I recently bought an iPhone 3GS and if you’re not familiar with it, it basically relies on the whole screen as an input device (typing, touching to select programs, dialing numbers). There are no buttons. This means that it’s easy to leave fingerprints on the touch-screen, especially if you’re fingers are greasy from sweat, etc… Despite this fact, I noticed that as I let the phone sit for a period of time, all of the finger prints/smudges disappeared or evaporated. I had a feeling there was some technology involved here, as it looked like a typical glass screen, but didn’t hold finger prints like one. Today I decided to learn how this is possible, and found that the iPhone screen is coated with a special oleophobic polymer, a plastic that human skin oil doesn’t adhere to very well.
The Applers were able to do this by bonding this oleophobic polymer to glass. The polymer is an organic (from organisms) compound, carbon-based. The glass is nominally inorganic, silicon-based… solid rock. The trick is getting the one to stick to the other. Although it is nominally proprietary, this is probably done with a third molecule that sticks to silicon on one side and to carbon-based polymers on the other side. Chemical engineers get it to stay stuck by inducing compounds to diffuse or “inter-penetrate” into the polymer. The intermediate chemical is a “silane,” a molecule that has silicon and alkanes (chains of carbon atoms).
Pretty neat huh? I can’t imagine how dirty and smudged the iPhone 3GS screen would be without this technology. I wonder if the new Droid phone (a new iPhone competitor) or any other touch screen phones have this same technology? If they don’t they’re at a serious disadvantage to the iPhone 3GS!