Squid and Secret Messages

Squid and Secret Messages


Jellyfish and squid create secret messages

This week, scientists are looking to the sea and its citizens again for a new human tech innovation.
We recently investigated the new invention of self-repairing fabric, which uses a polymer derived from squid sucker teeth to “heal” torn fabric without sewing. Now, a team out of the University of Connecticut has turned to squid and jellyfish skin for inspiration, developing a material that could obscure secret messages — and self-destruct after reading!
The researchers used man-made materials to mimic what happens when squid and jellyfish do to their skin to scare predators: Jellyfish wrinkle their skin to become opaque; and squid contract the muscles around their chromatophores (that is, the pigment sacs in the skin), revealing colours that may shock their predators into losing their appetite.
“Skin was replicated by placing a thin film of polyvinyl alcohol on a rubbery base of polydimethylsiloxane (PDMS). If it was wrinkled, for example, it would be opaque. When it was flattened out or if moisture was added, it would become transparent and expose a message.

Researchers added that the degree of crosslinking between polymer chains in the film could indicate whether the wrinkling was reversible. When there’s little or no crosslinking, it can only be smoothed out once, which can ‘self-destruct’ a message after reading.”
There could be other, non-spycraft-related applications for this innovation: if the crosslinking is to such a degree that the wrinkles can never be unwrinkled, a small patch of the material inside, say, a cellphone, could act as a “tell” to a vendor that a customer dropped the phone into a puddle — thus voiding the warranty.
It’s the result of our unfortunate bias as land animals that we have only begun to understand the wonderful functions of the humble squid, so I’m looking forward to “collaborations” between our species to come. I only hope we can offer something — being a human seems much less impressive now…!