Rochester University researcher have drawn inspiration from diving bell spiders and fire ants to create a new type of metal with water repellent properties.
According to the scientists, the new metallic structure is so superhydrophobic that it refuses to sink, no matter how often it is forced into water or how much it is damaged or punctured.
The new metal could ultimately pave way for unsinkable ships, wearable anti-puncture flotation devices, and even ocean-based electric monitoring devices, contends Rochester professor Chunlei Guo.
The structure was made using a groundbreaking technique that utilizes femtosecond bursts of lasers to ‘etch’ the surfaces of metals with intricate micro- and nanoscale patterns.
It is these patterns that trap air and make the surfaces superhydrophobic, or water repellent.
Initially, the scientists observed that the metal began to lose its hydrophobic properties when immersed in water for long periods of time.
To counter this, they drew inspiration from spiders and fire ants that survive long periods under or on the surface of water by trapping air in an enclosed area.
For example, the Argyroneta aquatic spiders is known for creating an underwater diving bell-shaped web which they fill with air carried from the surface between their super-hydrophobic legs and abdomens.
Fire ants too form a raft by trapping air among their superhydrophobic bodies.
Guo’s lab created a structure in which the treated surfaces on two parallel aluminum plates face inward, not outward, so they are enclosed and free from external wear and abrasion.
The surfaces are separated by just the right distance to trap and hold enough air to keep the structure floating, making it more or less like a waterproof compartment.
Even after being forced to submerge for two months, the structures immediately bounced back to the surface after the load was released, notes Guo.
The structures also retained this ability even after being punctured multiple times, because air remains trapped in remaining parts of the compartment or adjoining structures.
Though the team used aluminum for this project, Guo contends that the etching process could be literally used on any metal, or other materials too.
Image and content: University of Rochester