In the first of these scanning electron microscope images, you see an arroyo-like crack running from top to bottom in one of Bielawski’s materials. The physical gap disrupts electrical conductivity from one side to the other because it is difficult for electrons to hop across.
Heating the material causes the material to convert to a liquid state which enables it to begin to flow into the crack.
When the crack is completely filled with material, electrical conductivity is restored.
Chemistry professor Chris Bielawski considers himself an “applications oriented” scientist.
The ultimate application driving his research, right now, is the creation of self-healing, electrically-conductive polymers.
“Basically, we envision wires,” he says, “that can sense when their structures have been comprised and can automatically repair themselves.”
Bielawski designed and developed such a material using a particular type of “N-heterocyclic carbene,” a molecule that, when synthesized with metallic salts, is both electrically conductive and structurally dynamic. At room temperature, the material is a solid that is capable of conducting electricity. However, if it becomes cracked or damaged, it can be conveniently converted into a liquid, which allows it to flow into neighboring cracks. At that point, the material can be reverted back to a solid, which effectively “heals” damaged areas.
Bielawski is two or three years away, he believes, from developing a prototype to the point where it’s ready to be handed over to industry for commercial development. That the basic process works, however, already represents a major advance in the field of self-healing electronics.
This article also appeared in the Spring 2008 issue of Focus magazine.
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