S. Poges, P. Firth, J. Lee, J. Carpenter, J. Adamczyk, E.S. Toberer, C. Hogan, Z.C. Holman
Arizona State University,
Keywords: thermal Insulation, Window coatings, silica nanoparticles, aerosol spraying
Summary:The overarching goal of our coating technology is to substantially reduce heat loss—and thus primary energy consumption—from residential and commercial windows by developing replacement panes with similar price and appearance but substantially lower U-factor and condensation temperature within their class. To reach this goal, our team synthesizes a highly porous silica nanoparticle network through plasma synthesis and aerosol impaction. The Aerosol Impaction-Driven Assembly (AIDA) system gives us full control of these coatings with tunable refractive index (100 m/s. In order to create highly porous (85%) optical coatings composed of silica, we synthesize 5 nm particles in a dusty plasma. While the AIDA tool can accommodate solid, liquid, and gaseous precursors, our silica production is primarily from a silane and air mixture. To date, we have characterized our coatings with thicknesses of 0.1 mm to 1 mm. All coatings in this range with a porosity of 85% yield thermal conductivities 80%. However, other optical properties suggest our coatings need further improvement. Haze has been the teams #1 challenge throughout the development of this technology. As expected, the haze seen in our films increases from ~1% with our thin 0.1 mm prototypes to ~8% in 1 mm prototypes. Through experimentation and literature review, we are beginning to combat the root causes of this light scattering through tool redesign and process manipulation. If successful, our window prototypes are expected to significantly improve energy loss through window surfaces, at a similar or better price per window unit than what is currently commercially available.