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Whiskers may seem like a cute addition to a pet, but they actually have a very important job of helping animals make sense of their surroundings. Now, researchers at the University of Texas at Dallas are exploring these little hairs. They have created electronic e-whiskers using shape-memory polymers, according to the University of Texas.

The hair-like electronics could help engineer electronic human skin, according to the researchers.

Their inspiration came from seal whiskers. Jonathan Reeder, lead author of the study who conducted the research in the Erik Jonsson School of Engineering and Computer Science, said seals use their whiskers for complex sensing.

“When they swim in the water, their whiskers actually feel the flow of water as they’re going,” said Reeder. “Tests have been conducted in which a blindfolded seal will find a fish swimming in the pool and can actually track the fish based on turbulence. The fish disturbs the water, the water disturbs the whiskers of the seal, and that gives it information about where the fish is. It’s the 3D structure of the whiskers that enables these advanced functionalities.”

Reeder joined forces with Dr. Walter Voit, associate professor of materials science and engineering and mechanical engineering, and the two started creating the electronic hairs.

The e-whiskers were cut out from a sheet of shape-memory polymer, which changes flexibility when the temperature changes. When heated it becomes flexible, but at room temperature it remains rigid. A flexible strain sensor was then patterned on each of the whiskers.

If the researchers blew hot air at the bottom of the cut outs, the material became malleable and soft. This caused the e-whiskers to come ‘alive’ and become 3D. When the whiskers were assembled, the researchers tracked each e-whisker position from induced changes in the resistance of the strain sensor.

“We’ve created some of the highest density of e-whiskers to date,” said Voit. “When you have a lot of sensors like this that can be dragged over a surface, you can then use them to measure many interesting properties. Our e-whiskers were able to detect force, pressure, proximity, temperature, stiffness and topography. As they brush up against — or whisk across — various materials, they mimic the sensing capabilities of human skin.”

Researchers said the two biggest applications for e-whiskers will be robotics and prosthetics.

“With e-whiskers, we can increase the types of information that can be obtained when grazing a sensor across a surface,” said Reeder. “In robotics, e-whiskers could replicate the functionalities of human skin by determining what’s hard and soft, hot and cold, smooth and rough. They could allow the robot to identify objects and interact with them safely, making the robots more ‘human friendly.’”

E-whiskers may not be as easy to integrate into prosthetics, though. Translating electronic signals into the ‘language’ of the nervous system is hard to achieve, Reeder said. Eventually, they hope they can both replicate and improve upon human function in prosthetics.

“The sensitivity of the e-whiskers to changes in surface topology and temperature, as well as the sensors’ response time, all exceed the capabilities of human skin by at least an order of magnitude,” said Reeder. “It’s not impossible for a person with a prosthetic to actually have better sensitivity than with the human hand.”

From left: Jonathan Reeder BS’12, PhD’16 and Dr. Walter Voit BS’05, MS’06. Credit UTDallas
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