Scotch tape, a versatile household staple and a mainstay of holiday gift-wrapping, may have a new scientific application as a shape-changing "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 Scotch tape - made from a cellulose-acetate sheet and an adhesive - is uniquely suited for the purpose. 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.
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.
The grippers close underwater within minutes and can sample one-tenth of a milliliter of liquid.
"Although brittle when dry, the material becomes flexible when immersed in water and is restored to its original shape upon drying, a crucial requirement for an actuator material because you can use it over and over," the researcher said. "Various microstructures can be carved out of the tape by using laser machining. This fabrication method offers the capabilities of rapid prototyping and batch processing without the need for complex clean-room processes."
The materials might be "functionalized" so that they attract specific biochemicals or bacteria in water.
This story is reprinted from material from Purdue University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.