Photo Credit: Nat. Commun.
Oil and water usually don’t mix, but when the two end up together, say in an oil spill or in an emulsion, they can be nearly impossible to completely separate. But by combining a water-loving polymer with an oil-repelling silicon-based material, researchers have created a new breed of membrane that can separate bulk amounts of any type of oil-water mixture by simple gravity filtration.
The scientific team that created the hygro-responsive membrane, as it is called, believes it will become an energy-efficient, cost-effective means of cleaning up oil spills.
When an oil-water mixture or emulsion is poured onto one of the membranes, nothing appears to happen at first, Kota explains. After a few moments, rough microcrystalline silsesquioxane regions on the membrane surface reconfigure to form a smooth, noncrystalline surface that allows the polymer to hydrogen bond with water. This reversible change in surface morphology allows water to completely wet the surface and permeate the membrane, which holds back the oil.