Apples solution didnt rid the phone of fingerprints and smudges very effectively, but Apple has stuck with its oleophobic surfaces. New iPhones and iPads ship with oleophobic screens. And the company has certainly invested in research on oil-resistant screens: In February 2011, Apple filed a patent on a special process for applying an oleophobic polymer to the surface of a touchscreen.
Physical screen texturing
The most promising research in oleophobic surfaces involves the physical texturing of screen surfaces. Last December, Max Planck Institute researchers published a paper in the journal Science saying that regular sootthe carbon residue released from a burning candlecan create a rough, oil-resistant surface.
The researchers coated a slide with candle soot, then covered the layer of carbon residue with a layer of silica structures and baked the whole thing at 1112 degrees Fahrenheit, which made the layer of soot transparent.
During tests afterward, the researchers found that oil and dirt particles were repelled by the surface, that they bounced right off the surface of the slide, and did not break apart and scatter about.
Not only did the surface seem to work exceptionally well against fingerprinting, but it was a relatively cheap and simple solution. The only problem was that the surface wasnt very robust and stable and could easily be scratched off.
Hybrid approach holds most promise
The most promising attempts to create the transparent, oleophobic surfaces that touchscreen makers need use a hybrid approach. Simply using chemicals will not get it done; what is needed is a dramatic combination of chemical treatment and texturing, says Neelesh A. Patankar, professor of theoretical and applied mechanics at Northwestern University.
Patankar says (and others agree) that the research with the best chance of leading to a real nonsmudge touchscreen is a hybrid solution being developed by a pair of MIT researchers named Gareth McKinley and Bob Cohen.
The two began a project in the mid-2000s developing liquid-resistant surfaces for the Air Force, which wanted to make materials like O-rings resistant to liquids like jet fuel. Jet fuel, McKinely explains, is a liquid with low surface tension, which means, in very simple terms, that it forms droplets easily.
Liquids like fingerprint oil and sweat, as it happens, also have low surface tension, because theyre both full of bodily secretions like lipids and fatty acids, McKinley says. This is why they are so hard to remove, he says. They want to spread over everything.
The suggestion that McKinleys and Cohens surface treatment might repel finger oil and sweat caught the attention of the computer industry. After we released a couple of research papers in 2007 and 2008 describing our results, we immediately began getting calls from technology companies, McKinley explains. Some in the tech industry saw in the research a possible opportunity to make smudge-resistant touchscreens.
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