Science

World's smallest micro-gripper is activated by light

World's smallest micro-gripper...
A color-enhanced scanning electron microscope image of the micro-gripper (bottom right), with the head of a Formica polyctena ant added for scale
A color-enhanced scanning electron microscope image of the micro-gripper (bottom right), with the head of a Formica polyctena ant added for scale
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A color-enhanced scanning electron microscope image of the micro-gripper (bottom right), with the head of a Formica polyctena ant added for scale
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A color-enhanced scanning electron microscope image of the micro-gripper (bottom right), with the head of a Formica polyctena ant added for scale

Some of the most useful tools are the ones that allow you to grab something. However, what if that "something" is very, very small? Well, that's where a new light-activated micro-gripper could come in – it's said to be the world's smallest.

The experimental device was developed via a collaboration between scientists at Poland's University of Warsaw and the Cracow-based AGH University of Science and Technology.

To build the tool, the researchers started with two optical fibers that were joined together to sit side-by-side, like the barrels of a double-barrelled shotgun. Each fiber had a diameter of 125 microns, which is approximately the width of a human hair. Additionally, they both had a liquid crystal elastomer (LCE) material deposited on their tips.

When ultraviolet light was subsequently run through the fibers from their non-LCE ends, it caused the elastomer to polymerize, permanently forming into two elongated cone-like structures.

Now, when visible green light is run through those same fibers, the LCE cones absorb its energy. This causes them to bend in toward one another, grasping whatever might be between them. They remain in this closed state as long as the green light is applied, but open up again once it's shut off.

"This is actually an advantage, as some other materials need two colours: one to close, the other to open," U Warsaw's Dr. Piotr Wasylczyk tells us. "We only have one and it works on-off."

The research is described in a paper that was recently published in the journal Advanced Materials.

Source: University of Warsaw Faculty of Physics

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