Polytetrafluoroethylene was such a great invention because nothing sticks to it. Otherwise known as Teflon, this material owes its usefulness to the property of being hydrophobic (in other words, water—or anything dissolved in water—is repelled by it). Hence non-stick cookware.
A similar coating possessing the opposite property could also be imagined. Technically, this would be oleophobic, i.e., repelling oily substances. Even more useful would be something amphiphobic—a material rejecting both water and oil. This would be the holy grail of coatings, because of its potential to produce self cleaning surfaces, unsullied by any foreign intrusion.
A new publication brings this particular fantasy a bit closer to reality. Deng et al. managed to produce a “superamphiphobic” coating on a glass substrate that is both strong and transparent. Most impressive of all, it doesn’t take a research lab filled with expensive instruments and exotic reagents. All that is needed is to coat a simple glass slide with the soot from an ordinary paraffin candle followed by infusion with a fluorinated silane. Voila! The result is a fractal-like assembly of nanospheres that fends off water and oil, and even retains its favorable properties when damaged by sand blasting.
Reducing this laboratory finding to practical application will take additional ingenuity. However, as is often the case, Shakespeare foreshadowed the discovery:
“How far that little candle throws its beams! So shines a good deed in a naughty world.“
Tom Tritton is President and CEO of CHF.
CHF's Bob Kenworthy Explains Teflon on WNYC [CHF News]
Roy J. Plunkett [CHF Collections]