Clean up oil spills without using toxic chemical dispersants, in situ burning, or biological agents? Scientists at the University of Michigan believe they have a working solution that can do just that.

In a paper titled “Hygro-responsive membranes for effective oil-water separation” published in the August 28 issue of Nature Communications, researchers announced they have developed a smart filter with a shape-shifting surface that works to separate oil and water by harnessing the power of gravity. The filter they created repels oil but attracts water, which is the opposite of how most typical materials work.

“Our material operates in a counterintuitive way,” said Anish Tuteja, assistant professor of materials science and engineering at the university and corresponding author of the paper. “Water spreads on its surface, while the oil beads up. It’s hydrophilic, so it loves water, and oleophobic, so it hates oil.”

The coating they apply to the filter – which is made from standard stainless steel window screen and polyester fabric – is a new blend of a commercially available polymer and a novel nanoparticle developed by project collaborators at the Air Force Research Laboratory. The polymer bonds with the water molecules and the nanoparticle, which is very low in surface energy, does not get wet by the oil. Gravity and the capillary action phenomenon – which enables liquids to defy gravity in narrow enough spaces – does the rest, pulling just water through filter and leaving behind the oil. In lab tests the researchers found that they could separate the oil and the water with 99.9 percent efficiency.

“This is one of the cheapest and most energy-efficient ways to separate oil and water mixtures,” said Tuteja. “It has never been demonstrated before.”

In addition, they also found that the filter was effective even after detergents had already been added to the oil/water mix and that over the course of 100 hours of testing the filter never got clogged up. This is a major step-up from current filtration technology used to clean up oil spills.

The university is now seeking commercialization partners to bring the chemical and detergent-free oil filter to market. Kevin Costner, have you heard about this yet?

Check out video of the smart filter in action:


Image Credit: University of Michigan