Human skin has unique properties that are difficult to replicate—it combines strength and flexibility, and has the ability to self-repair within 24 hours of injury. Artificially synthesized gels could only achieve one of these properties, but that was before the discovery by scientists at Aalto University in Finland and the University of Bayreuth in Germany.
Human skin has unique properties that are difficult to replicate—it combines strength and flexibility, and has the ability to self-repair within 24 hours of injury. Artificially synthesized gels could only achieve one of these properties, but that was before the discovery by scientists at Aalto University in Finland and the University of Bayreuth in Germany.
To achieve the properties of human skin in a solid hydrogel, the researchers used ultra-thin clay nanoplates. These sheets created a tightly woven network of polymers that strengthened the hydrogels and prevented them from being too soft. They also enhanced the gel's ability to self-heal, writes Interesting Engineering.
The scientists mixed the monomer powder with water containing the nanoplatelets. Then they placed the mixture under a UV lamp. The lamp's ultraviolet radiation causes the individual molecules to bond together, turning the whole thing into an elastic solid — a gel.
The innovation in question relies heavily on the subsequent interaction of polymers. “Entanglement means that thin polymer layers start to twist around each other, like tiny woolen threads, but in a random order,” adds Hang Zhang from Aalto University. “When the polymers are fully entangled, they are indistinguishable from each other. They are very dynamic and mobile at the molecular level, and when you cut them, they start to entangle again.”
The healing process is phenomenally fast. The hydrogel recovers 80-90% within the first four hours after cutting and is fully recovered after twenty-four hours. The hydrogel has about 10,000 layers of nanosheets in a one-millimeter-thick sample, allowing it to achieve stiffness similar to human skin while still allowing it to stretch.
This innovation opens a window to new possibilities in the field of wound healing, soft robotics, artificial skin, and more.
