Washington, Nov 21 (IANS) Scientists have turned scotch tape, a versatile household staple and gift fastner, into a shape−shifting "smart material".
Purdue University researchers used a laser to form slender half−cm−long fingers out of the tape. 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, professor of electrical, computer and biomedical engineering at Purdue.
"When one side absorbs water, it expands. The other side stays the same, causing it to curl. If you were sampling for certain bacteria in water, you could drop a bunch of these and collect them the next day," said Ziaie.
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.
These findings will be presented at a meeting of the Materials Research Society in Boston from Sunday onwards.
The six−campus Purdue University is in West Lafayette, Indiana, US.