Durable ultra-hydrophobic glass coatings with optical quality

Recently, ultra-hydrophobic - thus highly contamination resistant self-cleaning surfaces have attracted much interest from both industry and fundamental research. However, the most serious drawback in the development of durable ultra-hydrophobic optical coatings is optical scattering due to the required surface roughness and second, the degradation of surface chemistry under environmental conditions. To overcome the issues of the current technology, a low-scatter ultra-hydrophobic coatings of optical quality that exhibits a continuous replenishment mechanism of the surface chemistry in order to allow extremely long lifetimes was developed. The nano-structured surface is covered with a thin hydrophobic agent, which is supplied by a diffusion mechanism from an underlying replenishment layer to provide the ultra-hydrophobic surface property. A method for the simulation of both wetting and light interaction was developed. This technique significantly speeds up the selection of coating materials and appropriate deposition conditions. Thus, it is possible to combine both optical quality and ultra-hydrophobicity. At the current stage of development, the ultra-hydrophobic surfaces begin to draw interest for both glass coatings in architectural and automotive applications, e.g., automotive rear view mirrors.