Mesh that captures oil but lets water through

Ever heard of a mesh that can separate oil from water? Here's one that can go a long way in future environmental cleanups.

The mesh, developed by a team led by an Indian American scientist at the Ohio State University, lets water pass through but not oil, thanks to a nearly invisible oil-repelling coating on its surface.

Potential applications of the technology range from cleaning oil spills to tracking oil deposits underground.

"If you scale this up, you could potentially catch an oil spill with a net," said Bharat Bhushan Ohio Eminent Scholar and Howard D. Winbigler Professor of mechanical engineering at Ohio State.

The work was partly inspired by lotus leaves, whose bumpy surfaces naturally repel water but not oil.

"We've studied so many natural surfaces, from leaves to butterfly wings and shark skin, to understand how nature solves certain problems," Bhushan said.

"Now we want to go beyond what nature does, in order to solve new problems," he added.

The researchers sprayed a fine dusting of silica nanoparticles onto the stainless steel mesh to create a randomly bumpy surface and layered the polymer and surfactant on top.

The silica, surfactant, polymer, and stainless steel are all non-toxic and relatively inexpensive. A larger mesh net could be created for less than a dollar per square foot, according to researchers' estimate.

"In all our coatings, different combinations of ingredients in the layers yield different properties. The trick is to select the right layers," Bhushan said.

He explained that certain combinations of layers yield nanoparticles that bind to oil instead of repelling it.

Such particles could be used to detect oil underground or aid removal in the case of oil spills.

This work began more than 10 years ago, when Bhushan began building and patenting nano-structured coatings that mimic the texture of the lotus leaf.

From there, he and his team have worked to amplify the effect and tailor it for different situations.

The findings are described in the journal Nature Scientific Reports.