Fingers emerged from sticky tape to form claws in a research project conducted at Purdue University (Indiana, US), which will be presented at a meeting of the Materials Research Society (MRS) in Boston from Sunday (Nov. 25) to Nov. 30, 2012. The Nov. 20, 2012 news release on EurekAlert describes the new ‘smart’ material,
Researchers used a laser to form slender half-centimeter-long fingers out of the tape. When exposed to water, the four wispy fingers morph into a tiny robotic claw that captures water droplets.
The innovation could be used to collect water samples for environmental testing, said Babak Ziaie, a Purdue University professor of electrical and computer engineering and biomedical engineering.
“It [the tape] can be micromachined into different shapes and works as an inexpensive smart material that interacts with its environment to perform specific functions,” he said.
Doctoral student Manuel Ochoa came up with the idea. While using tape to collect pollen, he noticed that it curled when exposed to humidity. The cellulose-acetate absorbs water, but the adhesive film repels water.
“So, when one side absorbs water it expands, the other side stays the same, causing it to curl,” Ziaie said.
A laser was used to machine the tape to a tenth of its original thickness, enhancing this curling action. The researchers coated the graspers with magnetic nanoparticles so that they could be collected with a magnet.
“Say you were sampling for certain bacteria in water,” Ziaie said. “You could drop a bunch of these and then come the next day and collect them.”
Sticky tape is one of my favourite pieces of science equipment along with inkjet printers and ‘Shrinky Dinks’ as I noted in my Nov. 16, 2012 posting about bio-ink. The Nov. 20, 2012 news release by Emil Venere can also be found on the Purdue University website along with photos and other materials such as this animated GIF of the gripper closing available at https://engineering.purdue.edu/ZBML/img/research/plain-gripper-closing.gif.