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Self-healing, conductive synthetic skin

Stanford University fabric scientists have devised the starting time synthetic, plastic pare that is conductive, sensitive to touch on, and capable of repeatedly self-healing at room temperature. The most firsthand applications are in the realm of smart, self-healing prosthetic limbs that are covered in this synthetic skin — only in the long term, the plastic might be used to make self-healing electronic devices, or you lot might even elect to replace your fingertips (or other slice of peel) with the synthetic, bionic equivalent.

There are two important innovations hither: a synthetic material that tin repeatedly cocky-heal, and the fact that it's electrically conductive — meaning it can discover changes in pressure and temperature (i.e. it's sensitive, like existent skin). We'll tackle the self-healing bit beginning.

A diagram of the self-healing, conductive plastic -- polymer threads, with nickel particlesThe Stanford team, led by Zhenan Bao, started with plastic polymer that's held together with hydrogen bonds. In the world of chemistry, hydrogen bonds are special because they're much weaker than covalent or ionic bonds, and readily pause and reform. Water is probably the best case of hydrogen bonding: You can hands split a droplet of water in two, and yet they readily join back together (self-heal). In short, the plastic that Stanford created can be cut in half — and and then, when the segments are placed next to each other, they join dorsum together within 30 minutes at room temperature.

To make the plastic conductive, the squad simply mixed in some microparticles of nickel. The nickle particles bond with the polymer and permit electricity to catamenia across the pare, effectively jumping between the nickle particles similar stepping stones. The nickle also increases the mechanical strength of the synthetic skin. Curiously, the team tried using carbon nanotubes instead of nickel, but they did not play well with the polymer and thus didn't increase electrical conductivity.

The terminate result is an electrically conductive, self-healing constructed skin. In testing, the researchers cut the skin in half with a scalpel, then pushed it dorsum together. Within a few seconds, the skin had regained 75% of its mechanical forcefulness and conductivity — within 30 minutes, the pare was fully restored. As far as its electrical properties go, the pare is adequately conductive, and its electrical resistance changes depending on pressure and tension. For example, if y'all had a prosthetic hand covered in this skin, it would theoretically be possible to catechumen an incoming handshake into electrical signals that are then wired into your nervous system.

The tensile strength of the self-healing, conductive synthetic skinBeyond prosthetics, this polymer could also be used to coat wires — and if they break, the polymer would cocky-heal and restore conductivity. This could be a useful fallback in electrical/computer systems that cannot fail, or in sprawling systems with very hard-to-attain wiring. (See: Liquid metal capsules used to make self-healing electronics.)

The squad is at present working on a stretchy and transparent version of the cocky-healing plastic, which would increase its potential uses dramatically. Before nosotros know information technology, your smartphone or tablet might have a self-healing touchscreen brandish.

Research paper: doi:x.1038/nnano.2012.192 – "An electrically and mechanically self-healing composite with pressure level- and flexion-sensitive properties for electronic skin applications"