Purdue Scientists Develop 'Self-Cleaning' Coatings that Repel Oil

By GreenerDesign Staff

WASHINGTON, DC — Purdue scientists working with polymers say they've developed "eco-friendly coatings" that can be applied in industrial and household settings to create surfaces that resist oil and can be cleaned with plain water, reducing the need for heavy duty detergents or solvents.

Jeffrey Youngblood, an assistant professor of Materials Engineering at Purdue University, provided a media briefing on the project yesterday at the 238th National Meeting of the American Chemical Society in Washington, D.C.

The polymer coatings, which can be applied to surfaces including glass and concrete, are 20,000 times thinner than a human hair and have two key layers: A bottom layer of polyethylene glycol, which attracts water, and an upper layer of a Teflon-like molecule that repels oil.

So when oil, whether in a machine shop or a kitchen, comes in contact with a concrete floor or a countertop coated with the substance, the surface resists the oil while attracting the water, said Youngblood in his presentation, which was videotaped.

"Water will just completely remove the oil, you don't need any soap," he said. "You prevent soaps from getting into the environment."

The substance can also be used to prevent fogging either by coating a surface with it or adding it to a product.

A graduate student added the substance to a glass cleaner and sprayed it on half his bathroom mirror, then the researchers turned on the shower taps and left the room. When they returned about 20 minutes later, half the mirror was fogged over, the other half was clear, said Youngblood, who also applied an early version of the stuff to his dive mask.

"It worked better than the commercial defogger, but not as good as spit," he said, adding that the formula has improved since.

So far the team has used glass, metals, ceramics, aluminum and cement as substrates. Youngblood said the researchers are also interested in the substance's application with plastics, nylon, resins and wood. In addition, they're looking into use of the material and fabrics to make the textiles stain resistant.

Youngblood said the coatings may be commercially available in a few years.

The role of polymers in the cleaning process is also being developed by scientists in the United Kingdom.

Earlier this year at the international Clean Show 2009 in New Orleans, researchers from the University of Leeds, who formed a cleaning company startup called Xeros Ltd., and Cambridge Consultants rolled out a proof-of-concept washing machine that launders clothes with reusable nylon polymer beads and cuts water consumption by as much as 90 percent.

In the Xeros model, the nylon polymer beads are released into a load of wash that has been slightly dampened to create steam, which in turn activates polarizing properties in the polymer beads that then bind to -- or capture -- dirt and stains.

^{Image by Aldridged, Dreamstime.com, via the American Chemical Society}