US scientists have demonstrated a new coating, derived from the ‘teeth’ that ring the suckers found on squid tentacles, which allows rips in cotton, linen and wool to ‘heal’ themselves.
Creating surfaces that can repair themselves, whether for clothing or more crucial applications like biomedical implants, has been the subject of a great deal of research in the field of materials science.
One approach is to use multiple layers of polyelectrolytes of opposite charges which when scratched diffuse through the film and repair the damage. Now scientists have demonstrated an innovative coating, shown in action below, which incorporates proteins from the unexpected source of the razor-sharp ‘teeth’ that encircle the suckers on some squid tentacles.
These structures owe their strength and stretchiness to suckerin proteins that are similar to the ones found in silks but potentially easier to manufacture in a lab. Composed of what are known as ‘beta-sheet’ polymer networks, their semicrystalline structure makes them thermoplastic, melting when heated and hardening again when cooled, and gives them a high elastic modulus in both wet and dry conditions.
By adding suckerin protein to a layered polyelectrolyte film, the team of researchers from Pennsylvania State University, Drexel University and the US Naval Research Laboratory created a coating that can be applied to fabrics. As shown in the video below, when pressed together in water, cut pieces of cloth that had been dipped in the coating reattached.
As well as applications for everyday self-healing clothing, the researchers say the substance could be used as a “second skin” barrier that would protect wearers from chemical and biological warfare agents.
The work, which has received funding from US Army and Navy, is reported in the American Chemical Society journal ACS Applied Materials & Interfaces.