Defeating oil stains with water

18:13 August 19, 2009 PDT

To create easy-to-clean surfaces, scientists have developed coatings for use on an array of materials, including fabrics, glass, concrete and windshields (Photo: Aldridged, Dreamstime.com)

Dishpan hands and poor visibility—two seemingly unrelated yet annoying by-products of some of life’s more mundane experiences—may soon become vague memories of an un-environmentally world, thanks to research in self-cleaning plastics.

While it’s true that water and oil don’t mix, water may soon be all a person needs to completely remove any trace of an oil spill - provided the surfaces are coated with newly designed polymer materials that would do away with harsh chemical detergents and solvents. And if you have ever been inconvenienced by fog on your bathroom window, car windshield, or eyeglasses, the same materials can be used as an anti-fog agent with similar eco-friendly benefits.

Research in self-cleaning plastics has led to the creation of a new development of ready-to-use, easy-to-apply polymers. A bottom layer of polyethylene glycol attracts water while a Teflon-like molecule forms the upper layer that creates an oil-resistant barrier. The polymer coating results in surfaces such as glass, plastic or concrete that upon cleaning, absorbs water instead of oil, leaving the surface stain-free.

According to Jeffrey Youngblood, Ph.D., a materials engineer from Purdue University, “a lot of people overlook the fact that pure water will generally not remove oil from a surface, but using this product transforms water into a super detergent.”

Not that “detergent” as we know it plays any part. Youngblood states that the polymers are “eco-friendly coatings—environmentally ‘green’…they eliminate the need for harsh detergents and solvents in settings ranging from home kitchens to industrial machine shops that must contend with heavy oils spills.” One only needs to consider the vast amount of phosphates in cleaning products that are subsequently introduced into waterways to understand the impact this research could have for both commercial and home use.

As for anti-fog capabilities, preliminary tests of the polymer coating on glass surfaces indicate a promising shelf life for this product with no decrease in performance.

Youngblood is currently investigating how metals and ceramics react when these polymers are applied to them, and predicts that these self-cleaning plastics will be made “commercially available within a few years."

The report was presented at the 238th National Meeting of the American Chemical Society (ACS).