Authors: X. Jiang
Affilation: Changzhou University, China
Pages: 431 - 433
Keywords: hollow sphere, aerosol, evaporation, sol gel, droplet
Hollow nanospheres and nanofoams possess characteristics such as low density, high surface area and adjustable refractive index that make them attractive to tune their mechanical, optical, electrical, and chemical properties for applications ranging from drug and gene delivery, catalysts, antireflective coatings and wave absorbing, energy storage and supercapacitor, low dielectric constant substrates, chemical and biological sensing, labeling, and early detection of cancer, metamaterials, optoelectronics, and photovoltaics. Currently, laser ablation, molecular beam epitaxy, and chemical vapor deposition have been applied for fabrication of hollow and core/shell structured nanospheres. Hollow metal, sulfide, and oxide spheres have been synthesized by self-assembly in the presence of hard and soft templates. However, most often the template cores are difficult to remove for contamination-free hollow structures. In this work, we report a novel room-temperature fabrication method for metal oxide hollow nanospheres and nanofoams by a single-step template-free aerosol process using low boiling-point hydrophobic solvent by controlling mass transport and sol gel reactions at droplet interface. Chemical engineering aspects associated with the aerosol process are discussed and analyzed for better control of the morphology and nanostructure. The facile technique is important for applications such as drug delivery, wave absorption, catalysts, sensors, and energy storage.