Peeling stickers to pave way for stretchable electronics

June 16th, 2009 - 1:18 pm ICT by ANI  

Washington, June 16 (ANI): Focussing on stickers peeling from windows, scientists are hoping to develop a new way to precisely control the fabrication of stretchable electronics-electronic devices embedded into clothing, surgical gloves, electronic paper or other flexible materials.

Developing such stretchable electronics have proved difficult because the electrical wiring tends to be damaged as the material twists.

But a study, led by Massachusetts Institute of Technology (MIT) researchers, has offered a new approach to designing such circuits.

The researchers say that ultra-thin, flexible but strong materials-such as graphene-are ideal candidates for stretchable electronic applications.

Initially, they launched the project as an analysis of the wrinkling and delamination of stickers.

“It’s something that’s around you all the time - but if you look at it a different way you can see something new,” said Pedro Reis, applied math instructor at MIT and senior author of study.

Delamination commonly occurs due to different rates of heat-induced expansion between a thin film and the surface to which it is attached, and its common examples are the blisters formed in stickers attached to a window, when exposed to sunlight.

Besides, compression of the surface can also lead to delamination-as the surface is compressed, the film bends with it until it reaches a certain energy threshold, then pops away from the surface, forming small blisters.

The researchers performed well-controlled experiments to stretch and compress surfaces with thin films attached to them, and measured the dimensions of resulting blisters.

They found that blister size depends on the elasticity of the film and the substrate and the strength of adhesion between them.

With their model, they could predict the size of the blisters that would form under specific conditions.

The researchers also found that by intentionally creating delaminated surfaces, it was possible to design devices that would allow wires attached to a surface to move with the material without breaking.

And if the wires were already partially separated from the material, they would not break under stress from twisting and stretching of the substrate.

Using this approach, delamination could be precisely controlled by changing the strength of adhesion and the elastic properties of the film and wires.

“Delamination blisters have a characteristic size that they try to choose for themselves. We’ve characterized this size so that in principle it can be determined just from the parameters of a given system,” said a co-author of the study.

The study has been published in the online edition of the journal Proceedings of the National Academy of Sciences. (ANI)

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