It may seem small and unassuming, but the stainless steel mesh created by engineers at Ohio State University could be used to combat large oil spills. The researchers say only water is able to pass through the mesh due to an oil-repelling coating that’s almost invisible to the naked eye.
The team took inspiration from the bumpy surfaces on lotus leaves, which are natural repellants of water; the goal was to develop a coating that repelled oil as opposed to water. To accomplish this, the engineers utilized a polymer featuring surfactant molecules (which are used in soap and detergent).
Silica nanoparticles
They then summoned silica nanoparticles to form a bumpy surface on the mesh, and placed the polymer and surfactant on top. The researchers say their oil-spill solution is inexpensive – its costs less than $1 per square foot – and non-toxic.
The coating measures a few hundred nanometers in thickness, making it practically undetectable. However, due to its 70 percent transparency rate, the mesh appears slightly less shiny.
The engineers decided to use silica in part because of its transparency rate. They say the coating could be integrated into car parts (such as mirrors), but that it could not be used for things like windows.
Transparency in the 90-percent range
"Our goal is to reach a transparency in the 90-percent range," said mechanical engineering professor Bharat Bhushan. "In all our coatings, different combinations of ingredients in the layers yield different properties. The trick is to select the right layers."
The shape of the nanostructures is also important, which is why the team is currently researching the effects of a nanotube-made structure. "There are natural defects in the structure of the nanotubes," said research assistant Dave Maharaj. "And under high loads, the defects cause the layers of the tubes to peel apart and create a slippery surface, which greatly reduces friction."
The team's work was recently published in the journal Nature Scientific Reports.
Source: Ohio State University