The researchers, who noted that the cone-shaped spines of cactus can harvest water from the air and move it to their base due to surface tension and the shape of the spines, emulated that natural design function in a new development using artificial spines made from copper.
Although some advances have been made in oil clean-up technology, the tiny micron-sized droplets of oil remain difficult to remove, and this recent breakthrough could address that issue.
"Here we develop an oleophilic array of conical needle structures for the collection of micron-sized oil droplets, inspired by the collection of similar sized water droplets on conical cactus spines. Underwater, these structures mimic cacti and can capture micron-sized oil droplets and continuously transport them towards the base of the conical needles. Materials with this structure show obvious advantages in micron-sized oil collection with high continuity and high throughput." - Nature.com
The needles developed by the researchers are 5 millimeter long, made from copper and a silicone polymer, and are arranged in hexagonal arrays. The researchers report that these arrays can remove about 99% of oil mixed with water.