Washington: Researchers have converted the humble scotch tape - a versatile household staple and an absolute necessity for gift-wrapping - into shape-changing smart material using nanotechnology.
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.
The Scotch tape - made from a cellulose-acetate sheet and an adhesive - is uniquely suited for the purpose.
"It 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."
The study will be presented during a meeting of the Materials Research Society in Boston.