Wednesday, December 26, 2007

Self-Cleaning Glass



This photo was a revelation - an answer to a problem constantly faced by car drivers during the monsoons. When you are driving through rain, wind-screen wipers and air circulation can deal with raindrops and fogging but what about the rear-view mirrors? How is it that this mirror looked like half of it was wiped clean?

Photocatalytic Technology has the answer. Half of the mirror is coated with compound that is abundant in nature - Titanium Oxide. For a long time now, TO has been used as a white pigment in paint, cosmetics and food additives,. Now people was warming up to its uses as a photofunctional material. Compounds that are perfectly functional and yet, do not harm the environment.

Useful properties & applications: -
  • When TO absorbs ultraviolet light, any organic dirt or grime on its surface is decomposed through a process called photo-induced decomposition. Perfect for coating glass windows in high-rise buildings.
  • TO surface has an affinity for water (photo-induced hydrophilic effect). Buildings coated with it decompose organic dirt under sunlight (UV light) and are easily washed away by rain.
  • On a TO surface, water spreads into a thin film and does not form droplets -- a very useful property when used on automobile glass and side-mirrors.
  • Combining TO with a safe anti-bacterial agent such as silver and copper makes a material with high anti-bacterial properties when it is irradiated with weak UV light from regular indoor lighting. Very useful in hospital emergency rooms and senior-citizens homes.
(Source: JJ Environment Report, Oct., 2007)

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