Engineering On The Edge

Cybertech has pretty much remained relegated to the realm of science fiction. Doctors and researchers have managed to add a few parts to the body, but implanted electronics still mainly reside in the mind of William Gibson. Not only do implants risk rejection, but most electronics have the potential to cause injury because the materials they are constructed from are far more rigid than the fleshy human body.

Researchers at Northwestern University’s (NU) McCormick School of Engineering have been working on the problem and recently published a paper titled “Three-dimensional Nanonetworks for Giant Stretchability in Dielectrics and Conductors” in the journal Nature Communications.

Northwestern University's Stretching Electronics Material. Courtesy of Northwestern University.

You might be asking why anyone would want electronics implanted in their body. Doctors would love to be able to monitor people with life-threatening conditions (such as heart problems) without frequent trips to the hospital. Electronic monitoring devices that were flexible enough to be implanted could give doctors up-to-the-minute details about their patients, allowing for testing to be conducted pretty much nearly anywhere (assuming anywhere has Wi-Fi, is my guess).

The researchers at NU, working in collaboration with other scientists around the world, have designed electronics that are able to stretch to more than 200% of their original size. According to NU, that is four times greater elasticity than is currently available. The secret to the breakthrough is the result of combining a porous polymer and liquid metal.

“With current technology, electronics are able to stretch a small amount, but many potential applications require a device to stretch like a rubber band,” said Yonggang Huang, Joseph Cummings professor of Civil and Environmental Engineering and Mechanical Engineering. “With that level of stretchability we could see medical devices integrated into the human body.”

A serious issue with stretching most electronics is a loss of conductivity. Circuits built from solid metals lose nearly all conductively when stretched. NU’s research team believes the combination of a stretchy polymer (polydimethylsiloxane) and a conductive liquid metal (EGaIn) has beaten the problem.

“By combining a liquid metal in a porous polymer, we achieved 200% stretchability in a material that does not suffer from stretch,” Huang said. “Once you achieve that technology, any electronic can behave like a rubber band.”

Below you’ll find a short clip of the new material’s stretching power.

Source: Northwestern University