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This article is from
Creation 42(4):55, October 2020

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Spiders and ants inspire an unsinkable metal structure

Sneak peek of a powerful article from the latest Creation magazine

by Philip Robinson

Can you imagine being able to create “an unsinkable ship? A wearable flotation device that will still float after being punctured? Electronic monitoring devices that can survive in [the] long term in the ocean?”1

These are the ultimate aims of a research team from the University of Rochester who have created a new superhydrophobic (water-repellent) metallic structure.2

Hakan Soderholm / Alamy Stock PhotoDiving-bell-spider
Diving bell spider with air bubble under water
J. Adam Fensterfire-ants
A raft of fire ants resists being submerged by a twig because air is trapped between their hydrophobic (water-repelling) body surfaces.

Their design was inspired by two small creatures. One was diving bell spiders (Argyroneta aquatic) that bring air bubbles to a specially constructed underwater web. The second was fire ants (Solenopsis invicta) which in their rafting assemblies link their bodies together creating a waterproof fabric to stay afloat.3 Both creatures trap air in an enclosed area with their superhydrophobic bodies, so that even if submerged, the air cannot escape. The new metallic structure in effect does the same thing, retaining air even if submerged, which is the key to its success.

Lasers were used to etch the surface of two small metal aluminium plates with intricate micro- and nanoscale patterns that trap air. The two plates were then placed facing inwards so the etching was not exposed to external wear. They were also at just the right distance from each other to trap and hold air between them. “The superhydrophobic surfaces will keep water from entering the compartment even when the structure is forced to submerge in water.” Even after being weighted down for two months, when the weight was removed it immediately floated to the surface. The team also punctured the structure a number of times, but due to the etched superhydrophobic surfaces it still trapped air and kept the structure afloat.

The new structure would appear to have endless applications, many of which might improve safety in the boating industry. Of course the inspiration for such a structure came from what has already been designed and created. This speaks volumes about their divine maker!

David L. Husuperhydrophobic-treated-discs
Two superhydrophobic treated discs, joined by a plastic post at the correct distance to trap air, floating on water.
David L. Huhydrophobic-metal-water-discs
The discs on the left are untreated and unable to float. The discs on the right have been treated with the etching patterns to trap air. Despite being deliberately weighed down, once the weight is removed it immediately floats to the surface.

References and notes

  1. . Marcotte, B., Spiders and ants inspire metal that won’t sink, rochester.edu, 6 Nov 2019. Return to text.
  2. Zhan, Z. and five others, Highly floatable superhydrophobic metallic assembly for aquatic applications, ACS Appl. Mater. Interfaces 11(51):48512–48517, 6 Nov 2019. Return to text.
  3. . Mlot, N.J. and two others, Fire ants self-assemble into waterproof rafts to survive floods, PNAS 108(19):7669–7673, 10 May 2011. Return to text.

Helpful Resources

Inspiration from Creation
by Professor Stuart Burgess & Dominic Statham
US $14.00
Soft Cover