Unmixing oil and water

A new filter that separates the two substances only using gravity could help clean oil spills

Oil and water’s disdain for each other is legendary, but once forced to comingle they’re nearly impossible to separate. Now scientists have developed a specialized filter that cleanly separates the two, allowing water to pass through and leaving oil behind.

A blend of compounds coating stainless steel mesh (top) or polyester fabric (bottom) allows water (blue) to wet the surface while oil (red) is repelled and beads up.