Someday, chemically protective suits made of fabric coated in self-healing, thin films may prevent farmers from exposure to organophosphate pesticides, soldiers from chemical or biological attacks in the field and factory workers from accidental releases of toxic materials, according to a team of researchers.
“Fashion designers use natural fibers made of proteins like wool or silk that are expensive and they are not self-healing,” said Melik C. Demirel, professor of engineering science and mechanics. “We were looking for a way to make fabrics self-healing using conventional textiles. So we came up with this coating technology.”
The procedure is simple. The material to be coated is dipped in a series of liquids to create layers of material to form a self-healing, polyelectrolyte layer-by-layer coating.
This coating is deposited “under ambient conditions in safe solvents, such as water, at low cost using simple equipment amenable to scale-up,” the researchers report today (July 25) online in ACS Applied Materials & Interfaces.
Polyelectrolyte coatings are made up of positively and negatively charged polymers, in this case polymers like those in squid ring teeth proteins.
“We currently dip the whole garment to create the advanced material,” said Demirel, who is also a member of the Huck Institutes of the Life Sciences. “But we could do the threads first, before manufacturing if we wanted to.”
A drop of water self-heals a multiphase polymer derived from the genetic code of squid ring teeth, which may someday extend the life of medical implants, fiber-optic cables and other hard to repair in place objects, according to an international team of researchers.
“What’s unique about this plastic is the ability to stick itself back together with a drop of water,” said Melik Demirel, professor of engineering science and mechanics, Penn State. “There are other materials that are self healing, but not with water.”
Demirel and his team looked at the ring teeth of squid collected around the world — in the Mediterranean, Atlantic, near Hawaii, Argentina and the Sea of Japan — and found that proteins with self-healing properties are ubiquitous. However, as they note in a recent issue of Scientific Reports, “the yield of this proteinaceous material from natural sources is low (about 1 gram of squid ring teeth protein from 5 kilograms of squid) and the composition of native material varies between squid species.”
So as not to deplete squid populations, and to have a uniform material, the researchers used biotechnology to create the proteins in bacteria. The polymer can then either be molded using heat or cast by solvent evaporation.
Read more: Water heals a bioplastic