|Shark's skin gives them protection from harm. / Photo by: Brian Gratwicke via Wikimedia Commons|
The skin of sharks is a wonder of nature that not only provides the animal with ample protection but also excellent water penetration and silent movement. Fascinated by it, a team of researchers successfully developed a near-perfect design on metal surfaces that mimicked the features of shark skin.
The tooth-like structure of shark skin has been honed by nature for 450 million years, and to replicate that, the researchers used short-burst laser pulses that only last for tiny fractions of a second. They applied the laser pulses on a metal surface and initial exposure altered its structure.
To closely duplicate the shark skin structure on the metal surface, the team needed to alter the angle and other parameters of the lasers. The result is a metal surface that has a super-hydrophilic pattern that can reduce drag in the water. The technique may be applied to build submarines or other submersible vessels to allow them to travel farther distances underwater while using fewer amounts of power.
“Our structures are very important to the military, Boeing, and NASA,” said Dennis Alexander, lead author of the study conducted at the University of Nebraska. “We’re emphasizing these structures using these surfaces in harsh environments, but there isn’t any metal surface we can’t functionalize.”
Aside from metal surface, the researchers also used natural materials, such as rose petals to test their laser pulses on. The laser-exposed petals gained super-hydrophobic property that caused rainwater to slide off of them. The petals showed reduced drag in water as well.
Due to the hydrophobic quality that the technique imbued on the materials, the researchers considered its potential in medical supplies to repel liquids, such as bodily fluids and blood, as well as its application in industries that need to reclaim space usually occupied by water, such as reducing ice build-up on power lines.
The group noted that the technique also enhanced the heat transfer of the material, which can help several types of commercial and military systems.