A way to modify sticky tape inspired by kirigami, the Japanese art of paper cutting, could make it 60 times stronger, while remaining easy to peel off.
There are two main types of adhesives: strong ones that are hard to remove, such as duct tape, and those that can be easily peeled off, such as sticky notes. What is missing is an adhesive that combines the properties of the two – one that is robust but easily removed when needed, says Michael Bartlett at Virginia Tech.
Bartlett and his colleagues have come up with a solution based on kirigami. “Our inspiration was to use the geometry, or the cutting of the tape, to control its properties without having to redesign the chemistry,” he says.
To create the tape, the team laser-cut three sides of a rectangle in a repeated pattern in a strip of sticky tape, to create flaps (see photo). If you peel it off a surface so you encounter the uncut side of the rectangle first, it is easy to separate.
However, the team found that it was much harder to remove the tape if you peel in the opposite direction. Instead of one smooth motion, every time you encounter a cut in the tape you need to turn around and go back on yourself to separate it from the surface. This difficulty gives it its high strength: the researchers found that this simple modification could increase the adhesion of the tape by a factor of 60. “That means we can essentially take a piece of material like a Post-it note and make it as strong as duct tape,” says Bartlett.
The tape could be useful in situations where you need a high adhesion force in a specific direction, such as hanging a photo frame. What’s more, the team found that it can stick to a range of materials, including steel, glass, plastic and Teflon, and even works underwater.
In the future, Bartlett says that these modified tapes could be used in the manufacture of robots and electronics that may benefit from trouble-free disassembly.
“What is elegant about [this] work is the shockingly simple solution,” says Jamie Paik at the Swiss Federal Institute of Technology in Lausanne. “Unlike previous approaches, this method does not require any special combination of materials, manufacturing processes or moulds.”