The main thing to note about self-cleaning windows is that they’re not, truth be told, “straightforward bits of glass.” They have a flimsy external covering of titanium dioxide, a white, fine titanium compound best known for giving that astonishing sparkle to paint, toothpaste, and a wide range of other splendid white things. Presently if titanium dioxide is, basically, the white in white paint, it may appear to be silly to sprinkle it all over a window—something we normally need to be transparent. In any case, the covering truly is ultra-ultra slight. We’re looking at putting a layer 10–25 nanometers profound on the glass that may be 4mm thick, which resembles sitting a dime over the Empire State Building! It diminishes the light going through the glass by close to around 5 percent.
The titanium dioxide covering cleans through a one-two punch, two-organize process: it’s photocatalytic (light-actuated) and hydrophilic (water-adoring)— however, we should not get hoodwinked by the language.