of the reagent microdroplets on the receiver solution surface. Suitability of the ceramic film as a drug support using alendronate as an example was investigated. Chitosan/alginate biopolymer films were similarly prepared and precipitation with limitation to the air/water interface promoted a wire form copper oxide precursor. Zirconia microspheres were prepared without use of surfactant or template via precursor precipitation in a stirred receiver solution. Additional components could be readily incorporated and the flexibility of the novel approach is consistent with a new general strategy for the preparation of thin films and hollow microspheres of nanostructured materials.