A project at North Carolina State University has produced wires that can be cut with a knife or scissors and be reconnected by hand at room temperature. This project is a continuation of one that produced wires made out of a gallium indium alloy that could stretch to 8 times the size of the original wire while remaining conductive. This gallium indium alloy is actually a liquid metal that is very conductive and only solidifies when exposed to oxygen while the unexposed core remains fluid. This liquid metal wire was put inside a casing of a commercially available self-healing polymer that can re-establish molecular bonds when pressed together. Although this polymer casing is not nearly as flexible, the casing allows the composite cable to be cut and easily mended by hand.
To make one of these cables, the NC State team used solid wire to carve a microchannel out of a 5mm in diameter cylinder of the self-healing polymer. Then, this channel, measuring about 1 mm is filled with the liquid metal gallium indium alloy completing the wire. When the cable is cut, the exposed liquid metal alloy oxidizes preventing leaking. When mending the cable, the alloy conducts immediately when both ends are touched and it takes 10 minutes for the polymer to re-establish its molecular bonds, at which point, the cables cannot be pulled apart by hand.
This type of cable could be used in environments that are high-stress dangerous or difficult to work in to facilitate repairs. They could be used to make complex, rearrangeable and conductive 3D structures or microfluidic circuits/networks. They could also be used for educational purposes in schools because of how easy they are to cut and rearrange at room temperature. There is no discussion yet as to the price of this wire.
A paper titled “Self-Healing Stretchable Wires for Reconfigurable Circuit Wiring and 3D Microfluidics” was published in Advanced Materials and authored by Etienne Palleau, Stephen Reece, Sharvil C. Desai, Michael E. Smith, and Michael D. Dickey. Research was supported by the NSF.