Self-healing gel breakthrough could lead to flexible electronics

An electrical repairing gel that doesn't need any human intervention to function could be used to help circuits become more robust in the future.

abstract traffic and circuitry background in red and green

The fact that circuits are not designed to flex hinders product design, causes maintenance issues in the field, and is slowing the move towards bendable, rollable gadgets.

However, some scientists think they've got a solution. Researchers in the Cockrell School of Engineering at The University of Texas at Austin say they've invented a healing gel that doesn't need an application of light or heat to fix a broken connection.

Until now, you'd need "external stimuli" to mend cracks or breaks in circuits, Guihua Yu, the UT Assistant Professor who developed the gel, said in an article at UT News.


Circuits and batteries aren't designed to bend. Even a plain piece of wire has tolerances that, if exceeded, can create stresses that eventually cause a failure; soldering, while usually a strong fused connection, can display brittleness in harsh use; and PCBs are fundamentally hard and flat.

These limitations mean that, despite advances in tech, such as rollable solar panels, there's a limit to their use.

Care in handling

Electronics require care in handling. Rolling a solar panel too tightly, for example, will cause the wires between sections to break.

Rugged-ization of electronics usually involves the expensive building of a strong chassis, or tougher cases.

The scientists at UT think there's an alternative to that methodology: Let the circuits break and then fix themselves.

A tale of two gels

The conductive gel that the scientists have invented is created by mixing two gels. A polymer hydrogel is the conductor, and a "self-assembling metal-ligand gel" is the healer.

Zinc atoms create a structural glue that self-assembles.

In other words, it doesn't need intervention. It automatically "heals after a break," the UT News article explains.


Cleverly, where Yu's invention comes into play is that it could be used as a soft-joint in a known trouble-spot to join parts of the circuit.

"The self-healing gel would not replace the typical metal conductors that transport electricity," the article says.

"This gel can be applied at the circuit's junction points because that's often where you see the breakage," Yu said.

Organic chips

Alternatives for bendable electronics include organic chips. Researchers have recently discovered a way to let electrons flow faster in organic semiconductors.

The University of Vermont scientists working on the project think it will ultimately let flexible electronics be made cheaply. I wrote about that discovery in "Organic chips will let you roll up your PC."

Known problem area

But what's interesting about the self-healing gel is that it's not revolutionary in the same way that organic semiconductors are.

In the case of the gel, you'd use existing circuits and batteries and conceivably just add the gel at the known problem area in the circuit.


If, say, a flexible solar panel becomes stressed through misuse in the field, it just fixes itself.

Applications could include those found in a military theatre; remote oil and gas work; ruggedized automobile design like those required in developing countries; and even leisure activities, like camping.

"Yu's team is also looking into other applications," UT News says. They include energy storage where the product might be used within batteries to hold an electrical charge.

But the simplicity of using it as a soft-joint is probably the most seductive.

"One day, you could glue or paste the gel to these junctions so that the circuits could be more robust and harder to break," Yu says.

Copyright © 2015 IDG Communications, Inc.

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