Effects of surface nanostructures on self-cleaning and anti-fogging characteristics of transparent glass

Nanostructured transparent glass surfaces with self-cleaning and anti-fogging properties were fabricated using a non-lithographic, anisotropic etching technique. The superhydrophilic glass surface was achieved by nanostructuring pre-deposited SiO2 film in a glow discharge chamber. For superhydrophobicity, the surface energy of the nanostructured glass was lowered by treatment with 1H,1H,2H,2H-perfluorooctyl trichlorosilane. The self-cleaning and anti-fogging behavior was compared for glasses with different wettabilities by measuring the optical transmittance as well as the surface morphology and contact angles. In measuring the anti-fogging behavior, we included the effects of air flow impinging on the glass surface to emulate many practical situations. The superhydrophobic glass was superior to the superhydrophilic glass when considering both the self-cleaning and anti-fogging behavior with durability, particularly under air flow. The work can be used to fabricate transparent glass products for which minimizing surface contamination is crucial, e.g., eyeglasses, solar cells, and optical instruments.