Nanotech

A tabby cat with his whiskers. / Photo by: Anna Yakimova via 123RF

 

Whiskers are among many physical traits that make cats, dogs, and other pets adorable. Whiskers are essential to these animals so that they can receive vital information from their surroundings, and a team of researchers decided to develop an artificial version to mimic the whiskers' functions.

The artificial variant is called e-whiskers which are made of polymers. They cut outlines from a flat sheet of shape-memory polymers, materials that are rigid in room temperature but which become flexible when exposed to a certain amount of heat. Next, they patterned a flexible strain sensor on top of each outline that has a diameter of a human hair. Then, they exposed the bottom part of the cutouts to hot air to make them bendable and soft. The exposure to heat also makes the e-whiskers rise and convert them into three-dimensional structures. After assembling the whiskers, any changes in the resistance of the sensors allow correct tracking of every position of the said technology.

“We’ve created some of the highest density of e-whiskers to date… 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,” explained Dr. Walter Voit, an author of the study and an associate professor of materials science and engineering, and mechanical engineering at the University of Texas at Dallas.

The research team mentioned that prosthetics and robotics are the two big applications of e-whiskers. In prosthetic devices, tactile feedback is used to interpret sensory information from its surroundings and the artificial whiskers can support that need. Robotic units can also replicate the capabilities of the human skin to know textures of materials upon contact, which may help robots to become more human-friendly.

“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 Jonathan Reeder, the lead author of the study and a postdoctoral researcher at Northwestern University.