A team of University of Illinois engineers have developed a self-healing system restoring electrical conductivity to cracked circuits. The fix happens so quickly service disruptions don't occur. The team used their technique for self-healing polymer materials and adapted it for electrical conduction.
The research team used tiny microcapsules — 10 microns in diameter — on top of the gold lines that function as circuits. As a crack occurs, the capsules break open and release liquid metal contained inside; the metals fill the gap and the electrical flow continues.
The researchers demonstrated that 90 percent of their samples healed to 99 percent of original conductivity, even with a small amount of microcapsules.
This new self-healing system is also localized and autonomous. That means the microcapsules only affect and repair at the point of damage and do not involve the rest of the conductor. It also self diagnoses the problem - no need for human intervention.
This is a huge benefit with items such as batteries where you can't open them, or where finding the source of a failure is difficult, such as airplanes, spacecraft, medical equipment or the advancing field of robotics that use miles of conductive material and service interruptions are not an option.
Aerospace engineering professor Scott White and materials science and engineering professor Nancy Sottos were the principal authors of a paper outlining the process, recently published in the journal Advanced Materials.
"What's really cool about this paper is it's the first example of taking the microcapsule-based healing approach and applying it to a new function," White said. "Everything prior to this has been on structural repair. This is on conductivity restoration. It shows the concept translates to other things as well."
The implications are great. These days microchips are getting smaller but also as dense as possible to provide maximum output. The problem is these chips are sensitive; a failure could occur from constant variations in temperature cycling or just simple fatigue and overload.
When one area in a chip causes a shut down of a device or warrants the replacement of an entire chip (or product for that matter) it is both inefficient and wasteful. The self-healing technique could prolong the life of many of our electronics.
The Illinois research team has plans to refine their system and expand their research into using microcapsules to control conductivity and are particularly interested in applying the microcapsule-based self-healing system to batteries, making them safer and last longer.
Check out their video on how self-healing process works.