If you've ever bent a piece of wire or plastic back and forth until it broke, you understand one of the problems inherent in flexible electronics. The more circuits and connectors flex, the higher the likelihood they'll break, which can be a big problem for wearable electronics. While we've seen self-healing chips, gels and microcapsules before, a new material out of Pennsylvania State University (Penn State) brings auto-repair to dielectrics – the materials that insulate electric currents.
The material consists of plastic sheeting covered in boron nitride nanosheets. Boron nitride is a super-hard substance that's carbon-like in its structure. The sheets themselves are like graphene, but unlike that material, they resist – rather than conduct – electricity.
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To get the nanosheet-covered plastic to have self-healing properties, scientists added hydrogen bonding groups to the surface of the nanosheets. They then demonstrated that they could go so far as to cut the material in half and still have it repair itself. That's because when the two halves of the severed material were brought close to each other, an electrostatic charge pulled them together, restoring the hydrogen bonds and "healing" the material.
Not only was the healed material then able to demonstrate its restored strength by supporting a 200 g weight (about 7 oz) just 30 minutes later, it was also able to show that all of its functionality had been healed including its electrical resistance, thermal conductivity and insulating properties. What's more, the material was able to restore its properties after multiple breaks.
According to a Penn State report about the research, some forms of the material required heat or pressure to heal but others were able to fully restore themselves at room temperature. What's more, the boron nitride nanosheets are waterproof, so they could be used in wet environments (self-healing beach ball anyone?)
The team's research was published last month in the journal Advanced Functional Materials.
The entire process is available to watch in the video from Penn State below, and it winds up looking like a pretty amazing magic trick or some fancy camera work. But the only special effects here are those created by molecules.
Source: Penn State
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