Fog problems
There has never been a good solution for clearing fogged-up windshields of vehicles. Car windows, eyeglasses, camera lenses, a windscreen or a pair of glasses even bathroom mirrors keep fogging up. More than just a nuisance, fogging can pose a driving hazard. Glass fogs up when warm, moist air comes into contact with glass and cools so that thousands of tiny water droplets form on the glass. The droplets scatter light, making oncoming traffic hard to see. Most current solutions don't work: anti-fogging sprays are short-lived; and windshields coated with titanium dioxide require exposure at least every few hours to ultraviolet light to work.
Eliminating fog
The existing technologies for example put different types of materials onto that lens that promote this spreading of water using materials that really like water, in fact in some cases the very same materials that are used in diapers are used on the surfaces of lenses, for example, because they love to draw water and spread it out across the surface.
To address this problem researchers at MIT have come up with a coating that could prevent fog made of just tiny water droplets that scatter light from forming in the first place using a coating.
Coating composition
The superhydrophillic water loving coating is composed of nanoparticles made of silica, the same material that glass is made from, to create a coating with a rough surface, to keep moisture from blocking light although it looks smooth to the naked eye.
These very tiny particles of glass are assemble onto a surface using polymer chains. A polymer chain is a long chain-like molecule and in this case the developed the polymer chain has a positive charge, whereas the glass particles have a negative charge and positive to negative attractive force is used to build these layers up onto the surface. The net result is a very porous coating that has lots of holes in it.
The nanosilica particles form layers of tiny pores and the pores attract the tiny droplets of water that make up the foggy surface. Stacked ten to twenty layers thick, with air pockets in between, these pores create what's called a "wicking" effect, which forms the water droplets into a uniform sheet. When a droplet falls on that surface, the water is drawn into these pores instantaneously and wicked away into a uniform sheet. The net result is no water droplet is formed on the surface that can scatter light, but leaves a nice transparent lens in this case.
The researchers claim that this is a cheaply produced technology having added benefit of increasing the clarity of unfogged glass. It reduces the glare and allows more than 99 percent of light to pass through the glass, compared to untreated glass that scatters between four and eight percent of light. The coating also acts as an anti-reflection coating allowing more light to pass through.