Next, the researchers plan to further refine their system and explore other possibilities for using microcapsules to control conductivity. They are particularly interested in applying the microcapsule based self-healing system to batteries, improving their safety and longevity.
Thermal and electronic conductivity
Most research into self-healable electronic materials has focused on electrical conductivity but dielectrics have been overlooked. There is need for conducting elements in circuits, but also for insulation and protection for microelectronics. Researchers have looked at developing a self-healing dielectric material. Dielectrics are just as important as conductors as these provide electronic insulation and packaging.
The material that a research team has created restores all properties needed for use as a dielectric in wearable electronics—mechanical strength, breakdown strength to protect against surges, electrical resistivity, thermal conductivity and dielectric, or insulating, properties.
Most self-healable materials are soft or gum-like, according to the team, but this material created is very tough in comparison. The team has added boron-nitride nanosheets to a base material of plastic polymer. Like graphene, boron-nitride nanosheets are two-dimensional, but instead of conducting electricity like graphene, these resist and insulate against it. The material can self-heal because boron-nitride nanosheets connect with hydrogen-bonding groups functionalised onto their surface.
When two pieces are placed in close proximity, electrostatic attraction naturally occurring between both bonding elements draws the two pieces close together. When the hydrogen bond is restored, the two pieces are healed. Depending on the percentage of boron-nitride nanosheets added to the polymer, self-healing may require additional heat or pressure. But some forms of the new material can self-heal at room temperature when placed next to each other. Unlike other healable materials that use hydrogen bonds, boron-nitride nanosheets are impermeable to moisture. This means that devices using this dielectric material can operate effectively within high humidity contexts such as in a shower or at a beach.
In the last 50 years, electronics has grown from vacuum tubes to discrete transistors to micro-chips with thousands of transistors together in an area the size of the head of a pin. The trend for ever smaller electronic devices continues even today. As electronic devices grow ever more intricate, so must the tools required to fix these!
Electronic circuits are very sophisticated these days, but a crack, even an extremely small one, can interrupt the flow of current and eventually lead to the failure of a device.
Traditional devices can be fixed with soldering, but repairing advanced electronic devices requires innovation. Replacing whole devices or even parts can be tricky or expensive, particularly if these are integrated in clothes or located in remote places. Creating devices that can fix themselves would be ideal.
Anticipating this challenge, scientists have turned to the body’s immune system for inspiration and are now building self-healing electronic materials that would restore all their functions after a material breaks. These self-healing electronic materials can seek out and repair faults in electronic systems.