Breakthrough in Self-Healing Electronics

Penn State researchers have developed a flexible electronic material that self-heals to restore many functions, even after multiple breaks. (Image courtesy of Qing Wang/Penn State.)

An international team of materials scientists and engineers has created a self-healing material that restores all electronic functions even after multiple breaks. This could greatly improve the longevity of wearable electronics. Even when cut completely in half, the material remains capable of complete repair without external influence.

Until now, restoring all electrical functions once a material is broken has not been possible. In order to create effective wearable electronics that are self-healing, the researchers incorporated a dielectric, or insulating factor, into the wearable electronics to preserve the material. After breaking, it is critical to maintain electrical resistivity and thermal conductivity to prevent electronics from overheating.

The researchers successfully created a material capable of restoring the following functions in electronics after a break:

Mechanical strength
Breakdown strength
Electrical resistivity
Thermal conductivity
Insulating properties

Impermeable Nanosheets

The insulating material of choice is a two-dimensional boron nitride nanosheet. The nanosheets are added to a plastic polymer base. By means of hydrogen bonding on the surface of these sheets, the naturally occurring electrostatic attraction draws the broken pieces closer together. When the hydrogen bond is restored, the material is healed. Factors affecting the healing capabilities are the amount of boron nitride nanosheets, heat and pressure.

Boron nitride nanosheet. (Image courtesy of Nanoscale.)

“Most research into self-healable electronic materials has focused on electrical conductivity, but dielectrics have been overlooked,” said Qing Wang, professor of material science and engineering at Penn State. “We need conducting elements in circuits, but we also need insulation and protection for microelectronics.”

Harder than other healable materials, the boron nitride nanosheets are also impermeable to moisture. Therefore, the dielectric material is more versatile than comparable materials, and the wearer will not have to worry about removing the device when exposed to different levels of humidity, or even submerging it in water.

“This is the first time that a self-healing material has been created that can restore multiple properties over multiple breaks, and we see this being useful across many applications,” said Wang.

The research findings are published in the journal Advanced Functional Materials.