Researchers have created an oil-repellent surface that becomes transparent in water, inspired by oil-repellent fish and a special flower that becomes transparent in contact with water.
By: Rinat Filosof-Barko
How do fish repel oil? By trapping water within their scales they create a self-cleaning, oil-repellent coating, a coating that drove part of the idea behind researcher Feng Chen and his team at Xi'an Jiaotong University.
Chen took the inspiration for the second part of the idea from the Diphylleia gravi flower, also known as the skeleton flower.
In the air its petals appear white, but as soon as they come in contact with water they become transparent, due to the change in the loose structure of the plant's leaf cells. On sunny days the ratio between the water and the water vapor in the petals causes a scattered reflection of the light and the petals appear white, while on rainy days water enters the petals, and the light passes through them easily, therefore they become transparent.
Using laserosec, a laser combined these two systems in a glass surface - it becomes transparent and repels oil when it is in water. Chen's student, Jiala Jung, emphasizes the value of "realizing the importance of a layer of trapped water between surfaces" and they hope to "apply this to an oil-repellent, transparent material for use in oil-resistant optical devices."
Researcher Liu from the University of Wisconsin, Madison, USA, is impressed by the method and the biomimetic inspiration, and regards it as a smart idea. "A transparent, oil-repellent surface provides researchers with more capabilities to design and invent optical devices for underwater use," he adds. And Du Deng, who specializes in innovative biomimetic materials at the Lawrence Berkeley National Laboratory, USA, says that the work is "an important step towards finding an easy and reliable way to make materials repellent to oil in an aquatic environment."
