Once again evolution has come up with an ingenious design, this time a multilayered protective material with a range of potential applications. The material was discovered in the shell of a deep-sea snail, Crysomallon squamiferum, which is able to withstand powerful crab attacks. Here is the summary of the new findings:
Biological exoskeletons, in particular those with unusually robust and multifunctional properties, hold enormous potential for the development of improved load-bearing and protective engineering materials. Here, we report new materials and mechanical design principles of the iron-plated multilayered structure of the natural armor of Crysomallon squamiferum, a recently discovered gastropod mollusc from the Kairei Indian hydrothermal vent field, which is unlike any other known natural or synthetic engineered armor. We have determined through nanoscale experiments and computational simulations of a predatory attack that the specific combination of different materials, microstructures, interfacial geometries, gradation, and layering are advantageous for penetration resistance, energy dissipation, mitigation of fracture and crack arrest, reduction of back deflections, and resistance to bending and tensile loads. The structure-property-performance relationships described are expected to be of technological interest for a variety of civilian and defense applications.
C. squamiferum’s shell is truly an evolutionary breakthrough providing material science with several new concepts for protective armoring. As one report explains:
the snail employs some unique tricks to protect itself. For example, the shell's outermost layer consists of strong particles of iron sulphide created in the hydrothermal vents, each around 20 nanometres across, embedded in a soft organic matrix secreted by the snail. This structure is designed to crack when hit, but in a way that absorbs energy.
Cracks spread only by fanning out around the iron sulphide particles. This "microcracking" not only absorbs energy, it also ensures that larger cracks do not form. What's more, the particles of iron sulphide may blunt and deform intruding claws …
A thick, spongy middle layer acts as padding to dissipate further the energy of the blow. This makes it less likely that the mollusc's brittle inner shell, which is made of calcium carbonate, will crack. …
Helmets, motorbikes and Arctic pipelines that collide with icebergs, leading to costly oil spills, could also benefit ...
C. squamiferum’s revolutionary shell design is yet another reason why evolution is so important to science as a whole.
