Nanomotors could help electronics fix themselves

Electronics such as solar panels and flexible gadgets may someday be able to heal their "wounds," thanks to tiny, self-propelled nanoparticles that detect and repair damage. Microscopic scratches in electrical circuits can interrupt the flow of electricity and seriously impact the performance of devices, but such scrapes are hard to detect and even harder to repair, researchers say.

Now, engineers from the University of California, San Diego (UCSD) and the University of Pittsburgh have designed so-called nanomotors that can autonomously detect and move toward these scratches before wedging themselves into the cracks.

Because the particles are made from gold and platinum, which conduct electricity, they bridge the gap — healing the wound — and complete the circuit again, according to the researchers. The nanomotors are applied in a liquid solution that also contains the hydrogen peroxide fuel that powers them.

Tiny particles found in the blood of mammals called platelets inspired the design of the system, said the scientists. “These platelets clump together at the site of a wound to form clots that stem bleeding and help the wound heal.”

To build the nanomotors, the researchers first created tiny gold spheres and coated one-half of each sphere with platinum, which acts as a catalyst to break down the fuel that propels them. Then, the gold hemispheres were specially modified to take advantage of the hydrophobic effect — the phenomenon that causes oil droplets to separate from water and merge together.

The cracks in electrical circuits are typically hydrophobic, so by making the particles hydrophobic too, the researchers were able to nudge the particles to naturally seek out scratches. The tiny particles are also drawn to other nanomotors, thus allowing them to form clusters that can bridge larger gaps in a circuit.
Scientists repaired a purposefully damaged electric circuit with nanomotors to demonstrate that the system could repair a deliberately damaged circuit consisting of a gold electrode, a direct power source and a red LED, within 30 minutes.

Scientists say that electronics' ability to self-heal could be particularly useful for solar panels, which are often placed in remote and hostile environments, as well as for future flexible electronics integrated into things like clothes that will experience a lot of mechanical stress.